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2006 Integrated Orchard Management Guide for Commercial Apples in the Southeast Alabama Cooperative Extension System Auburn University University of Arkansas Division of Agriculture Cooperative Extension Service University of Arkansas Clemson Cooperative Extension Service Clemson University University of Georgia Cooperative Extension Service University of Georgia North Carolina Cooperative Extension Service North Carolina State University University of Tennessee Agricultural Extension Service University of Tennessee Poison Control Centers and Emergency Facilities PESTICIDE POISONING – Symptoms of pesticide poisoning may include headache, blurred vision, weakness, nausea, cramps, diarrhea, and chest discomfort. If any of these symptoms occur during or after mixing or applying pesticides or if an unintended unprotected exposure such as a spill occurs, stop work at once and take appropriate action. If pesticide is spilled on the skin, immediately wash the area thoroughly with large amounts of soap and water. If pesticide is in the eye, flush the eye for 15 minutes in running water. If pesticide is inhaled, move to open, clean air. If pesticide is ingested, rinse out the mouth. Follow all label first aid directions. Give CPR if indicated. Get help. Contact your physician or poison control center (listed below or on WPS safety poster). Transport the victim to the closest medical care facility. Take the pesticide container or the label with you, or have others search for the label and get it to the facility. Most pesticide poisonings are due to overexposure to organophosphate and carbamate insecticides. Investigation indicates these are the result of misuse, disregard for safety precautions, and lack of proper hygiene during mixing and application. Ninety percent of occupational exposure is through the hands. Use neoprene or butyl rubber gloves. Rubber boots prevent acute exposure from spills and chronic exposure from accumulation of residues in materials of boots and shoes. STATE-DESIGNATED POISON CENTERS ALABAMA Regional Poison Control Center 800-292-6678 The Children’s Hospital of Alabama 205-933-4050 (business) 1600 7th Ave South Birmingham, AL 35233-1711 ARKANSAS Poison and Drug Information Center 800-482-8948 University of Arkansas for Medical Sciences 4301 West Markham-Slot 522 Little Rock, AR 72205 GEORGIA Georgia Regional Poison Control Center 800-282-5846 Grady Memorial Hospital 404-525-3323 (for the deaf) 80 Butler Street South East 404-616-9000 (business) Atlanta, GA 30335-3801 NORTH CAROLINA Carolinas Poison Center 800-848-6946 (in NC) Carolinas Medical Center 800-222-1222 (nationally) 1000 Blythe Blvd 704-355-4000 (business) Charlotte, NC 28232-2861 SOUTH CAROLINA Palmetto Regional Poison Control Center 800-922-1117 College of Pharmacy 803-777-1117 (local) University of South Carolina 803-777-7909 (business) Columbia, SC 29208 TENNESSEE Southern Poison Control Center 901-528-6048 848 Adams Ave. Memphis, TN 38103 2006 Integrated Orchard Management Guide for Commercial Apples in the Southeast Table of Contents Pest and Orchard Management Program . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Tree Row Volume: A Model for Determining Spray Volume . . . . . . . . . 27 IPM Practices for Selected Pests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Pesticide Resistance Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Effect of pH on Pesticide Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Orchard Floor Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Apple Pollination, Honey Bees, and Pesticides . . . . . . . . . . . . . . . . . . . . 38 Soil and Plant Analysis Guidelines for Southeastern Apple Production . 39 Fertility Management Recommendations for Apples . . . . . . . . . . . . . . . . 40 Relative Effectiveness of Fungicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Relative Effectiveness of Insecticides and Miticides . . . . . . . . . . . . . . . . 43 Toxicity of Pesticides to Beneficial Arthropods . . . . . . . . . . . . . . . . . . . . 45 Weed Response to Preemergence Herbicides . . . . . . . . . . . . . . . . . . . . . 46 Weed Response to Postemergence Herbicides . . . . . . . . . . . . . . . . . . . . . 47 Fungicides and Bactericides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Insecticides and Miticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Growth-Regulating Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Vertebrate Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Pesticide Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 EPA Registration Numbers of Various Materials . . . . . . . . . . . . . . . . . . . 75 Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of chemical products or services in this publication does not imply endorsement by the Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product before applying any chemical. For assistance, contact your local Extension Agent. Senior Editor: Jim Walgenbach, Extension Entomologist, NC State University Section Editors: Insect Management Jim Walgenbach Cultural/Growth Regulators Steve McArtney Disease Management Turner Sutton Vertebrate Management Dave Lockwood Weed Management Wayne Mitchem Contributors Alabama South Carolina John McVay Arlie Powell Ed Sikora Entomology Horticulture Plant Pathology Bob Bellinger Mike Hood Desmond Layne Guido Schnabel Safety Apiculture Horticulture Plant Pathology Arkansas Tennessee John Boyd Pat Fenn Donn Johnson Curt Rom Weed Science Plant Pathology Entomology Horticulture Steve Bost Edward Burgess Frank Hale Dave Lockwood John Skinner Plant Pathology Safety Entomology Horticulture Apiculture Georgia North Carolina Phillip Brannen Keith Delaplane Paul Gulliebeau Dan Horton Harold Scherm Plant Pathology Apiculture Safety Entomology Plant Pathology Steve McArtney Wayne Mitchem Mike Parker Bill Sullivan Turner Sutton David Tarpy Steve Toth Jim Walgenbach Horticulture Horticulture Horticulture Zoology Plant Pathology Entomology Entomology Entomology 1 Pest and Orchard Management Program DORMANT Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Control tree density, size, and shape for better light and spray penetration. Conduct annual dormant pruning in central leader trees and appropriate high-density orchards. ***** The younger the trees, the closer to bud break they should be pruned. Prune older and bearing trees first; prune 1- to 2-year-old nonbearing trees during the month before dormant bud break. Provide proper nutrition for moderate tree growth and good fruit quality. Collect soil samples; establish and maintain a good lime and fertility program. Apply late winter fertilizer to young, nonbearing trees, and half rate to mature, bearing trees. ***** See Fertility Management section (page 40) for complete sampling, fertilizer rates, and application methods. Apply full rate to young, nonbearing trees to promote good tree growth. Increase lateral bud break and lateral shoot development on last year's leader growth to encourage scaffold limb development. Bag last year's leader growth 3 to 4 weeks before anticipated dormant bud break. ***** See Growth-Regulating Chemicals section (page 61) for details. Plant Growth Regulators Control water sprout regrowth near pruning cuts and on tops of large scaffold limbs exposed to light by heavy dormant pruning. Tre-Hold A-112 See comments. Use 10,000 ppm (10 oz/gal) as a "sponge-on" application. 12 0 See Growth-Regulating Chemicals section (page 61) for complete recommendation details. The need for this practice depends on heaviness of pruning, size of cuts, and potential growth vigor. Effectiveness depends on COMPLETE coverage. Control burr knot formation. Gallex ** Paint directly from can, full strength, on burr knots. See Growth-Regulating Chemicals section (page 61) for recommendation details. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row volume of 400 gal/acre. 2 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Reduce inoculum of apple scab fungus. Shred leaves with flail mower. ***** May also help reduce inoculum of fungi that cause Brooks spot, Alternaria blotch, and Glomerella leafspot. Reduce inoculum of black, white, and bitter rot fungi. Prune out dead wood and mummied fruit. ***** Pruning is extremely important to reduce the likelihood of these diseases. Don’t stockpile prunings near orchard. Remove and burn, or chip with a flail mower. Reduce inoculum of fire blight bacteria. Prune out cankers and old fire blight strikes. **** Will also reduce inoculum of black rot, white rot, and bitter rot. Reduce inoculum of powdery mildew fungus. Prune out silver-colored terminals. *** Particularly useful on young trees of a susceptible cultivar. Improve control of cedar apple and quince rusts. Scout orchard, adjacent woods, or borders for red cedar, and remove. ***** Complete removal of red cedar in areas where cedars are not common may eliminate need for fungicide sprays for these diseases. Create good conditions for drying fruit and foliage; improve spray penetration. Prune to open trees. ***** Pruning is extremely important for good disease control inside the canopy and in the tops of large trees. Weed Management Control seedling perennials and winter annuals. Apply glyphosate or paraquat to control emerged winter annuals. ***** +++++ See product label. See product label. Apply nonselective postemergence herbicide alone (spring). When control from this breaks and summer weeds are 2-3 inches tall, apply a nonselective preemergence herbicide. This will likely be in early May, but may vary from year to year. Delaying PRE herbicide application results in residual control later in the summer. Reduce dandelions. 2,4-D amine ++++ 1 qt 1.0 lb 48 60 Apply at least 2 weeks before bloom to control flowering weeds. Reduces competition with apple blossoms to enhance bee pollination. Control of flowering weeds will also help control tarnished plant bug. 3 SILVER TIP Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control fire blight. Bactericides copper hydroxide copper oxychloride sulfate Bordeaux ++++ ++++ ++++ See label. See label. See label. See label. See label. See label. This treatment will help control fire blight in blocks of trees of a susceptible cultivar where fire blight has been a problem. It will not eliminate need for streptomycin. Applications later than 0.25- to 0.5-inch green tip may result in injury. Most effective if applied dilute. Control black rot. Fungicides Captan 50W or 4L ++++ ++++ —— 4 lb 2 qt 96 96 00 An important spray for black rot control in Georgia. Warning: Captan will cause injury when used with or too close to oil applications. Control crown rot (collar rot). Fungicides Ridomil Gold EC or WSP ++++ See label. 12 1 Ridomil and Aliette applications are recommended on cultivars propagated on susceptible rootstocks planted in heavy or poorly drained soils. Apply Ridomil in the spring before growth starts, and repeat application after harvest. Apply 3 to 5 applications of Aliette a year. Make first application of Aliette after leaf emergence. Note: Ridomil and Aliette must be applied on a preventive basis. Treatment of trees exhibiting symptoms will not prevent further symptom development. Aliette 80WDG or 80 WSP ++++ e to 1½ lb 2 to 5 lb 12 14 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 4 GREEN TIP TO ½-INCH GREEN Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate Per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab. See discussion in Fungicides and Bactericides (page 49) for information on postinfection control program. Fungicides Syllit 65 W +++++ ½ to ¾ lb 2 to 3 lb 48 7 Vangard 75WG +++++ 1.25 oz 5 oz 12 72 Vangard tends to be most active at cool temperatures. Vangard 75WG + mancozeb 80 WP or 75 DF or F4 or + Polyram 80DF +++++ +++++ +++++ +++++ +++++ ¾ oz ¾ lb ¾ lb 0.6 qt ¾ lb 3 oz 3 lb 3 lb 2.4 qt 3 lb 12 24 24 24 24 72 77 77 77 77 Scala SC +++++ 1.75 to 2.5 oz 7 to 10 oz 12 72 Scala SC is not compatible with captan. Scala SC + mancozeb 80 WP or 75 DF or F4 or + Polyram 80DF +++++ +++++ +++++ +++++ +++++ 1.25 oz ¾ lb ¾ lb 0.6 qt ¾ lb 5 oz 3 lb 3 lb 2.4 qt 3 lb 12 24 24 24 24 72 77 77 77 77 Sovran 50WG +++++ 1 to 1.6 oz 4 to 6.4 oz 12 30 Flint 50WG +++++ — 2 to 2.5 oz 12 14 Pristine 38W +++++ — 14.5 to 18.5 oz 12 0 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. GREEN TIP TO ½-INCH GREEN (Continued) 5 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate Per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Rubigan 1E + captan 50 WP or + mancozeb 80 WP or 75 DF or F4 or + Polyram 80DF +++++ +++++ +++++ +++++ +++++ 3 to 4 oz ¾ lb ¾ lb ¾ lb 0.6 qt ¾ lb 8 to 12 oz 3 lb 3 lb 3 lb 2.4 qt 3 lb 96 24 24 24 24 30 77 77 77 77 Do not use captan within 2 weeks of an oil spray. Although resistance of the apple scab fungus to the DMI fungicides Nova, Rubigan, and Procure has not been confirmed, some growers have experienced problems in the Southeast in controlling scab when using these fungicides. Growers who have had this problem should use a program that begins with two sprays of Syllit, Vangard, or Scala, followed by two sprays of Flint or Sovran. The fifth spray, which should occur around petal fall, can include a DMI fungicide, but it needs to be combined with a full rate of captan or captan + mancozeb or metiram to ensure scab control. A DMI fungicide at this time will help control powdery mildew, especially on mildew-susceptible varieties, and cedar apple and quince rust if captan is used alone. Nova 40W + captan 50 W or + mancozeb 80 W or 75 DF or F4 or + Polyram 80 DF +++++ +++++ +++++ +++++ +++++ 1¼ to 2 oz ¾ lb ¾ lb ¾ lb 0.6 qt ¾ lb 5 to 10 oz 3 lb 3 lb 3 lb 2.4 qt 3 lb 96 24 24 24 24 14 77 77 77 77 Procure 50WS + captan 50 W or + mancozeb 80 W or 75 DF or F4 or + Polyram 80W +++++ +++++ +++++ +++++ +++++ 1 to 2 oz ¾ lb ¾ lb ¾ lb 0.6 qt ¾ lb 4 to 8 oz 3 lb 3 lb 3 lb 2.4 qt 3 lb 96 24 24 24 24 14 77 77 77 77 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 6 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Insect Management Control scales and reduce overwintering European red mite and rosy apple aphid eggs. Improve scale and rosy apple aphid control Insecticides Oil Oil + Lorsban 4E or Supracide 2E or Esteem 35WP or Diazinon 50WP or Danitol 2.4EC or Asana XL or Ambush 2E or Warrior +++++ ++++ +++++ +++++ +++++ ++++ +++ +++ ++++ 2 gal 2 gal ½ to 1 pt 1 to 2 pt – 1.0 lb 2b to 5a oz 2 to 5.8 oz 1.6 to 3.2 oz 0.64 to 1.28 oz 8 gal 8 gal 2 to 4 pt 4 to 8 pt 4 to 5 oz 4 lb 10b to 21a oz 4.9 to 14.2 oz 6.4 to 12.8 oz 2.56 to 5.12 oz 12 12 96 12 12 24 24 12 12 24 0 0 DD DD 45 21 14 21 PF 21 Use a superior-type or highly refined summer oil applied dilute for best results. If the oil application is delayed until tight cluster to pink, use a refined oil or reduce a superior type to ½ to 1 gal/100 gal. Do not use captan within 2 weeks of an oil application. An insecticide with oil may be added at this time in orchards experiencing problems with scales or climbing cutworms. In some blocks, applications of Lorsban, Asana, and Ambush no longer control rosy apple aphid due to resistance. Neither Asana nor Ambush will control mites or scales. Note: Pyrethroids, including Asana, Ambush, Danitol, and Warrior will not control scales. These products are highly toxic to predatory mites and often lead to flare-ups of European red mite populations. Initiate Oriental Fruit Moth (OFM) monitoring program. Erect pheromone traps ***** Erect pheromone traps by green tip to detect first emergence. See section on IPM Practices for Selected Pests (page 29) for monitoring information. Mating disruption of OFM. Pheromones Isomate Rosso +++++ 100 dispensers /acre If insecticides are used for first generation OFM control at petal fall, mating disruption of OFM can be delayed until May or June. See section on “Mating Disruption” in IPM Practices for Selected Pests (page 31). 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. TIGHT CLUSTER TO PINK 7 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab. Fungicides Same fungicides as used in green-tip spray except do not use Vangard 75WG or Syllit 65W. If two sprays of Sovran or Flint have been used, switch to a nonstrobilurin fungicide. Control powdery mildew. Fungicides Nova 40W Rubigan EC Bayleton 50DF Procure 50WS +++++ ++++ ++++ +++++ 1¼ to 2 oz 3 to 4 oz ½ to 2 oz 1 to 2 oz 5 to 10 oz 8 to 12 oz 2 to 8 oz 4 to 8 oz 24 12 12 12 14 30 45 14 These are the most important sprays for the control of powdery mildew. Control cedar apple rust and quince rust. Fungicides Nova 40W Rubigan 1EC Bayleton 50DF mancozeb 80W or 75DF or F4 Polyram 80W Ferbam Granuflo +++++ +++++ +++++ +++++ +++++ +++++ +++++ ++++ 1¼ to 2 oz 3 to 4 oz ½ to 2 oz ¾ lb ¾ lb 0.6 qt ¾ lb ½ lb 5 to 10 oz 8 to 12 oz 2 to 8 oz 3 lb 3 lb 2.4 qt 3 lb 2 lb 24 12 12 24 24 24 24 24 14 30 45 77 77 77 77 7 Do not use Ferbam within 7 days of an oil spray. Control black rot and frogeye leafspot. Captan 50W or 4L ++++ ++++ 1 ½ to 2 lb ¾ to 1 qt 6 to 8 lb 3 to 4 qt 96 96 00 Captan alone will not control powdery mildew or rust diseases. Insect Management Initiate codling moth and leafroller monitoring program. Erect pheromone traps. ***** Erect traps now because moths begin to emerge near bloom. See section on IPM Practices for Selected Pests (page 29) for information on monitoring programs. 8 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv Interval 100 gal Acre (days) Comments Insect Management Control rosy apple aphid. Insecticides Actara 25WDG Assail 30SG Calypso 4F Thiodan 3EC, Phaser 3EC Diazinon 50W Dimethoate 4EC/400 Danitol 2.4EC +++++ +++++ +++++ +++ ++++ ++++ +++++ – – – b qt 1 lb ½ to 1 pt 2.6 to 4.3 oz 4.5 oz 2.5 to 4 oz 2 to 4 oz 2 b qt 4 lb 2 to 4 pt 10.6 to 21.3 oz 12 12 12 24 24 24 24 35 7 30 21 21 28 14 Pink stage is the best time to control rosy apple aphid. Caution: Rosy apple aphid resistance to Thiodan, Diazinon, Dimethoate, and Danitol has been observed in some orchards. See Rosy Apple Aphid resistance section (page 35). Assail may be used during bloom if sprays are applied before or after bees are in the orchard. Assail residues on leaves or flowers are not toxic to bees, but avoid spraying when bees are in the orchard. Control plant bugs and spotted tentiform leafminer (STLM). Maintain clean ground-cover. Insecticides listed for rosy apple aphid will aid in plant bug and leafminer control if plant bugs are readily seen. ***** In many instances, a clean groundcover eliminates the need for insecticides to control bugs. If there is a history of plant bug problems, a second application at petal fall will improve control. The need for insecticides specifically targeting STLM at this time is questionable because first generation mines rarely exceed threshold levels. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 9 BLOOM Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Loosen bags on leaders to acclimate for 2 to 3 days; then remove bags from leaders and spray with Promalin. Leader bags must be removed when new lateral growth is 1 to 3" long. ***** See Growth-Regulating Chemicals section (page 61) for complete details. Do leader selection and strip whorl on dormant headed tree leaders. Select new shoot for central leader and remove competing shoots from first four nodes below new leader shoot. Plant Growth Regulators Improve fruit shape and increase fruit weight of Red and Golden Delicious (can be used only on varieties that have dominant calyx ends). (BA+GA 4 + 7) Promalin Perlan +++ +++ 1 to 2 pt 1 to 2 pt 12 4 None See Growth-Regulating Chemicals section (page 61). Apply as a fine mist application at 40 to 50% of Tree Row Volume (TRV) water rate between king bloom opening and full bloom. Increase lateral bud break and lateral shoot growth on 1-year-old leader growth as a tool to encourage scaffold limb development, especially on those that were bagged before bud break. Promalin Perlan +++++ +++++ 250 to 500 ppm (1 to 2 pt)/10 gal 125 to 500 ppm (0.5 to 2 pt)/ 10 gal 12 4 None Apply to last year's leader growth with a handheld nozzle. See Growth-Regulating Chemicals section (page 61). Make one application when orchard trees have 1 to 3 inches of new growth. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 10 Goals Options Relative1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab, rusts, and mildew. Fungicides Same fungicides as recommended in tight cluster stage. Avoid sprays in full bloom if possible. Do not overextend application intervals. Control fire blight. Bactericides streptomycin 4.8 to 8 oz 1½ to 2½ lb 12 50 Begin application at first bloom and continue at 3- to 4-day intervals until petal fall. Streptomycin sprays protect only those blossoms open at time of application. It is very important to continue spraying through “rat-tail” bloom, especially on susceptible varieties. See discussion under Resistance Management section (page 34) for timing sprays according to conditions favorable for infection. Insect Management Protect pollinators. Do not apply insecticides during bloom. ***** Keep orchard floor free of flowering weeds. This will increase pollination activity in the trees and lessen bee activity after apple bloom. Disrupt mating of codling moth. Pheromones Isomate CTT CheckMate CM-XL 1000 ++++ ++++ (# dispensers) 200/acre 120-200/acre Do not use mating disruption in blocks of less than 5 acres. Pheromone dispensers should be hung before moths begin to emerge, with hanging completed by petal fall. Also, supplemental sprays with an insecticide may be necessary under moderate to high population densities. See section on IPM Practices for Selected Pests (page 29). 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. PETAL FALL 11 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Reduce fruit corking. Solubor +++ 1 lb at first cover If boron is low in leaf sample or cork spot has been a problem in past years, a second and third application may be used. Dilute applications are necessary for good uptake. See Fertility Management section (page 40). Reduce fruit corking and bitter pit. calcium nitrate or calcium chloride +++ +++ 3 lb 2 lb beginning at first cover Repeat calcium sprays in each cover spray all season. Calcium nitrate may contribute to unwanted leaf nitrogen levels and vegetative growth. Do not apply calcium chloride when temperatures are above 85ºF, and DO NOT tank mix with Solubor. All calcium sprays should be applied dilute for maximum response, especially for bitter pit control in the late season cover spray when fruit are becoming waxy. See Fertility Management section (page 40). Plant Growth Regulators Reduce fruit russetting on susceptible cultivars (esp. Golden Delicious). (GA4+7) Pro-Vide Novagib ++++ ++++ 10 oz/appl. 20-26 oz/appl. 12 4 None At petal fall, begin the first of four applications at 10-day intervals. See Growth-Regulating Chemicals section (page 61) for complete recommendations. Thin fruit to reduce crop load and encourage return bloom. Depends on cultivar, fruit size, and thinning chemical selected. Applications timed from petal fall to about 8 mm would be applied during this time. +++++ See Thinning Chart. Check label for specific thinning chemical(s) to be used. See Chemical Fruit Thinning Spray and Apple Thinning recommendations chart in Growth- Regulating Chemicals section (page 64). Initiate vegetative growth control applications. Apogee ++++ Use at TRV calculated A.I./acre. 12 45 See Apogee table in Growth-Regulating Chemicals section (page 66). 12 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab. Scout for secondary scab. ***** If primary scab is controlled by petal fall or first cover, switch to captan. If secondary scab is detected early, dodine, Rubigan, Nova, or Procure can be effectively used in a postsymptom treatment. See discussion under Fungicides and Bactericides (page 49). Control summer diseases (general). Fungicides captan 50W or 4L 2 lb 1 qt 8 lb 4 qt 96 96 0 0 If Rubigan, Nova, or Procure is used in this spray, increase the rate of Captan 50W to 6 to 8 lb/acre or Captan 4L to 3 to 4 qt/acre and extend interval to 10 to 14 days, or follow combination sprays with lower rates of captan or metiram in 5 to 7 days with full rate of captan or combinations of captan plus mancozeb or metiram. Captan and metiram at petal fall or first cover generally give better fruit finish than mancozeb. If the first cover spray occurs after May 15, include 8 to 12 oz/acre of Topsin M70WP with captan for sooty blotch or flyspeck control as directed in second and later cover sprays below. Use captan in orchards where black rot is a problem. captan 50W or 4L + Polyram 80 W or mancozeb 80W 75 DF 4F +++++ +++++ +++++ +++++ +++++ 1¼ lb 0.62 qt ¾ lb ¾ lb ¾ lb 0.6 qt 5 lb 2½ qt 3 lb 3 lb 3 lb 2.4 qt 96 96 96 96 77 77 77 77 Sovran 50WG +++++ 1.0 to 1.6 oz 4.0 to 6.4 oz 12 30 Sovran and Flint will also control apple scab and powdery mildew. PETAL FALL (continued) 13 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control summer diseases (general) (continued). Flint 50WG +++++ — 2.5 to 3.0 oz 12 14 Pristine 38W +++++ — 14.5 to 18.0 oz 12 0 Control Brooks fruit spot. Fungicides Use fungicides listed for summer diseases or use fungicide combinations listed under green tip. +++++ Petal fall through third cover sprays are the most important sprays for Brooks spot control. Nova, Rubigan, and Procure have very little Brooks spot activity. If Nova, Rubigan, or Procure are used, combine them with a full rate of protectant. Control powdery mildew. Fungicides Bayleton 50DF +++++ 0.5 to 2 oz 2 to 8 oz 12 45 If Nova, Rubigan, or Procure are no longer used, include Bayleton for mildew control on susceptible cultivars. Control cedar apple rust. Fungicides Ferbam Granuflo ++++ ½ lb 2 lb 24 7 If captan alone is used in these sprays, include Ferbam where cedar apple rust is a problem. Insect Management Preventively control European red mite, spotted tentiform leafminer, and white apple leafhopper. Control European red mite. Insecticides Agri-Mek 0.15EC + oil Apollo SC Savey 50WP Zeal 72WDG FujiMite5EC Envidor 2SC +++++ +++++ +++++ +++++ +++++ ++++ 2.5 oz S S S S S 10 oz 4 oz 3 oz 2 to 3 oz 1 to 2 pt 16 to 18 oz 12 12 12 12 12 12 28 45 28 28 14 7 An application of Agri-Mek at petal fall should provide season-long suppression of these pests. A paraffinic spray oil (0.25% or 1 gal/acre) must be tank mixed to ensure Agri-Mek’s activity. Do not use captan 2 weeks before or after applying oil with Agri-Mek. Apollo and Savey are most effective if applied at petal fall or first cover. Apply FujiMite, Zeal, or Envidor between petal fall and third cover or when mites reach one adult per leaf. FujiMite will also control leafhoppers. See page 35 for resistance management of European red mite. 14 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control plum curculio. Insecticides Guthion 50WP Imidan 70WP Avaunt 30WG Actara 25SDG Assail 30SG Calypso 4F Clutch 50WDG Sevin 50WP +++++ +++++ +++++ +++++ ++++ ++++ +++ ++++ ½ lb ¾ lb – – – 1 to 2 oz – ½ lb 2 lb 3 lb 5 to 6 oz 4.5 to 5.5 oz 8 oz 4 to 8 oz 3 oz 1 lb 48h, 14d 24 12 12 12 12 12 12 21 7 28 35 7 30 14 3 Adults enter orchards before or near petal fall. A preventive spray is recommended to minimize damage on fresh market apples. Cool weather during this period may extend adult activity, which may require a second application. Read about re-entry interval for Guthion in the Insecticides and Miticides section (page 52). Control Oriental fruit moth. Insecticides Guthion 50WP Imidan 70WP Avaunt 30WG Sevin 50WP Assail 30SG Calypso 4F Clutch 50WDG +++++ +++++ ++++ ++++ ++++ ++++ +++ ½ lb ¾ lb – ½ lb – 1 to 2 oz – 2 lb 3 lb 5 to 6 oz 2 lb 5 to 8 oz 4 to 8 oz 3 oz 48h, 14d 24 12 12 12 12 12 21 7 28 3 7 30 14 Oriental fruit moth has become more important in apples in recent years. An insecticide applied between 500 and 600 degree days (DD) after biofix will control the first generation. Read about re-entry interval for Guthion in Insecticides and Miticides Section (page 52). Control San Jose scale. Insecticides Dimethoate 4EC/400 Diazinon 50WP Guthion 50WP Esteem 0.86EC Centaur 70WP Assail 30SG summer oil +++++ +++++ ++++ +++++ ++++ ++++ +++ ½ to 1 pt 1 lb ½ lb – – – – 2 to 4 pt 4 lb 2 lb 4 oz 34.5 oz 8 oz 1 to 2% 48 24 48h, 14d 12 12 12 12 28 21 21 45 14 7 0 Where scales are a problem, apply an insecticide for first generation crawlers, which are active from petal fall through third cover. Yellow crawlers can be detected by wrapping double-stick tape around infested limbs after bloom and inspecting weekly. Caution: Diazinon or oil applied with captan or Captec may cause phytotoxicity. Control white apple leafhopper. Insecticides Sevin 50WP Actara 25WDG Assail 30SG Calpyso 4F Provado 1.6F Avaunt 30WG +++++ +++++ +++++ +++++ +++++ +++++ ½ lb – – 0.5 to 1 oz 1 oz – 2 lb 2 to 2¾ oz 2.5 to 4.0 oz 2 to 4 oz 4 oz 5 to 6 oz 12 12 12 12 12 12 1 35 7 30 7 28 Threshold level for first generation white apple leafhopper is 1 nymph per leaf. Thinning apples with Sevin during this time controls leafhoppers. Leafhoppers may be present from petal fall to second cover spray. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 15 PETAL FALL (continued) Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control spotted tentiform leafminer. Insecticides Lannate 90SP Actara 25WDG Provado 1.6F SpinTor 2SC Assail 30SG ++++ ++++ ++++ +++++ ++++ ¼ lb – 1 to 2 oz – – 1 lb 4.5 oz 4 to 8 oz 5 to 8 oz 1.1 oz 72 12 12 4 12 14 35 7 7 7 Threshold level for first generation leafminer is one mine per leaf, but rarely do populations reach this level this early in the season. Control rosy apple aphid. Insecticides Provado 1.6F Actara 25WP Assail 30SG Calypso 4F Dimethoate 4EC/400 Danitol 2.4EC +++++ +++++ +++++ +++++ ++++ ++++ 2 oz 4.5 oz – 0.5 to 1.0 ½ pt 2.6 to 5.3 oz 4 to 8 oz 4.5 oz 2.5 to 4.0 oz 2 to 4 oz 2 pt 10.6 to 21.3 oz 12 12 12 12 48 24 7 35 7 30 28 14 If an insecticide was not applied for rosy apple aphid at pink, or if control was poor, an insecticide should be applied. Caution: Diazinon applied with captan or Captec may cause phytotoxicity or russetting. Control green fruitworm. Insecticides Guthion 50WP Imidan 70WP +++++ +++++ ½ lb ¾ lb 2 lb 3 lb 48h, 14d 24 21 7 Green fruitworms are not a common pest: Apply an insecticide at petal fall if larvae are observed. Weed Management Control weeds. Check orchards for weed populations. ***** Identify weed problems so herbicide program can be adjusted for summer weed control. Apply Pre + Post herbicide. See herbicide guide. ***** See product labels. See product labels. Apply when summer weeds are 2 to 3 inches tall. Delaying application of preemergence herbicides until early May extends summer weed control. Suppress clover bloom to protect bees from insecticide sprays. 2,4-D ***** 1 qt 48 60 Apply 2,4-D 7 to 10 days before spraying insecticides to suppress clover and avoid killing bees. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 16 FIRST COVER Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management (Same fungicides as used in Petal Fall Spray) Insect Management Control codling moth. Monitor codling moth adult activity. Insecticides Guthion 50WP Imidan 50WP Intrepid 2F Rimon Danitol 2.4EC Esteem 35WP Assail 30SG Calypso 4F CYD-X ***** +++++ +++++ +++++ +++++ +++++ +++ ++++ ++++ ++++ ½ lb ¾ lb – – – – – 1 to 2 oz – 2 lb 3 lb 10 to 16 oz 20 to 40 oz 16 to 21a oz 4 to 5 oz 4 to 8 oz 4 to 8 oz 1 to 3 oz 48h, 14d 24 4 12 24 24 12 12 4 21 7 14 14 14 45 7 30 0 See IPM Practices for codling moth (page 29) to determine how to minimize insecticide applications for codling moth control. Most insecticides generally provide 2 weeks’ control, so do not be concerned if pheromone trap counts remain high 1 week after spraying. If using Intrepid, Rimon, or Esteem for first generaton codling moth, 2 applications at 14- day intervals should be made, the first at 100- 200 DD. Do not make more than 2 applications of Esteem per season. CYD-X is a virus that controls only codling moth. Frequent applications (7-14 days) at low rates (1 to 2 oz per acre) have worked well in field trials. Control rosy apple aphid, plum curculio, white apple leafhopper, spotted tentiform leafminer, and San Jose scale. Monitor orchards for these insects. Insecticides (See Petal Fall section, page 11) ***** Infestations of these insects may occur anytime from petal fall to the second cover spray. Early detection is important for effective control. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 17 SECOND COVER AND LATER SPRAYS Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Reduce fruit corking and bitter pit. calcium nitrate calcium chloride +++ +++ 3 lb 2 lb See information listed in Petal Fall to First Cover sections (pages 11 through 16) and Fertility Management section (page 40). Provide proper nutrition for moderate tree growth and good fruit quality. Apply second half of fertilizer to mature, bearing trees if crop load is present, as soon as frost/freeze danger is past (approx. second cover). Collect leaf samples in July to mid-August for leaf analysis. ++++ +++++ See Fertility Management Recommendations section (page 40) for fertilizer use suggestions and complete recommendations. See Fertility Management Recommendations section (page 40) for complete details. Achieve proper tree training, and control tree size and density for good light and spray penetration. Select lateral limbs, strip whorls, establish wide crotch angles with toothpicks or clothespins, and prop limbs to good limb angles (60-90º for central leader trees and 75-85º below vertical for high density, slender, spindle-type trees). Do detailed young tree management (deshoot, position limbs, tie up leader growth) every 6 to 8 weeks until full tree size and bearing are achieved (especially for high density orchards). ++++ ++++ Tree training is mandatory to develop proper lateral branching and limb position. Summer pruning is a necessary extension of tree training begun earlier. Summer pruning helps contain tree size and density, and proper limb selection and positioning encourage flower initiation. Remove water sprouts. Do leader manipulation, such as summer bending or snaking, every 18 inches of terminal growth extension. ++++ ++ Removing upright water sprout growth reduces tree density, allowing greater spray penetration and better light distribution for fruit quality and color development. Summer pruning and removal of water sprouts also help control sooty blotch and flyspeck. 18 Goals Options Relative 1 Effectiveness(+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Plant Growth Regulators Thin to reduce crop load and encourage return bloom. Depends on cultivar, fruit size, and thinning chemical selected. Application time from approximately 9 mm and larger would be applied from second cover on. +++++ See thinning chart. See Chemical Fruit Thinning Sprays (page 62) and Apple Thinning Recommendations chart (page 64) in Growth-Regulating Chemicals section. Enhance return bloom. Naphthaleneacetic acid (NAA) +++ See NAA Table in PGR Section (page 65). Control ground suckers around base of trunk. Tre-Hold A-112 Sprout Inhibitor Also use herbicides approved for sucker control. See comments in Herbicide section (page 59) for Rely, Gramoxone. ++++ Use 10,000 ppm (10 oz/1 gal) as a low-pressure, large-droplet handgun application. 12 0 See Growth-Regulating Chemicals (page 66) for specific recommendation details. Delay preharvest fruit drop and delay fruit maturity. ReTain +++++ 2 oz One 333- gram pouch per acre (50 grams a.i.). 12 21 Apply a single application 4 weeks before normal start of harvest for each variety. Fruit maturity and harvest date will be significantly delayed. See Growth-Regulating Chemicals (page 67) for recommendation details. Delay or reduce preharvest fruit drop or both. Preload NAA (Fruitone-N) ++++ 2 oz 4 days 4 Apply multiple applications of 5 ppm each week for the 4-week period prior to the normal start of the harvest period for each variety. NAA + 4 to 8 oz 4 days 4 Temporarily suppress any fruit drop by applying 10 to 20 ppm (depending on variety) of NAA. A second application can be applied 7 to 10 days later. See Growth-Regulating Chemicals section (page 67) for recommendation details. SECOND COVER AND LATER SPRAYS (continued) 19 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Reduce fruit russetting in susceptible varieties. Pro-Vide 10SG Novagib (continue applications started at petal fall) ++++ ++++ 60-100 g 20 oz per acre/appl 12 4 0 See Petal Fall to First Cover sections and Growth-Regulating Chemicals section (page 61) for recommendation details. Reduce fruit cracking of susceptible varieties (e.g., Stayman). Pro-Vide 10SG +++ 100-200 g 12 0 Begin applications in early to mid-June or as soon as cracking is observed. Repeat at 3-week intervals until harvest. See Growth- Regulating Chemicals section (page 61) for details. Novagib +++ 2 to 4 pt per acre/appl 4 Promote lateral branching of current season’s growth. Promalin +++ 0.8 oz/gal of water (125 ppm) 12 None See Growth-Regulating Chemicals section (page 61) or recommendation details. Disease Management Control summer diseases (white rot, bitter rot, black rot, sooty blotch, flyspeck, black pox). Scout orchard. Prune out fire blight strikes. ***** ***** Apply cover sprays at 10- to 14-day intervals. Use a 10-day interval during wet, rainy periods. If Topsin M is not used in cover sprays, it is important to combine captan with sufficient ziram to increase fungicide rate to 8 to 10 lb/acre in order to control sooty blotch and flyspeck. Be sure to observe 77-day preharvest interval when using metiram or mancozeb. When using a combination of captan and ziram, use approximately equal rates of each. Use captan where there is a history of white rot. Fungicides captan 50W 4L +++++ +++++ 2 lb 1 qt 8 lb 4 qt 96 96 0 0 ziram 76DF or 76WDG ++++ 2 lb 8 lb 48 14 Thiram 65W ++++ 1.7 lb 6.8 lb 24 0 Sovran 50WG +++++ 1.0 to 1.6 oz 4.0 to 6.4 oz 12 30 A maximum of four applications and 25.6 oz of Sovran 50WG can be used per acre per season. It is weak on black pox. Flint 50WG +++++ – 2.5 to 3.0 oz 12 14 A maximum of four applications and 11 oz of Flint 50WG can be used per acre per season. It is weak on black pox. 20 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control summer diseases (continued). Pristine 38W +++++ – 14.5 to 18.0 oz 12 0 A maximum of four applications and 72 oz of Pristine can be used per acre per season. Pristine has activity on strains of the Alternaria blotch fungus that are resistant to Sovran and Flint. It is weak on black pox. captan 50 W 4L + Topsin M70WP +++++ 2 lb 1 qt 2 to 3 oz 8 lb 4 qt 8 to 12 oz 96 1 ziram 76DF or 76WDG + Topsin M70WP +++++ 2 lb 2 to 3 oz 8 lb 8 to 12 oz 48 14 thiram 75WDG + Topsin M70WP +++++ 2 lb 2 to 3 oz 8 lb 8 to 12 oz 24 0 captan 50 W 4L + metiram 80DF or mancozeb 75DF + Topsin M70WP +++++ 2 lb 1 qt ¾ lb ¾ lb 2 to 3 oz 8 lb 4 qt 3 lb 3 lb 8 to 12 oz 96 77 77 77 Metiram and mancozeb cannot be used within 77 days of harvest. captan 50 W or 4 L + ziram 76DF, 76WDG or thiram 65WDG + Topsin M70WP +++++ 1 lb ½ qt 1 lb 1 lb 2 to 3 oz 4 lb 1 qt 4 lb 4 lb 8 to 12 oz 96 14 If thiram is used in this combination, the REI is 96 hours and the PHI is 0 days. Suppress necrotic leaf blotch on Golden Delicious. ziram 76W or WDG thiram 75WDG zinc oxide 39.8% +++++ ++++ +++++ 1 to 2 lb 1 to 2 lb 4 to 8 lb 4 to 8 lb 1 pt 48 24 0 14 0 0 Sprays from mid June through early August are most important. SECOND COVER AND LATER SPRAYS (continued) 21 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control powdery mildew. Scout orchard. ***** Determine need for additional fungicides based on the number of infections on newly unfolded leaves. Control Alternaria blotch. Sovran 50WG Flint 50WG +++++ +++++ 1 to 1.6 oz 4 to 6.4 oz 2.5 to 3 oz 12 12 30 14 Make first application of Flint or Sovran around third or fourth cover (mid June). Apply two additional applications at 10- to 14-day intervals. These applications will also control other summer diseases on Delicious. Use in conjunction with a preventive mite management program. Insect Management Control codling moth. Monitor pheromone traps weekly for adult activity. Insecticides (See First Cover.) ***** See IPM practices for codling moth (page 29) and Oriental fruit moth (page 30) to determine the need for and timing of insecticide sprays. Insecticides provide 2 weeks’ control, so do not be concerned if trap catches remain high 1 week after spraying. Keep trap bottoms clean, and replace lures monthly. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 22 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. interval 100 gal Acre (days) Comments Control Oriental fruit moth. Monitor pheromone traps weekly for adult activity. Insecticides Guthion 50WP Imidan 70WP Intrepid 2F Rimon 0.83EC Danitol 2.4EC Assail 70WP Calypso 4F Mating Disruption Isomate-M100 Isomate Rosso CheckMate OFM-F ***** +++++ +++++ ++++ +++++ +++++ ++++ ++++ +++++ +++++ +++++ ½ lb ¾ lb – – – – 1 to 2 oz 2 lb 3 lb 12 to 16 oz 20 to 40 oz 5 to 6 oz 1.7 to 3.4 oz 4 to 8 oz 100 160 0.3 to 2.5 oz 48h, 14d 24 4 12 12 12 12 21 7 14 14 28 7 30 See IPM practices for Oriental fruit moth (page 30) to determine the need for and timing of insecticide sprays. Oriental fruit moth has become more important on apples in recent years, particularly later generations in August and September. Under moderate to low OFM populations, pheromone treatment should begin just before emergence of third generation adults (late June to early July). When OFM populations are high, begin mating disruption just before emergence of second generation adults (late May to early June). Control tufted apple bud moth. Monitor pheromone traps weekly for adult activity. Thin fruit to avoid excessive clustering. ***** **** See IPM Practices for tufted apple bud moth (page 31) to determine the proper timing of insecticide applications. Clustering of fruit is conducive to higher levels of tufted apple bud moth injury. Insecticides Intrepid SpinTor 2SC Danitol 2.4EC Avaunt 30WDG Rimon 0.83EC +++++ +++++ +++++ ++++ ++++ – – – – – 6 to 12 oz 4 to 8 oz 10.6 to 21.3 oz 5 to 6 oz 20 to 40 oz 4 4 24 12 12 14 7 14 28 14 See Insecticide Resistance Management section (page 35) for tufted apple bud moth (TABM). Insecticide sprays for TABM are recommended only in orchards with a history of damage. See section on IPM practices for tufted apple bud moth to properly time sprays. Bacillus thuringiensis Dipel 2X CryMax XenTari +++ ¼ to ½ lb ¼ to ½ lb ¼ to ½ lb 1 to 2 lb 1 to 2 lb 1 to 2 lb 4 4 4 0 0 0 For best results apply Bacillus thuringiensis (Bt) products at no less than 2X concentration. If using Bts, it is important to monitor codling moth with pheromone traps because Bts do not control codling moth. SECOND COVER AND LATER SPRAYS (continued) 23 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control apple maggot. Erect red sticky spheres in early June to monitor adults. **** Apple maggot has increased in importance in recent years and is particularly a problem in orchards near unsprayed orchards and/or following a year in which many orchards did not receive a full-season spray program, but still had some fruit in the orchard. Erect sticky traps on outside rows nearest abandoned orchards or other sources of flies. Check weekly. Threshold level is one fly per trap per week. If flies are still caught 2 weeks after spraying, apply again. Adults can emerge from June through August. Insecticides Guthion 50WP Imidan 70WP Assail 30SG Calypso 4F Clutch 50WDG Provado Surround WP +++++ +++++ ++++ ++++ ++++ +++ +++ ½ lb ¾ lb – 1 to 2 oz – – – 2 lb 3 lb 8 oz 4 to 8 oz 6 to 8 oz 4 to 8 oz 20 to 50 lb 48h, 14d 24 12 12 12 12 4 21 7 7 30 14 7 – Apply insecticides at 10- to 14-day intervals during apple maggot flight. Apply Surround at 7- to 14-day intervals, or after a heavy rain, because thorough, uniform, and consistent coverage is important. Rate of Surround will vary with tree size. Control white apple leafhopper or potato leafhopper. Insecticides Provado 1.6F Actara 25WDG Assail 30SG Calypso 4F Avaunt 30WG Dimethoate 4EC/400 Clutch 50WDG Centaur 70WP +++++ +++++ +++++ +++++ +++++ +++ +++++ +++++ 1 oz – – 0.5 to 1 oz – ½ pt – – 4 oz 2 to 2¾ oz 2.5 to 4.0 oz 2 to 4 oz 5 to 6 oz 2 pt 2 oz 34.5 oz 12 12 12 12 12 48 12 12 7 14 7 30 28 28 14 14 Threshold level for second brood nymphs (which occur in late July to early August) is one nymph per leaf. Treatment will eliminate the need to treat for adults immediately before harvest. Generally, low rates of insecticides will control leafhoppers. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry interval (hours) Preharv. interval 100 gal Acre (days) Comments 24 Control spotted tentiform leafminer. Insecticides Lannate 90SP SpinTor 2SC Vydate 2L Provado 1.6F Actara 25WDG Assail 30SG Calypso 4F Clutch 50WDG ++++ +++++ ++++ +++ ++++ ++++ ++++ ++++ ¼ lb – 1 to 2 pt 2 oz – – 0.5 to 1 oz – 1 lb 4 to 8 oz 4 to 8 pt 8 oz 4.5 oz 2.5 oz 2 to 4 oz 3 oz 72 4 48 12 12 12 12 12 14 0 14 7 14 7 28 14 A threshold level of two mines per leaf for second generation larvae (June to July) should be used to dictate the need for STLM control. Control of third generation larvae (August) may be necessary on late-maturing cultivars if populations exceed 4 mines per leaf. Many orchards have high levels of parasites by this time. Insecticides are more effective against sap-feeding mines than tissue feeders. Control green apple and spirea aphids. Insecticides Dimethoate 4EC/400 Provado 1.6F Actara 25WDG Assail 30SG Calypso 4F Clutch 50WDG +++++ +++++ +++++ +++++ +++++ +++++ ½ pt 1 to 2 oz –– 0.5 to 1 oz – 2 pt 4 to 8 oz 4.5 oz 2.5 to 4.0 oz 2 to 4 oz 2 oz 48 12 12 12 12 12 28 7 35 7 28 14 Threshold level for green apple aphid is 50% infested terminals. Control is most important on young trees and in dwarf plantings. On mature trees, a higher threshold is tolerable. Control Comstock mealybug. Insecticides Diazinon 50WP Dimethoate 4EC Actara 25WDG Assail 30SG +++++ +++++ +++ +++++ 1 lb ½ pt –– 4 lb 2 pt 4.5 oz 4 to 8 oz 24 48 12 12 14 28 35 7 Applications should be made near the third cover spray. Comstock mealybug has become a problem in some orchards where organophosphate use has been reduced or eliminated, where postbloom pyrethroid use has increased, or both. Control woolly apple aphid. Insecticides Dimethoate 4EC/400 Diazinon 50W +++ +++ ½ pt 1 lb 2 pt 4 lb 48 24 28 21 In recent years woolly apple aphid has increased in many areas. Above-ground infestations are of greatest concern on younger trees. Control redbanded leafroller. Insecticides Bacillus thuringiensis Guthion 50WP Imidan 70WP Intrepid 2F SpinTor +++ ++++ ++++ +++++ +++++ ¼ lb ½ lb ¾ lb – – 1 lb 2 lb 3 lb 8 to 10 oz 4 to 8 oz 12 48h, 14d 24 4 4 0 21 7 14 7 Redbanded leafroller is a sporadic problem. If damage is done, it is usually by the last generation, which lays eggs from mid August to mid September. Control lesser apple worm. Insecticides Guthion 50WP Imidan 70WP Intrepid 2F +++++ +++++ +++++ ½ lb ¾ lb – 2 lb 3 lb 10 to 16 oz 48h, 14d 24 4 21 7 14 Lesser apple worm is a sporadic pest of importance in isolated areas. If damage occurs, it is usually by the third generation, which occurs in August. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. SECOND COVER AND LATER SPRAYS (continued) 25 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control dogwood borer. Insecticides Lorsban 50W, 4E Thiodan 3EC Asana XL ++++ +++++ +++ +++ 3 lb 1.5 qt a qt 2.0 to 5.8 oz – – – – 96 96 24 24 28 28 21 21 Apply insecticides with a handgun sprayer to the trunk, especially to burr knots and graft unions. Moths can lay eggs from mid May through July, so treatment in mid to late May is optimal. Lorsban should be applied with a handgun sprayer from no more than 4 ft or with a shielded sprayer to prevent drift onto foliage or fruit. Control European red mite and two-spotted spider mite. Monitor trees for mite activity. ***** See IPM practices for European red mite. European red mite and two-spotted spider mite threshold levels before July are 7 mites per leaf (85% infested leaves) and 10 mites per leaf (90% infested leaves) during July and August. If populations are near threshold level and Stethorus punctum is present, recheck in 3 to 4 days to determine if biological control reduces mite populations. In orchards with Alternaria blotch, a threshold of 2 mites per leaf (70 to 75% infested leaves) should be used to minimize stress to trees. Miticides Acramite 50WS Nexter 75WP Apollo SC Savey 50DF Zeal 72WDG Envidor 2SC Kelthane 50WP Vendex 50W Danitol 2.4EC wettable sulfur summer oil +++++ +++++ +++++ +++++ +++++ +++++ ++++ ++++ ++++ + ++ – – – – – – ¾ to 1½ lb ¼ lb – 1 ½ to 3½ lb ½ to 1 gal ¾ to 1 lb 4.4 oz 4.0 oz 3.0 oz 2 to 3 oz 16 to 18 oz 3 to 6 lb 2 lb 16 to 21.6 oz 5 to 15 lb ½ to 1% soln. 12 12 12 12 12 12 12 48 24 12 12 7 25 45 28 28 14 7 14 14 7 0 If Apollo or Savey were used at petal fall, do not reapply at this time. Use the higher rate of Kelthane on large trees. Do not expect complete control with a single application of oil or sulfur. These materials must be applied multiple times for best results. Applying a highly refined summer oil when mite populations are beginning to increase (first and second covers) will help suppress European red mite infestations. Do not apply captan 2 weeks before or after an oil spray. SECOND COVER AND LATER SPRAYS (continued) 26 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Weed Management Spot-treat with herbicide to control difficult-to-manage perennial weeds. glyphosate ***** See Weed Response to Herbicide table (pages 46 to 48). Apple trees are especially sensitive to glyphosate applied in late summer and fall. Avoid contacting tree bark and especially foliage. . POSTHARVEST Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Plant Growth Regulators Control fruit storage scald. DPA ++++ 2½ pt per one gal of water as a dip or spray to harvested fruit. See Growth-Regulating Chemicals section (page 61) for complete details. To maintain apple flesh firmness, fruit acidity and minimize scald SmartFresh See Growth-Regulating Chemicals section (page 61) for complete details. Weed Management Apply POST or PRE + POST herbicide. See herbicide guide. *** See herbicide guide. See product labels. In areas where heavy populations of winter annual weeds are present, apply herbicide as part of vole management program. Application of a fall preemergence herbicide will delay the spring herbicide application to early May or later. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 27 Tree Row Volume (TRV): A Model for Determining Spray Volume The TRV model is a simple and objective method of determining (1) the volume of tree canopy on an acre of orchard, regardless of row spacing, tree size, age, or other factors; and (2) the dilute application water rate and chemical quantity for dilute (1X) applications or concentrate chemical load per acre needed to effectively spray each particular orchard, regardless of pruning and tree canopy density. The TRV concept rests on these assumptions: Each row of trees is a wall of foliage, and water and chemical loads required can be related to the volume and density of foliage within that wall. Only three measurements must be made: (1) The distance between rows of trees; (2) the maximum tree height to be sprayed; and (3) the spread from drip line to drip line, which must be accurately measured to at least the nearest foot. In addition, an assessment of tree density is needed to calculate the TRV of an orchard. Using these measurements, the TRV of any orchard can be calculated using the following formula: Step 1: 43,560 sq ft/acre = feet of row/acre distance between rows (ft) Step 2: Feet of row/acre (from Step 1) X tree height (ft) X cross-limb spread (ft) = cu ft of foliage/acre. Steps 1 and 2 determine the volume of foliage canopy per acre in the orchard. Step 3: Select one of the numbers from Table 1 that best indicates the canopy density of each separate orchard or block. The cubic feet of foliage volume from Step 2 and the tree density established in Step 3 are used to calculate the water volume required per acre for a dilute spray application to provide maximum chemical load with a dilute airblast sprayer (applied to runoff). canopy Step 4: cu ft of foliage/acre density gallons of dilute solution (from Step 2) X (from Step 3) = to be applied per acre for 1,000 cu ft a maximum application Example Consider an orchard that has rows spaced 25 feet apart, trees 20 feet high, a spread of 17 feet from drip line to drip line, and a tree density of 0.85. Step 1: 43,560 ft2 25 ft = 1,742.4 ft Step 2: 1,742.4 ft X 20 ft X 17 ft = 592,416 cu ft Step 3: Density has been given as 0.85 gal/1,000 cu ft Step 4: 592.416 cu ft X 0.85 gal = 503.5 gal/acre will apply a dilute 1,000 cu ft application to runoff. However, general pesticide applications are not applied to runoff. Using 70 percent (0.70) of the “to runoff” calculated rate reduces the dilute application just to the point of drip, or what we call “pesticide dilute.” Table 2 gives the adjustments to the “TRV calculated water rates for dilute to runoff” water application rate for various chemicals used and types of spray applications. The 503.5 gallons per acre in the example above is used to illustrate the adjustments in Table 2. Table 1. Canopy density adjustments in tree row volume (TRV) model. 0.70 gal/1,000 cu ft Trees extremely open, light visible through entire tree, less than 15 scaffold limbs per tree or young tree. 0.75 gal/1,000 cu ft Trees very open, 18 to 21 scaffolds per tree, light penetration throughout tree, healthy spurs within tree canopy. 0.80 gal/1,000 cu ft Trees well pruned, adequate light in trees for healthy spurs throughout trunk and scaffold limbs, many holes or openings in foliage where light is visible through tree. 0.85 gal/1,000 cu ft Trees moderately well pruned, reasonable spur population within canopy, tree thick enough that light is not visible through bottom b of tree. 0.90 gal/1,000 cu ft Trees pruned minimally, spurs inside canopy are weak due to limited light, very few openings where light is visible throughout the tree. 0.95 gal/1,000 cu ft Little or no pruning, spurs dead or very weak in canopy, very little light visible throughout the tree. 1.00 gal/1,000 cu ft Tree unpruned, extremely thick, no light visible anywhere through tree canopy, trees more than 20 ft high. 28 Table 2. Adjustments in tree row volume (TRV) calculated water rates per acre for various chemicals and types of spray applications. Type of spray and chemical application % of the calculated TRV dilute to runoff gallonage to be used for a dilute application Actual gallons/acre to be used in previous TRV example orchard 1Pre-petal fall dilute pesticide application (adjusted because of incomplete foliage development) 56 282 Dilute pesticide application (from petal fall on and all other applications not specifically mentioned) 70 352 ProVide and Promalin (as a fine mist) 40 to 50 201 to 252 Spur Red Delicious thinners and dormant oil applications 100 504 Thinners for other varieties 70 to 90 352 to 453 Vegetative growth inhibitor 80 to 90 403 to 453 Preharvest Ethrel plus stop-drop spray 100 to 120 504 to 605 1To use this reduced gallonage requires accurate nozzling to top of trees and good air displacement within trees (i.e., reduced tractor speed). Table 3. How to calculate concentrate application rates. Concentrate pesticide application (3X water rate)1 Dilute pesticide TRV gallonage = 352 gal/acre = 117 gal/acre Concentrate rate 3X Concentrate pesticide chemical load per acre (2X to 4X)2 Rate of pesticide Dilute pesticide per 100 gal x TRV gal/acre = 2.0 X 352 = 7.1 lbs/acre 100 gal 100 5X or greater3 Rate of pesticide Dilute pesticide per 100 gal x TRV gal/acre x 0.8 = 2.1 X 352 X 0.8 = 5.6 lbs/acre 100 gal 100 1Assume the example orchard was to be sprayed at 3X concentration. 2Rate per 100 gal dilute. Example based on 2.0 lb pesticide/100 gal. 3This adjustment for concentrate application (5X or greater) should be made if spraying conditions are good and trees are properly matched to the sprayer. Adequate spray coverage cannot be assumed with concentrate application if sprays are applied during windy conditions or to thick, oversized trees. Table 3 demonstrates how the chemical load and water volume for concentrate sprays can be easily calculated from the TRV model. The TRV model is accurate for dilute and concentrate chemical applications with conventional airblast sprayers, using water volumes as low as 150 gallons per acre. Below this gallonage, the physics of droplet size and impingement on the foliage can become a limiting factor in obtaining effective deposition on trees. Thus, if the TRV model calculates a water application rate of less than 150 gallons per acre, a 150 to 200 gallon rate should be considered a minimum in a conventional airblast sprayer, or be sure you are using a concentrate engineered sprayer (higher air speed) that will ensure adequate impingement of the spray solution on the tree surfaces at low water volume. Dwarf High-Density Orchards Dwarf high-density orchards represent a special situation for TRV applications. Most high density orchard TRV water application rates calculate out at well below the minimum desirable gallonage for good droplet impingement (below 150 gallons/acre). We have consistently found improved efficacy of pesticide application and improved time efficiency by calibrating for double the TRV. This raises the water application rate above the minimum desirable gallonage, and then you must drive every other row middle to reduce actual water volume per acre of orchard back to true TRV calculated rate. Pesticides are applied on a normal interval, alternating drive middles. The reality of sprayer calibration and nozzling for chemical applications is that until the proper chemical load is appropriately delivered and deposited on leaf and fruit surfaces, the spray you apply cannot be considered an effective pesticide application. 29 IPM Practices for Selected Pests Plum Curculio Plum curculio adults overwinter in leaf litter in and around orchards. In the spring when the daily maximum temperature exceeds 70ºF, adults emerge, mate, and lay eggs under fruit skin. This occurs near bloom, petal fall, or both, and an insecticide application at petal fall is important to minimize damage when adults are present. Adults are ¼-inch-long weevils with a curved snout; they are mottled black, gray, and brown with two bumps on each wing cover and a white marking across the back. Eggs hatch within a few days after being laid and feed in the fruit. The mature larva is ¼-inch long, white, slightly curved, and legless. Damage on apples is usually observed as feeding or oviposition scars and is cosmetic. There are two generations per year. Scouting and Control: After bloom, check twice weekly for plum curculio adults for feeding and egg-laying scars. Typically, an insecticide at petal fall and first cover (if adult emergence is protracted) is used for control. However, additional insecticides should be applied if any new damage is observed. Plum Curculio Degree-Day (DD) Model A degree-day model can help growers prepare for plum curculio emergence and determine the end of adult movement in the spring. Once buds swell, note the second date when air temperature exceeds 70ºF (biofix) and begin accumulating daily degree days (DD) (base 50ºF) using the DD table for codling moth on page 33 (base 50oF). Adults enter orchards from 50 to 400 DD after biofix. Damage occurs from 100 to 700 DD after biofix. Summer generation adults begin emerging after 1,100 DD and can cause damage until harvest. Apple Maggot Historically, the apple maggot has been a sporadic pest of apples in the southeastern U.S., but when it does occur it can cause considerable damage. The apple maggot usually completes one generation per season, but two generations are known to occur in some years. Adult flies emerge from overwintering pupae in the soil from June through September, with the major emergence period being from mid July to early August. About 7 days after emergence, flies become sexually mature and mate, after which females deposit eggs under the skin of apples by puncturing apples with their ovipositor. After a few days a small maggot hatches from the egg, and the maggot tunnels within the fruit. When mature, the maggot exits the apple, drops to the ground, and burrows into the soil, where it completes development and forms a pupa. The pupa is the overwintering stage, and it emerges as a fly the following summer. Although the majority of overwintering pupae emerge the following spring, some pupae do not emerge for 2 to 4 years. Weather conditions are important in dictating the timing and length of fly emergence. Pupae overwintering in lighter soils and in sunny areas emerge before those in heavier soils and shady areas. Sufficient soil moisture is also necessary for flies to emerge from soil-borne pupae; drought delays or prevents many flies from emerging. Abandoned orchards (or even a few nonsprayed trees) and wild hawthorn trees are potential sources of large numbers of flies and are a threat to commercial orchards located within at least 400 yards. Monitoring and Control: Monitor apple maggot adults with red sticky spheres alone or in combination with a volatile bait. Baited spheres catch two to four times as many adults as nonbaited spheres. In orchards with no history of maggot injury, a minimum of three red spheres should be placed on the outside row of an orchard closest to the suspected source of flies (e.g., abandoned orchard). Hang spheres in trees with fruit, but remove fruit adjacent to the sphere so that the sphere is clearly visible. Apply an insecticide within 7 to 10 days after catching the first fly, and repeat applications at 10- to 14-day intervals while adults are active. Codling Moth Codling moths begin to emerge and mate during April or early May, depending on location. Eggs generally begin to hatch near the first cover spray, and soon larvae tunnel into and feed inside fruit. The mature larvae are similar to Oriental fruit moth larvae, being ½-inch long and pinkish-white with legs. Unlike the OFM, codling moth larvae do not have an anal comb. Codling Moth Degree-Day Model Base a decision to spray insecticides against coding moth on pheromone trapping and the codling moth degree-day model. Use pheromone traps to determine the starting point of the model (biofix) and to gauge the intensity of populations. The degree-day model predicts percent of adult emergence and egg hatch for each of the three to four generations of codling moth that annually occur in the Southeast. To use the model, begin to accumulate degree days when male flight begins in the spring, which is referred to as biofix. The biofix date is determined with pheromone traps to detect the first sustained catch of two or more moths in the spring. Traps should be placed in orchards near the tight cluster stage of bud development, and checked one to two times per week. Traps should be hung at a density of one trap per 10 acres of orchard. Traps hung in the upper third of the canopy often catch more moths than those in the lower canopy. Once biofix is determined, degree days are calculated daily. It is only necessary to check traps once per week after biofix is determined. The table on page 33 should be used to determine the number of degree days occurring at various maximum and minimum daily temperatures. First Generation: Recommendations are provided for low and moderate to high population densities. Low-density orchards are those with less than 0.5 percent of the fruit damaged 30 the previous year and pheromone trap catches that do not exceed 10 moths per trap per week anytime before the accumulation of 200 DD after biofix. In low-density orchards, make a single insecticide application at 350 DD after biofix. In moderate- to high-density orchards, apply two insecticide applications 14 days apart, the first at 150 to 250 DD after biofix: 150 if using a product which depends primarily on ovicidal activity for control (i.e., Confirm or Intrepid), and 250 if using an insecticide that has contact activity against larvae (i.e., organophosphate or pyrethroid). Relationship between degree-day accumulations from biofix and percentages of codling moth adult emergence and egg hatch. Cumulative Degree Days % Adult Emergence % Egg Hatch Cumulative Degree Days % Adult Emergence % Egg Hatch 0 (biofix) 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1,000 1,050 1,100 1,150 1,200 1,250 1 5 15 27 40 52 63 72 80 87 91 95 97 98 99 99 100 0 1 2 5 8 13 18 26 35 0 0 0 0 0 3 9 18 30 42 54 64 73 81 87 92 95 97 98 99 100 0 1 2 3 6 1,300 1,350 1,400 1,450 1,500 1,550 1,600 1,650 1,700 1,750 1,800 1,850 1,900 1,950 2,000 2,050 2,100 2,150 2,200 2,250 2,300 2,350 2,400 2,450 2,500 2,550 43 52 60 68 77 80 85 89 92 95 97 99 0 2 4 7 10 15 20 25 31 38 45 52 59 65 10 15 21 28 36 45 63 62 69 75 81 85 89 92 95 94 99 100 3 5 8 12 16 21 27 31 Second Generation: Recommendations are provided for extremely low, low, and moderate to high population densities. Extremely low-density orchards may not require an insecticide application (i.e., pheromone trap catches never exceed three moths per trap per week between 900 to 1,900 DD after biofix for codling moth or 800 to 1,600 DD after biofix for Oriental fruit moth). Low-density orchards require one insecticide application at approximately 1,250 DD. These orchards may have no sign of damage by first generation larvae and trap catches between 3 to 7 moths per trap per week between 900 to 1,450 DD after biofix. Moderate- to high-density orchards will have fruit damage, higher pheromone trap catches requiring two insecticide applications 14 days apart starting about 1,250 DD after biofix. Third Generation: Apply an insecticide at 2,250 DD after biofix if pheromone trap catches exceed 5 moths per trap per week after 1,900 DD after biofix or if fruit damage caused by second-generation larvae is observed. Exceptions to the Model: Where codling moth populations are extremely high and where pheromone trap catches remain high between generations, additional insecticide applications may be necessary. This often occurs in orchards adjacent to an abandoned orchard or where old bins are placed near an orchard. Insecticides recommended for codling moth have sufficient residual activity so that applications made at 14-day intervals usually provide adequate protection. Oriental Fruit Moth Oriental fruit moths begin to emerge and mate before apple bloom, and eggs begin to hatch at petal fall. Variable spring temperatures cause erratic emergence and egg-laying by first-generation moths. The larvae feed on shoot tips and inside apple fruit. The mature larva is 1/2-inch long, pinkish-white, and has an anal comb and legs. The only way to distinguish between Oriental fruit moth and codling moth larvae is to use a hand lens to examine mature larvae for the presence of an anal comb. Codling moth larvae do not have an anal comb. Oriental Fruit Moth Degree-Day Model Base a decision to spray insecticides against Oriental fruit moth on pheromone trap catches and a DD model. The biofix is determined in the same manner as for the codling moth. Use pheromone traps to determine the starting point of the model and to gauge the intensity of populations. The degree-day model predicts adult emergence and egg hatch for the first three generations of the four or five generations that occur in the Southeast. However, generations overlap in the late season, which makes the degree-day model less useful later in the season. The table on page 33 uses daily maximum and minimum temperatures to determine daily DDs for Oriental fruit moth (base 45ºF). Place traps in the orchards near the green-tip stage of bud development, and check one to two times per week. Hang traps at eye-level at a density of 1 trap per 10 acres of orchard. Check traps weekly after the biofix date. First-Generation OFM: Control of the first generation is often important to prevent first-generation damage and to reduce populations of subsequent generations. First-generation egg laying is usually low on apple, and only one insecticide application between 400 and 500 DD after biofix is necessary, which usually coincides with petal fall. 31 Second-Generation OFM: If first-generation control was successful, second-generation populations are usually very low. Extremely low-density orchards may not require an insecticide application (i.e., pheromone trap catches never exceed 3 moths per trap per week between 800 to 1,600 DD after biofix). In low-density orchards (3 to 7 moths per trap per week caught between 800 and 1,500 DD), make a single insecticide application at 1,400 DD. Moderate- to high-density orchards will have fruit damage, higher pheromone trap catches, or both, and may need two insecticide applications 14 days apart starting at 1,100 DD. Third-Generation OFM: An insecticide is recommended at 2,200 DD after biofix if pheromone trap catches exceed 5 moths per trap per week at 1,900 DD after biofix and if there is fruit damage caused by the second generation. Fourth-Generation OFM: Because of overlapping generations late in the season, it is difficult to predict when egg hatch of the fourth generation begins. However, continuous egg laying can occur from August through October, and the use of pheromone traps are the best method to determine the potential for late-season damage. Apply an insecticide within 7 to 10 days of a pheromone trap threshold of 10 moths per trap per week. Maintain spray intervals on a two-week (complete) or 5- to 7-day (alternate-row-middle) schedule for as long as the threshold is exceeded. Tufted Apple Bud Moth The tufted apple bud moth (TABM) is the most important leafroller occurring in the Southeast. TABM completes two generations per year, with egg laying occurring during June (first generation) and August and September (second generation). Larvae feed on leaves and fruit, with fruit damage usually observed as surface feeding. However, second-generation larvae often feed within the calyx end of fruit. Unless an individual orchard has a history of damage by this insect, it is doubtful that special precautions need to be taken. Timing is critical to the successful management of this pest. Depending on the type of insecticide used and the intensity of the TABM population, one or two applications during each of the two generations may be necessary. Maintain a clean orchard floor, particularly in the early spring before bloom, to minimize TABM populations by removing the food source for overwintering larvae. New apple sucker growth and broadleaf weeds are important food sources in the spring. In recent years TABM populations have been reduced to very low numbers because of new insecticides used in many orchards Tufted Apple Bud Moth Degree-Day Model A TABM degree-day model similar to that of the Oriental fruit moth and codling moth has been tested and modified for populations in the Southeast. For calculating degree days from maximum and minimum daily temperatures, use the Oriental fruit moth table on page 33 (45oF). Place TABM pheromone traps at the tight cluster to pink stage of bud development at a density of 1 trap per 20 acres of orchard. Biofix is the first date on which a sustained catch occurs and may vary from 2 to 15 moths per trap over a one-week period. The cumulative number of degree days from the point of biofix is used to predict percentage of egg hatch and to time insecticide applications against the first generation. First-Generation Recommendation: When population densities are sufficiently high or if a short residual insecticide is used, two insecticide applications per generation are necessary; make the first application at about 10 percent egg hatch, which occurs between 800 and 900 DD after biofix, and the second application 14 days later. Where populations are low or if using a long residual insecticide, one application per generation should be made, and this can occur anytime between 10 and 30 percent egg hatch of the first generation, or from 800 to 1,200 DD after biofix. Second-Generation Recommendation: Depending on variety and harvest date, make one or two applications for second-generation control. For cultivars harvested by early September, a single application at 10 percent egg hatch will usually suffice; this coincides with the accumulation of about 2,600 DD after biofix (early to mid-August). Second-generation egg hatch can sometimes extend into late September, so a second application may be made in late August or early September on varieties harvested after mid- September. Mating Disruption Mating disruption programs consist of emitting relatively large amounts of sex pheromone into an orchard environment to disrupt the normal mate-location process. Mating disruption prevents mating and the subsequent laying of fertile eggs, which effectively reduces populations below economically damaging levels. It is effective only in blocks of 5 acres or more. In apples, mating disruption is registered for control of both codling moth and Oriental fruit moth. Oriental fruit moth is much easier to control with mating disruption compared with codling moth; against moderate to high codling moth populations, both mating disruption and insecticides should be used. Time insecticide applications to coincide with egg hatch of the target pest. High population densities of Oriental fruit moth have been successfully controlled with pheromones alone. Mating disruption will not control infestations resulting from immigrating fertilized female moths; hence, mating disruption alone is not recommended in blocks located adjacent to a likely source of immigrating moths (i.e., abandoned orchards or bin storage areas). Pheromone Dispensers: A number of companies market pheromone dispensers for mating disruption, including hand-applied dispensers that emit pheromones for a relatively long period and sprayable products that last for shorter periods and need to be reapplied. Isomate-CTT is a common codling moth pheromone dispenser that lasts for the entire growing season. Use approximately 150 to 200 dispensers per acre, with the lower rates recommended in orchards where mating disruption has been previously used or with very low population densities. Isomate-M100 (100 dispensers per acre) and Isomate Rosso (160 dispensers per acre) are Oriental fruit moth pheromone dispensers that last about 85 and 140 days, respectively. Under low population densities, it is possible to reduce OFM dispenser rates to approximately 75 percent of the full rate. Suterra Inc. makes a sprayable 32 pheromone product for the Oriental fruit moth, with residual activity of 4 to 5 weeks; hence, these products need to be reapplied at 4- to 5-week intervals. Timing of Applications: For the codling moth, place pheromone dispensers in the orchard before adults begin to fly in the spring. First emergence of adults usually begins during late bloom or petal fall of Delicious cultivars. Hence, dispensers should be hung by petal fall. For codling moth, best results are obtained when dispensers are hung in the upper third of the canopy. The Oriental fruit moth begins to emerge near green tip of Delicious cultivars, so for season-long control dispensers should be in the orchard by this time. However, if an insecticide effective against Oriental fruit moth is used at petal fall, it will control the first generation. It is possible to delay placement of Isomate-M100 until just before emergence of second- or third-generation adults (950 and 1850 DD after biofix, respectively). This delayed placement should prevent the need for a second application of Isomate M100 dispensers, which may otherwise be necessary on later maturing cultivars. If using sprayable pheromones for mating disruption, make the initial application when hand-applied dispensers are applied. Monitoring Insects: Checking fruit for larval damage is critical to determining the effectiveness of mating disruption and the need for rescue sprays. Monitoring adult populations of codling moth and Oriental fruit moth with pheromone traps is strongly recommended to provide baseline information on population density, to monitor the effectiveness of mating disruption, and to improve the timing of mating disruption and insecticide treatments. Good monitoring is an important part of achieving successful results. Effective pheromone mating disruption treatments will shut down trap catches of male moths. However, pheromone trap monitoring should not be used as the sole method of measuring efficacy. Also remember that mating disruption is species specific, so monitoring of other insect pests is also important. European Red Mite Management Several beneficial arthropods can help keep European red mite (ERM) populations below damaging levels. The most common in the Southeast are the phytoseiid mite (Amblyseius fallacis) and the a complex of generalist predators (e.g., lady beetles and lacewings). However, recent research in North Carolina suggests that neither of these predators overwinters to any significant degree within orchards, so they must be reestablished in orchards in the spring. Hence, practices that delay the buildup of ERM and enable predators to increase before mites become a problem will favor biological control. The two most effective practices are applying a delayed dormant oil spray and avoiding insecticides toxic to these predators. Monitoring Mite Populations: Use a regular monitoring program to follow the buildup of mite populations and to determine if and when supplemental applications of a miticide are necessary to avoid economic damage. Monitor each contiguous block of apples weekly beginning when adult mites first appear (which may vary from mid May to early July). Within each block, examine 5 leaves from each of 10 trees with a visor lens or hand lens. Rather than counting the total number of mites on each leaf, record the number of leaves infested with one or more mites, and estimate the mite density on a per-leaf basis from the table below. Determining the Need for Miticides: When mite populations reach a density of 5 to 10 mites per leaf (80 to 90 percent infested leaves) decide whether to use biological control or a miticide to prevent mites from increasing to higher densities. For biological control with Stethorus punctum to occur, the ratio should be 2.5 S. punctum to 1 ERM. S. punctum should be sampled by counting the number of adults and larvae observed during a timed 3- minute search around the periphery of mite-infested trees. S. punctum larvae must almost always be present if this predator is to control mites. Count the actual number of A. fallacis on sample leaves with a visor lens. If the ratio of A. fallacis to ERM is between 1 to 5 and 1 to 15, biological control is possible. If neither predator is present at sufficient levels for biological control to occur, and mite populations are between 5 to 10 mites per leaf, apply a miticide. In areas where Alternaria blotch is a problem on Delicious apples, biological control is usually not an option. In the presence of Alternaria blotch, mite populations must be maintained a very low levels to avoid high levels of Alternaria and premature defoliation. If preventive control measures are not used, a modified threshold level of 1-2 mites per leaf should dictate the need for miticides. Relationship between European red mite densities per leaf and percentage of mite-infested leaves. % Mite-Infested Leaves (>1 mite/leaf) Expected No. Mites per Leaf % Mite-Infested Leaves (>1 mite/leaf) Expected No. Mites per Leaf 40 45 50 55 60 65 0.7 0.9 1.1 1.3 1.6 2.0 70 75 80 85 90 95 2.6 3.4 4.7 6.8 11.4 26.4 33 Codling moth degree days (50oF lower base, 88oF upper base) at various daily maximum and minimum temperatures. Max 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 Min 20 0 1 1 2 2 3 3 4 5 5 6 7 8 9 9 10 11 12 13 14 15 15 22 0 1 1 2 2 3 3 4 6 6 6 7 8 9 10 10 11 12 13 14 15 15 24 0 1 1 2 2 3 4 4 6 6 7 7 8 9 10 11 11 12 13 14 15 16 26 0 1 1 2 2 3 4 4 6 6 7 7 8 9 10 11 12 12 13 14 15 16 28 0 1 1 2 2 3 4 4 6 6 7 8 8 9 10 11 12 13 14 15 15 16 30 0 1 1 2 2 3 4 5 6 6 7 8 9 10 10 11 12 13 14 15 16 16 32 0 1 1 2 3 3 4 5 6 6 7 8 9 10 11 11 12 13 14 15 16 17 34 0 1 1 2 3 3 4 5 6 7 7 8 9 10 11 12 13 14 14 15 16 17 36 0 1 1 2 3 4 4 5 6 7 8 8 9 10 11 12 13 14 15 16 17 17 38 0 1 1 2 3 4 4 5 6 7 8 9 10 11 11 12 13 14 15 16 17 18 40 0 1 2 2 3 4 5 6 6 7 8 9 10 11 12 13 14 15 16 17 17 18 42 0 1 2 2 3 4 5 6 7 7 8 9 10 11 12 13 14 15 16 17 18 19 44 0 1 2 3 3 4 5 6 7 8 9 10 11 12 13 14 15 15 16 17 18 19 46 0 1 2 3 4 5 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 48 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 20 50 1 2 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 52 2 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 54 - 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 56 - 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 58 - - 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 60 - - - 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 62 - - - - 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 64 - - - - - 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 66 - - - - - - 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 68 - - - - - - - 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 70 - - - - - - - - 18 19 20 21 22 23 24 25 26 27 28 29 30 31 72 - - - - - - - - - 20 21 22 23 24 25 26 27 28 29 30 31 32 74 - - - - - - - - - - 22 23 24 25 26 27 28 29 30 31 32 33 76 - - - - - - - - - - - 24 25 26 27 28 29 30 31 32 33 34 80 - - - - - - - - - - - - 26 27 28 29 30 31 32 33 34 35 Oriental fruit moth degree days (45oF lower base, 91oF upper base) at various daily maximum and minimum temperatures. Max 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 Min 20 1 1 2 2 3 4 4 5 6 7 8 9 9 10 12 12 13 14 15 16 17 17 18 19 22 1 1 2 2 3 4 4 6 7 7 8 9 10 11 12 12 13 14 15 16 17 18 18 19 24 1 2 2 2 4 4 5 6 7 7 8 10 10 11 12 12 14 15 15 16 18 18 19 20 26 1 2 2 3 4 5 5 6 7 7 8 10 10 11 12 13 14 15 16 16 18 18 19 20 28 1 2 3 3 4 5 5 6 7 8 9 10 10 11 13 13 14 15 16 17 18 19 20 20 30 1 2 3 3 4 5 5 6 7 8 9 10 10 12 13 13 15 16 16 17 19 19 20 21 32 1 2 3 3 4 5 6 6 8 8 9 10 11 12 13 14 15 16 17 18 19 19 20 21 34 1 2 3 3 4 6 6 7 8 8 10 11 11 12 14 14 15 17 17 18 19 20 21 21 36 1 2 3 3 5 6 6 7 8 9 10 11 11 13 14 14 16 17 18 19 19 20 21 22 38 1 2 3 4 5 6 6 7 9 9 10 11 12 13 14 15 16 17 18 19 20 21 21 22 40 1 2 3 4 5 6 6 8 9 9 10 11 12 13 15 15 16 18 18 19 20 21 22 23 42 1 3 4 4 6 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 44 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 46 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 48 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 50 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 52 - 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 54 - - 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 56 - - - 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 58 - - - - 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 60 - - - - - 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 62 - - - - - - 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 64 - - - - - - - 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 66 - - - - - - - - 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 35 68 - - - - - - - - - 23 24 25 26 27 28 29 30 31 32 33 34 35 36 36 70 - - - - - - - - - - 25 26 27 28 29 30 31 32 33 34 35 36 37 37 72 - - - - - - - - - - - 27 28 29 30 31 32 33 34 35 36 37 38 38 74 - - - - - - - - - - - - 29 30 31 32 33 34 35 36 37 38 39 39 78 - - - - - - - - - - - - - 31 32 33 34 35 36 37 38 39 40 40 80 - - - - - - - - - - - - - - 33 34 35 36 37 38 39 40 41 41 34 Pesticide Resistance Management General Considerations Pesticide resistance is a shift in the genetics of a pest population that allows individuals within a previously susceptible population to survive. Resistant pest populations have inherited traits that reduce their susceptibility to individual pesticides or groups of pesticides. Resistance develops in all agricultural pest groups–insects, mites, fungi, bacteria, nematodes, and weeds. Pesticide-resistant individuals are initially quite rare in pest populations. However, when a new pesticide is first used, a very low number of individual pests never previously exposed to the novel chemistry can be expected to be resistant. The frequency of resistant genes to novel chemistries varies tremendously, but history makes it clear that resistant individuals should be expected to be present in all pest groups. By the nature of the process, resistance most often develops to pesticides that are initially very effective and frequently used. Pesticide resistance management is an effort to slow or prevent the development of resistance. It relies on pest management and pesticide-use strategies to prolong the effective life of pesticides. Resistance management is difficult, especially in high-value crops like fruit, where high quality standards and limited numbers of registered pesticides make the task more challenging. Managing resistance requires an understanding of the factors that influence its development. Selection is the process of pesticide-induced selection for resistance. With regular pesticide use, those rare individuals that are naturally resistant survive and reproduce more successfully than their susceptible peers. Resistance frequency refers to the proportion of a pest population that is resistant. Cross resistance refers to a type of resistance in which a pest population develops resistance to more than one pesticide within a chemical family (e.g., organophosphate insecticides, EBDC fungicides, etc.). Multiple resistance involves multiple, independent resistance mechanisms, which often lead to resistance to chemicals from different families (i.e., organophosphate and carbamate insecticides, dodine and DMI fungicides). Resistance stability is a key factor in managing resistance. Stability is an estimate of how well resistance persists in a pest population once the pesticide is no longer used. The rate of reversion to a susceptible state varies enormously. But when pesticide use ceases, selective pressure for resistance is removed, and over time resistance will often be reduced. Resistance stability estimates may allow limited use of resistance-prone compounds. It is important to emphasize that control failures do not confirm resistance. Other factors (poor timing, sprayer calibration or coverage, wash-off, high pH in spray tank water, inappropriate materials, etc.) should be eliminated as causes for control failures before resistance is seriously considered. Factors influencing the development of resistance can be grouped into biological and management categories. Biological factors include pest reproductive rate, mobility of the pest species into and out of untreated areas, and genetic factors such as number of resistance mechanisms, resistance frequency and intensity, and resistance stability. Management factors that influence resistance development include how materials are applied, how often they are used, how long they persist in the field, treatment thresholds, and strategies for using available pesticides. Resistance management efforts study specific pest-pesticide interactions and focus on practical strategies that growers can implement. Pest management is practical and works in concert with pesticide-use strategies to lessen resistance selection by facilitating prudent, as-needed pesticide use. Pesticide-use strategies work best when implemented as a new pesticide comes into commerce. Pesticide manufacturers, IPM scientists, and growers have come to recognize that using resistance management from the beginning works best. Collecting baseline susceptibilities, defining probable resistance problems beforehand, and proposing pesticide-use strategies to forestall resistance development are the province of manufacturers and IPM scientists. Biologically and economically sound resistance management plans offered pre-sale give growers the best hope for managing resistance. Pesticide-use strategies are often grouped as follows: (1) management by moderation, (2) rotation and mixtures, and (3) saturation. Moderation means limiting the use of a pesticide. Moderation is employed in concert with IPM practices, such as using treatment thresholds, spraying only specific pest generations or growth stages, maintaining unsprayed wild host reservoirs to act as refuges for genetically susceptible individuals, using pesticides with shorter residual or lower toxicity to important beneficial populations, etc. Moderation should be used to the fullest extent that will provide commercially acceptable control. Rotation, and in some cases mixtures, are the bulwarks of pesticide-use strategies since an individual pest is less likely to be resistant to two or more differing classes of toxins. In theory, most individual pests resistant to one pesticide will be killed when exposed to a different class of toxin. Rotations depend on having effective, labeled materials with different modes of action. Material cost is a key practical consideration that favors rotation. Mixtures of fungicides have been used successfully to combat disease resistance, although cost lessens the attractiveness of this approach. Mixtures of insecticides and miticides have typically performed poorly. Rotation is seen as the desired approach for insecticides, miticides, and some fungicides. Saturation, the use of higher pesticide rates to control resistant individuals, is the least attractive resistance management approach, although it has been used to manage resistance to DMI fungicides. Saturation is generally a last resort, when there are no other effective, labeled alternatives. In this scenario, higher rates will often provide control for a time, although at greater cost. Synergists, chemicals that increase the toxicity of pesticides, have sometimes been effective in boosting the efficacy of resistance-prone pesticides. As with simple rate increases, saturation with synergists typically provides only short-term benefits. 35 Insecticide Resistance Management Strategies In the southeastern United States, the tufted apple bud moth, codling moth, rosy apple aphid, and European red mite have developed resistance to one or more pesticides. Although codling moth and mite resistance are not widespread in the Southeast, problems in other parts of the U.S. indicate the importance of employing sound pesticide use patterns to prevent resistance development in this region. Tufted Apple Bud Moth The tufted apple bud moth has developed resistance to organophosphate insecticides, most notably Guthion and Imidan. However, Intrepid, SpinTor, Avaunt, Rimon, and Danitol are effective alternatives. Along with Bacillus thuringiensis products, these products provide growers with a diversity of options with different modes of action to manage TABM. The recommended strategy is this: Do not use the same insecticide (or insecticides with the same mode of action) against successive generations. For example, if Intrepid is used against the first generation in year 1, then Avaunt, Rimon or SpinTor should be used against the second generation. Against the first generation in year 2, do not use the same insecticide used to control the second generation in year 1. When selecting an insecticide, one should consider other insects that also may need to be controlled. Rosy Apple Aphid The rosy apple aphid has developed widespread resistance to Lorsban, and control failures with Thiodan, Asana, Ambush, Diazinon, and Dimethoate have become more common in recent years. Among the neonicotinoid insecticides, suspected failure with Actara has been observed. However, all the neonicotinoids (i.e., Actara, Assail, Calypso, Clutch, and Provado) have a similar mode of action and should be considered the same material for rotation purposes. The two best times to control rosy apple aphid on apple are 1) tight cluster to pink and 2) petal fall. Do not apply any insecticide more than once during this time frame, and if possible do not use the insecticide used for rosy apple aphid control more than once during the period when the aphids may occur in apple orchards (through the third or fourth cover spray). European Red Mite Avoiding unnecessary miticide applications is the most effective strategy for minimizing the potential for resistance development. A delayed dormant oil application is highly recommended to suppress overwintering populations of European red mite and to improve the potential for biological control to maintain mite populations below damaging levels. On Delicious cultivars, which are susceptible to alternaria blotch and where preventive control or low threshold levels are recommended for control of European red mite, there is a high potential for the development of resistant populations. To reduce this potential, in addition to a delayed dormant oil application, only one of the following options should be used in a given year, and the same option should not be used in two consecutive years. Preventive Strategies Curative Strategies • Agri-Mek + oil at petal fall • Apollo or Savey at first or second cover • Zeal at first or second cover • Envidor at first or second cover • Acramite at 2 mites per leaf • Nexter at 2 mites per leaf Resistance Management Strategies for Plant Pathogens Resistance of plant pathogens to pesticides has become widespread over the past 25 years as site-specific (systemic) chemicals have been developed and used on many crops and against many pathogens. The broad spectrum protectants (such as captan and mancozeb) that were used previously had multiple sites of activity in the target pathogens, greatly reducing the likelihood of resistance development. Resistance has become a problem in the U.S. in only three pathogens that affect apples during the growing season: Venturia inaequalis, cause of apple scab; Erwinia amylovora, cause of fire blight; and Pseudomonas syringae pv. papulans, cause of blister spot. Resistance of V. inaequalis to dodine (Syllit, initially sold as Cyprex) was first reported in New York in 1969. It has subsequently been reported in several states in the Northeast and Midwest but has not been found in orchards in the Southeast. Resistance of V. inaequalis to the benzimidazole fungicides [benomyl (Benlate) and thiophanate methyl (Topsin M)] was reported shortly after their introduction in 1971 and became widespread in the eastern U.S., including the Southeast, in the mid-1970s. As a consequence they are no longer recommended for apple scab control in the Southeast. The ergosterol biosynthesis inhibiting fungicides [fenarimol (Rubigan), myclobutanil (Nova), triflumazole (Procure)] were first introduced in the late 1980s, and reduced sensitivity of V. inaequalis has been reported or suspected in a number of orchards in the Northeast and Midwest but is not widespread. Resistance of the fire blight bacterium, E. amylovora, to streptomycin (Agri-mycin 17, Streptrol) is widespread in several states but has not been reported in the Southeast. Resistance of P. syringae pv. papulans has been confirmed in an orchard in Tennessee. To avoid resistance development, minimize the use of fungicides and bactericides in which resistance is likely to develop. Additionally, combine site-specific fungicides with protectant fungicides that have broad spectrum activity. Limit dodine applications to two to three per year. In areas where dodine resistance first became a problem, it was often used 10 to 12 times throughout the growing season. Similarly, limit streptomycin use for fire blight control to two to four times a year. Make applications only during times favorable for infection. These periods are characterized by open blossoms, dew or rainfall 36 greater than 0.01 inch, an average daily temperature of 60º F or greater, and the accumulation of at least 198 degree-hours greater than 65º F since the first blossoms opened. Use the ergosterol biosynthesis inhibiting fungicides only in combination with broad spectrum protectants, such as captan or EBDC fungicides. Avoid post symptom applications of site-specific fungicides, such as dodine and the DMI fungicides, because this sets up an ideal situation for selection of resistant strains. Good orchard sanitation practices to maintain pathogen populations at low levels is also an important component of a resistance management program. Managing Weeds and Preventing the Development of Herbicide Resistance Although weed resistance to herbicides is not discussed as often as resistance in insects and pathogens, cases of weed resistance to herbicides do exist. For example, pigweed and goosegrass are resistant to dinitroanaline herbicides (Prowl and Surflan), and Johnsongrass is resistant to carboxylase herbicides (Fusilade DX). Resistance may not be detected for several years because these resistant weeds produce seed, and then subsequent generations must establish. Two factors that contribute to the development of herbicide-resistant weeds are applying herbicides multiple times during the year and using herbicides that have the same mechanism of control for several consecutive growing seasons. Because apples are a perennial crop and have limited herbicide options, techniques like crop rotation and mechanical cultivation to prevent resistance in annual crops are not feasible. However, some of the following strategies can help prevent resistance from developing: 1. Use herbicides ONLY when necessary. 2. Rotate herbicides with different modes of action. For example, do not use simazine (Princep, Simazine) continuously. Consider other preemergence broadleaf herbicides. Also avoid making more than two applications of the same herbicide in the same year. 3. Scout orchards regularly to identify weeds. Respond quickly to changes in weed population by controlling weeds before they spread through the entire orchard. 4. Use nonselective postemergence herbicides in your weed management program. Effect of pH on Pesticide Activity Although the pH of spray water does not directly affect resistance development, it can affect the activity of some pesticides. In most instances the label warns of this effect. These include dimethoate, phosmet, malathion, azinphosmethyl, formetanate, ethephon, NAA, and possibly others. When these materials, except NAA, are exposed to a pH above 7.5, they undergo hydrolysis and break down to products that are either less effective or not effective. Excessively acidic conditions may limit uptake of NAA and, therefore, its effectiveness. The actual rate of breakdown depends on solubility and temperature and the total quantity broken down during a given period. For example, captan is hydrolyzed very quickly at alkaline pHs, but because it is very insoluble, the impact of pH is negligible unless captan is allowed to stand around for a week or more. This is also true for chlorothalonil. Hydrolysis increases with increased temperature. If the time in the spray tank is limited by applying pesticides immediately, then the quantitative amount broken down is limited. Additives to the spray tank can also be a factor. Calcium chloride, especially when concentrated in the tank and applied in a low volume spray, can increase the pH. The greater the concentration, the greater the alkalinity. The manufacturing process for calcium chloride leaves residues of free lime (calcium hydroxide). The greater the purity of the calcium chloride, the lower the content of calcium hydroxide and the lower the effect on pH. The water source can be a factor. Although most wells, streams, and rivers in the southeastern growing region are mildly acidic (6.7 plus or minus 0.2) there are exceptions; therefore, check pH a few times before regular use. Ponds are more likely to be alkaline, especially those high in algae and other organisms. These ponds undergo diurnal pH changes as result of dissolved carbon dioxide. Levels greater than 10 have been observed. Alkalinity contributed by CO2 is weakly buffered and readily changed by acidifying agents. Although not pH-related, some pesticides can be affected by other contaminants in the water. For example, fenbuconazole, not labeled on apples, is greatly reduced in effectiveness by suspended particulates. Still other compounds like 2,4-D and azoxystrobilurin can be very difficult to wash out of the tank and can have a deleterious effect on apples at very low concentrations. 37 Orchard Floor Management The best strategy for managing the orchard floor is to use a noncompetitive grass alley with a vegetation-free strip in the tree row. The vegetation-free strip can be established and maintained with herbicides as described in this section. The permanent grass sod between the tree rows will minimize soil erosion, increase soil aeration and permeability, and support equipment movement through the orchard during wet weather. The vegetation-free strip eliminates competition for water and nutrients, minimizes tree damage or loss from voles during the dormant season, and provides some radiant heat from the soil surface should a spring frost or freeze occur. Herbicides are directed at the soil and weeds underneath the tree. The vegetation-free strip method is superior to all other orchard floor management options. Vegetation under the tree competes for nutrients and water, resulting in reduced growth, yield, and size of fruit. Another option is the use of organic mulches in the tree row. Examples of mulching materials include straw, wood chips, and grass residue from mowing. These mulches will suppress weed emergence, but weed removal by some means will still be necessary. Mulches can improve the water-holding capacity of some soils. However, there are several concerns regarding the use of organic mulches. The most significant problem is that mulches create an ideal habitat for voles. Also, additional nitrogen may be needed to support the microorganisms that drive decomposition of organic mulches. In poorly drained or water-logged soils, organic mulches increase the likelihood of phytophthora root rot. Mulches can be expensive and difficult to obtain. Synthetic mulches made from polyethylene, polypropylene, or polyester can be placed in the tree row around the base of the trunk or as a narrow strip down the row. Some newer synthetics allow water and air to pass through the mulch. Herbicide Considerations To ensure proper herbicide use, always read the manufacturer*s label before application. All statements on the manufacturer’s label take precedence over any recommendations in this publication. It is important that herbicide application equipment be properly calibrated to ensure that herbicides are applied at the correct rate. For questions about calibrating your sprayer, contact your county’s Cooperative Extension agent. Remember that herbicides are applied as a directed spray along each side of the tree row. Flat fan nozzles are most widely used for applying herbicides. They provide excellent spray coverage of weeds and come in several sizes with capabilities to apply a range of spray volumes. Some manufacturers make flat fan nozzles that minimize spray drift, allowing low pressure spraying. Investing in such spray nozzles decreases the likelihood of off-target herbicide movement. It is advisable to apply white latex paint to the bottom 2 to 3 feet of the tree trunk of newly planted trees before applying herbicides. Painting the tree trunks reduces the potential for winter as well as herbicide injury, especially from postemergence herbicides. Dip a car wash mitt (wear rubber gloves underneath the mitt) in paint and rub up and down the tree trunk until it is completely painted. Several herbicides are registered for use in apple orchards. Some are preemergence herbicides that control weeds that have not emerged, and others are postemergence herbicides that control emerged weeds. Preemergence herbicides control germinating weed seeds but usually do not give acceptable control of emerged weeds. Rainfall is needed to properly activate preemergence herbicides. Rainfall within 7 to 14 days after application activates most herbicides; however, best control occurs when water (rain or irrigation) is added within a few days of application. The desired amount of time for rainfall after application varies by herbicide. Refer to the manufacturer’s label for specific information. Postemergence herbicides control emerged weeds and are most effective when applied to actively growing weeds. Weeds under stress from drought or mowing may not be adequately controlled by postemergence herbicides. If weeds are stressed from drought, delay herbicide application until after adequate rainfall when weeds are no longer wilted. If weeds have been mowed, wait several days to allow regrowth before applying herbicides. Symptoms of herbicide activity may not be noticeable for up to 14 days after application of glyphosate, sethoxydim, clethodim, or fluazifop (Roundup, Poast, Select, or Fusilade DX, respectively). Effects of glufosinate, paraquat, and 2,4-D (Rely, Gramoxone Max, and Orchard Master, respectively) are noticeable in 1 to 3 days. Some postemergence herbicides require the addition of a surfactant or crop oil to improve herbicide activity. Remember, surfactants and crop oil differ from one another and may not be interchangeable. Herbicide Application Timing The goal of an effective weed management program is to eliminate weed competition the first 6 to 8 weeks after bud swell and keep the area under the trees weed-free through harvest. Timing of preemergence (PRE) herbicide application is important in accomplishing this goal. It has been typical to make a single PRE herbicide application in the spring followed by postemergence (POST) herbicide applications in the summer as needed. However, it can be difficult to spray underneath limbs loaded with fruit in mid and late summer. With appropriate PRE herbicide timing, POST herbicide applications in mid and late summer can be avoided. Listed below are several PRE herbicide timing options. 1. Fall/Spring Split. One approach is to apply a PRE herbicide with a nonselective burn-down herbicide (glyphosate or paraquat) in the fall after harvest (November). The fall application will generally provide PRE control into the early summer. When fall PRE treatment breaks and emerging weeds get 2 to 3 inches tall, another PRE herbicide application with a burndown herbicide should be applied. Fall herbicide application may be helpful in managing voles. In areas where erosion is a concern this option may not be acceptable. 2. Delayed Preemergence. This approach requires a burndown herbicide application in March. The burndown herbicide eliminates winter annual weeds until summer annual weeds emerge in early to mid May. Once summer annual weeds get 2 to 3 inches, apply a burndown with a PRE herbicide. 38 Postemergence herbicides may be necessary to control escaped weeds or certain problem weeds like Bermudagrass, Johnsongrass, and mugwort. It is important to scout orchards regularly to determine weed species present. Scouting allows growers to recognize the need to control escaped weeds with a timely herbicide application and for early identification of difficult-to-control weeds. Early identification of problem weeds can prevent them from becoming established in the orchard. If problem weeds are noticed for the first time in an orchard, they need to be removed before they produce seed. This can be done by hand or with a spot treatment with a nonselective postemergence herbicide like glyphosate, paraquat, or glufosinate (Roundup WeatherMax, Gramoxone Max, or Rely, respectively). Scouting also gives growers an opportunity to recognize poorly controlled weeds so their weed management program can be adjusted. Another aspect growers should consider is the potential for infestations of weeds from around the border of the orchard. Weeds in these areas produce seeds that will find their way into the orchard. Chemical Mowing Some herbicides can be used at sublethal doses to suppress orchard floor vegetation. Timing and rate will vary with the vegetation present. Generally, tall fescue can be used as the guiding species, because it is a major component in most orchards. Optimum timing for suppression is when tall fescue has 3 to 6 inches of new growth in the spring. The following herbicides and rates are suggested: Roundup WeatherMax at 4 fluid ounces, generic glysophate products at 5 to 6 fluid ounces, and Poast 1.5E at 1 to 1.25 pints per acre. Chemical suppression of grasses should be done only to healthy, well-established sod. Refer to product labels for details. Weed Management in Newly Planted Trees Eliminating weed competition is an important part of minimizing posttransplant stress to newly planted trees. Research has shown that weed competition can reduce tree growth and development by 50 percent. Newly planted orchards are not nearly as competitive with weeds as older, established orchards. Young trees do not have well-developed limbs to shade the soil surface in late summer, which minimizes the competitiveness of late summer weeds. In general, preemergence herbicides registered for use after transplanting provide effective preemergence control of annual grasses and small-seeded broadleaf weeds. Painting the lower 18 inches of the tree trunk with a white latex paint is highly recommended. The paint provides a barrier to herbicides, protecting tender, green bark from serous injury. Apple Pollination, Honey Bees, and Pesticides Most apple varieties are self-incompatible and require cross-pollination with a suitable pollinizer variety to obtain good fruit set. Honey bees and other native bees are the primary pollinators for apples. All bees are susceptible to insecticides and need to be protected during bloom and at other times. Most insecticide labels include a warning: “This product is highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops if bees are visiting the treatment area.” Any apiary within 2 ½ miles of the orchard is at risk from insecticide applications. Bees are highly attracted to flowers in the ground cover. Before applying insecticides, reduce dandelion, clover, and other ground cover flowers by mowing or herbicide. The following recommendations will help to minimize bee kills: ! Read and obey warning statements on pesticide labels regarding honey bees. ! Select the safest available formulation. Emulsifiable concentrate (EC) formulations usually have shorter residual toxicity than wettable powder (WP) formulations. ! Insecticides applied during unusually low temperatures will remain toxic to bees for a much longer time compared to normally warm weather. ! Avoid applying insecticides to blooming cover crops, and avoid insecticide drift to nearby plants in bloom. ! If an insecticide hazardous to bees must be used, apply it in the early evening to minimize hazard to bees. Always check to make sure bees are not foraging when pesticides are applied. ! Never apply a pesticide directly over a beehive. Notify neighboring beekeepers when applying pesticides toxic to bees. ! Dispose of all unused pesticides safely so that pesticides do not end up in watering sources used by bees. 39 Soil and Plant Analysis Guidelines for Southeastern Apple Production Routine nutrient analysis of soil and plant leaf tissue should be an integral part of any orchard management plan. Soils used for apple production in the Southeast vary greatly, especially in the mountains. Other factors, such as weather and crop history, can affect the trees’ nutrient status. The only way to be sure your trees are being fertilized efficiently and properly is by using soil and plant analysis. Proper use of these tools will help ensure sustained yields while preventing unneeded fertilizer application. Ideally, both soil and plant sampling should be done every other year. On sites that have a history of nutritional problems, such as bitter pit, sampling every year may be needed. A soil analysis estimates the ability of the soil to supply a particular nutrient. Plant tissue analysis measures the current nutrient status of the tree. Potential nutritional problems can often be detected before visual deficiency symptoms appear. By using both soil and plant analysis together, a fertility program can be custom designed for your orchard. The general idea is to give each block of trees what is needed for growth and apple production, but not to apply nutrients that can be supplied by the soil in adequate amounts. Sampling for Soil Analysis A soil analysis report is only as good as the sample it represents. For soil analysis to be meaningful, the sample must be representative of the soils in the orchard. Due to soil variability, each sample should represent no more than a 5-acre block of similar terrain and soil type. Trees in the block should be of the same age, rootstock, and variety. A good sample consists of up to 20 sub-samples (cores). These should be throughly mixed in a clean bucket before filling the soil sample box. Samples should be divided into two depths: 0 to 6 inches and 6 to 12 inches. This is easiest when using a soil sampling tube. Sampling for Plant Analysis Plant sampling needs to be carried out in a manner similar to soil sampling. For best results, plant sampling areas should be the same as selected for soil sampling. All trees should be the same age, variety, and rootstock. To make full use of published critical nutrient levels, and thus obtain the best information, routine plant samples should be taken mid June to mid July, with earlier sampling at lower elevations. Sample mid-shoot of this season’s growth from the upper third of the tree. Collect a total of 40 leaves taken from at least ten trees selected randomly from the sample area. Using Soil and Plant Analysis as an Aid in Troubleshooting Soil and plant analysis can be invaluable in properly identifying and correcting nutrient deficiencies. In this case, samples are collected over a smaller area that represents the problem. If possible, it is advisable to collect samples from “good” areas adjacent to the problem areas. Both soil and plant samples need to be collected. Interpretation of Soil and Tissue Analysis Soil and plant analysis laboratories differ in analytical procedures and report format. Southeastern laboratories, both private and public, use at least two different soil-extracting solutions. A single soil sample processed by these two methods could yield very different results, especially for phosphorus. Also, different laboratories report the results in different units – some use an index system while others report parts per million or pounds per acre. A given laboratory takes these factors into account when giving fertility recommendations. In other words, their recommendations are calibrated to their methods. Thus recommendations from different labs’ soil analyses should be similar. However, the differences in reporting units make it difficult to compare results from different laboratories. To track the progress of a fertility program over the life of the trees, it is best to use either one laboratory or pick laboratories with the same methods and reporting units. Even though tissue analysis methods are more uniform, reporting units still differ between laboratories, making it difficult to track trends over time. Special Considerations for Calcium and Boron Calcium and boron deficiency can result in fruit being culled due to bitter pit (calcium deficiency) or cork spot (boron deficiency). In some years, the percentage of cull fruit exhibiting bitter pit or cork spot can be quite high. These nutrients can be difficult to supply in needed quantities, especially in older trees and large-f
Object Description
Description
Title | Integrated orchard management guide for commercial apples in the Southeast |
Date | 2006 |
Description | 2006 |
Digital Characteristics-A | 791 KB; 79 p. |
Digital Format |
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Full Text | 2006 Integrated Orchard Management Guide for Commercial Apples in the Southeast Alabama Cooperative Extension System Auburn University University of Arkansas Division of Agriculture Cooperative Extension Service University of Arkansas Clemson Cooperative Extension Service Clemson University University of Georgia Cooperative Extension Service University of Georgia North Carolina Cooperative Extension Service North Carolina State University University of Tennessee Agricultural Extension Service University of Tennessee Poison Control Centers and Emergency Facilities PESTICIDE POISONING – Symptoms of pesticide poisoning may include headache, blurred vision, weakness, nausea, cramps, diarrhea, and chest discomfort. If any of these symptoms occur during or after mixing or applying pesticides or if an unintended unprotected exposure such as a spill occurs, stop work at once and take appropriate action. If pesticide is spilled on the skin, immediately wash the area thoroughly with large amounts of soap and water. If pesticide is in the eye, flush the eye for 15 minutes in running water. If pesticide is inhaled, move to open, clean air. If pesticide is ingested, rinse out the mouth. Follow all label first aid directions. Give CPR if indicated. Get help. Contact your physician or poison control center (listed below or on WPS safety poster). Transport the victim to the closest medical care facility. Take the pesticide container or the label with you, or have others search for the label and get it to the facility. Most pesticide poisonings are due to overexposure to organophosphate and carbamate insecticides. Investigation indicates these are the result of misuse, disregard for safety precautions, and lack of proper hygiene during mixing and application. Ninety percent of occupational exposure is through the hands. Use neoprene or butyl rubber gloves. Rubber boots prevent acute exposure from spills and chronic exposure from accumulation of residues in materials of boots and shoes. STATE-DESIGNATED POISON CENTERS ALABAMA Regional Poison Control Center 800-292-6678 The Children’s Hospital of Alabama 205-933-4050 (business) 1600 7th Ave South Birmingham, AL 35233-1711 ARKANSAS Poison and Drug Information Center 800-482-8948 University of Arkansas for Medical Sciences 4301 West Markham-Slot 522 Little Rock, AR 72205 GEORGIA Georgia Regional Poison Control Center 800-282-5846 Grady Memorial Hospital 404-525-3323 (for the deaf) 80 Butler Street South East 404-616-9000 (business) Atlanta, GA 30335-3801 NORTH CAROLINA Carolinas Poison Center 800-848-6946 (in NC) Carolinas Medical Center 800-222-1222 (nationally) 1000 Blythe Blvd 704-355-4000 (business) Charlotte, NC 28232-2861 SOUTH CAROLINA Palmetto Regional Poison Control Center 800-922-1117 College of Pharmacy 803-777-1117 (local) University of South Carolina 803-777-7909 (business) Columbia, SC 29208 TENNESSEE Southern Poison Control Center 901-528-6048 848 Adams Ave. Memphis, TN 38103 2006 Integrated Orchard Management Guide for Commercial Apples in the Southeast Table of Contents Pest and Orchard Management Program . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Tree Row Volume: A Model for Determining Spray Volume . . . . . . . . . 27 IPM Practices for Selected Pests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Pesticide Resistance Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Effect of pH on Pesticide Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Orchard Floor Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Apple Pollination, Honey Bees, and Pesticides . . . . . . . . . . . . . . . . . . . . 38 Soil and Plant Analysis Guidelines for Southeastern Apple Production . 39 Fertility Management Recommendations for Apples . . . . . . . . . . . . . . . . 40 Relative Effectiveness of Fungicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Relative Effectiveness of Insecticides and Miticides . . . . . . . . . . . . . . . . 43 Toxicity of Pesticides to Beneficial Arthropods . . . . . . . . . . . . . . . . . . . . 45 Weed Response to Preemergence Herbicides . . . . . . . . . . . . . . . . . . . . . 46 Weed Response to Postemergence Herbicides . . . . . . . . . . . . . . . . . . . . . 47 Fungicides and Bactericides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Insecticides and Miticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Growth-Regulating Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Vertebrate Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Pesticide Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 EPA Registration Numbers of Various Materials . . . . . . . . . . . . . . . . . . . 75 Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of chemical products or services in this publication does not imply endorsement by the Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product before applying any chemical. For assistance, contact your local Extension Agent. Senior Editor: Jim Walgenbach, Extension Entomologist, NC State University Section Editors: Insect Management Jim Walgenbach Cultural/Growth Regulators Steve McArtney Disease Management Turner Sutton Vertebrate Management Dave Lockwood Weed Management Wayne Mitchem Contributors Alabama South Carolina John McVay Arlie Powell Ed Sikora Entomology Horticulture Plant Pathology Bob Bellinger Mike Hood Desmond Layne Guido Schnabel Safety Apiculture Horticulture Plant Pathology Arkansas Tennessee John Boyd Pat Fenn Donn Johnson Curt Rom Weed Science Plant Pathology Entomology Horticulture Steve Bost Edward Burgess Frank Hale Dave Lockwood John Skinner Plant Pathology Safety Entomology Horticulture Apiculture Georgia North Carolina Phillip Brannen Keith Delaplane Paul Gulliebeau Dan Horton Harold Scherm Plant Pathology Apiculture Safety Entomology Plant Pathology Steve McArtney Wayne Mitchem Mike Parker Bill Sullivan Turner Sutton David Tarpy Steve Toth Jim Walgenbach Horticulture Horticulture Horticulture Zoology Plant Pathology Entomology Entomology Entomology 1 Pest and Orchard Management Program DORMANT Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Control tree density, size, and shape for better light and spray penetration. Conduct annual dormant pruning in central leader trees and appropriate high-density orchards. ***** The younger the trees, the closer to bud break they should be pruned. Prune older and bearing trees first; prune 1- to 2-year-old nonbearing trees during the month before dormant bud break. Provide proper nutrition for moderate tree growth and good fruit quality. Collect soil samples; establish and maintain a good lime and fertility program. Apply late winter fertilizer to young, nonbearing trees, and half rate to mature, bearing trees. ***** See Fertility Management section (page 40) for complete sampling, fertilizer rates, and application methods. Apply full rate to young, nonbearing trees to promote good tree growth. Increase lateral bud break and lateral shoot development on last year's leader growth to encourage scaffold limb development. Bag last year's leader growth 3 to 4 weeks before anticipated dormant bud break. ***** See Growth-Regulating Chemicals section (page 61) for details. Plant Growth Regulators Control water sprout regrowth near pruning cuts and on tops of large scaffold limbs exposed to light by heavy dormant pruning. Tre-Hold A-112 See comments. Use 10,000 ppm (10 oz/gal) as a "sponge-on" application. 12 0 See Growth-Regulating Chemicals section (page 61) for complete recommendation details. The need for this practice depends on heaviness of pruning, size of cuts, and potential growth vigor. Effectiveness depends on COMPLETE coverage. Control burr knot formation. Gallex ** Paint directly from can, full strength, on burr knots. See Growth-Regulating Chemicals section (page 61) for recommendation details. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row volume of 400 gal/acre. 2 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Reduce inoculum of apple scab fungus. Shred leaves with flail mower. ***** May also help reduce inoculum of fungi that cause Brooks spot, Alternaria blotch, and Glomerella leafspot. Reduce inoculum of black, white, and bitter rot fungi. Prune out dead wood and mummied fruit. ***** Pruning is extremely important to reduce the likelihood of these diseases. Don’t stockpile prunings near orchard. Remove and burn, or chip with a flail mower. Reduce inoculum of fire blight bacteria. Prune out cankers and old fire blight strikes. **** Will also reduce inoculum of black rot, white rot, and bitter rot. Reduce inoculum of powdery mildew fungus. Prune out silver-colored terminals. *** Particularly useful on young trees of a susceptible cultivar. Improve control of cedar apple and quince rusts. Scout orchard, adjacent woods, or borders for red cedar, and remove. ***** Complete removal of red cedar in areas where cedars are not common may eliminate need for fungicide sprays for these diseases. Create good conditions for drying fruit and foliage; improve spray penetration. Prune to open trees. ***** Pruning is extremely important for good disease control inside the canopy and in the tops of large trees. Weed Management Control seedling perennials and winter annuals. Apply glyphosate or paraquat to control emerged winter annuals. ***** +++++ See product label. See product label. Apply nonselective postemergence herbicide alone (spring). When control from this breaks and summer weeds are 2-3 inches tall, apply a nonselective preemergence herbicide. This will likely be in early May, but may vary from year to year. Delaying PRE herbicide application results in residual control later in the summer. Reduce dandelions. 2,4-D amine ++++ 1 qt 1.0 lb 48 60 Apply at least 2 weeks before bloom to control flowering weeds. Reduces competition with apple blossoms to enhance bee pollination. Control of flowering weeds will also help control tarnished plant bug. 3 SILVER TIP Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control fire blight. Bactericides copper hydroxide copper oxychloride sulfate Bordeaux ++++ ++++ ++++ See label. See label. See label. See label. See label. See label. This treatment will help control fire blight in blocks of trees of a susceptible cultivar where fire blight has been a problem. It will not eliminate need for streptomycin. Applications later than 0.25- to 0.5-inch green tip may result in injury. Most effective if applied dilute. Control black rot. Fungicides Captan 50W or 4L ++++ ++++ —— 4 lb 2 qt 96 96 00 An important spray for black rot control in Georgia. Warning: Captan will cause injury when used with or too close to oil applications. Control crown rot (collar rot). Fungicides Ridomil Gold EC or WSP ++++ See label. 12 1 Ridomil and Aliette applications are recommended on cultivars propagated on susceptible rootstocks planted in heavy or poorly drained soils. Apply Ridomil in the spring before growth starts, and repeat application after harvest. Apply 3 to 5 applications of Aliette a year. Make first application of Aliette after leaf emergence. Note: Ridomil and Aliette must be applied on a preventive basis. Treatment of trees exhibiting symptoms will not prevent further symptom development. Aliette 80WDG or 80 WSP ++++ e to 1½ lb 2 to 5 lb 12 14 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 4 GREEN TIP TO ½-INCH GREEN Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate Per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab. See discussion in Fungicides and Bactericides (page 49) for information on postinfection control program. Fungicides Syllit 65 W +++++ ½ to ¾ lb 2 to 3 lb 48 7 Vangard 75WG +++++ 1.25 oz 5 oz 12 72 Vangard tends to be most active at cool temperatures. Vangard 75WG + mancozeb 80 WP or 75 DF or F4 or + Polyram 80DF +++++ +++++ +++++ +++++ +++++ ¾ oz ¾ lb ¾ lb 0.6 qt ¾ lb 3 oz 3 lb 3 lb 2.4 qt 3 lb 12 24 24 24 24 72 77 77 77 77 Scala SC +++++ 1.75 to 2.5 oz 7 to 10 oz 12 72 Scala SC is not compatible with captan. Scala SC + mancozeb 80 WP or 75 DF or F4 or + Polyram 80DF +++++ +++++ +++++ +++++ +++++ 1.25 oz ¾ lb ¾ lb 0.6 qt ¾ lb 5 oz 3 lb 3 lb 2.4 qt 3 lb 12 24 24 24 24 72 77 77 77 77 Sovran 50WG +++++ 1 to 1.6 oz 4 to 6.4 oz 12 30 Flint 50WG +++++ — 2 to 2.5 oz 12 14 Pristine 38W +++++ — 14.5 to 18.5 oz 12 0 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. GREEN TIP TO ½-INCH GREEN (Continued) 5 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate Per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Rubigan 1E + captan 50 WP or + mancozeb 80 WP or 75 DF or F4 or + Polyram 80DF +++++ +++++ +++++ +++++ +++++ 3 to 4 oz ¾ lb ¾ lb ¾ lb 0.6 qt ¾ lb 8 to 12 oz 3 lb 3 lb 3 lb 2.4 qt 3 lb 96 24 24 24 24 30 77 77 77 77 Do not use captan within 2 weeks of an oil spray. Although resistance of the apple scab fungus to the DMI fungicides Nova, Rubigan, and Procure has not been confirmed, some growers have experienced problems in the Southeast in controlling scab when using these fungicides. Growers who have had this problem should use a program that begins with two sprays of Syllit, Vangard, or Scala, followed by two sprays of Flint or Sovran. The fifth spray, which should occur around petal fall, can include a DMI fungicide, but it needs to be combined with a full rate of captan or captan + mancozeb or metiram to ensure scab control. A DMI fungicide at this time will help control powdery mildew, especially on mildew-susceptible varieties, and cedar apple and quince rust if captan is used alone. Nova 40W + captan 50 W or + mancozeb 80 W or 75 DF or F4 or + Polyram 80 DF +++++ +++++ +++++ +++++ +++++ 1¼ to 2 oz ¾ lb ¾ lb ¾ lb 0.6 qt ¾ lb 5 to 10 oz 3 lb 3 lb 3 lb 2.4 qt 3 lb 96 24 24 24 24 14 77 77 77 77 Procure 50WS + captan 50 W or + mancozeb 80 W or 75 DF or F4 or + Polyram 80W +++++ +++++ +++++ +++++ +++++ 1 to 2 oz ¾ lb ¾ lb ¾ lb 0.6 qt ¾ lb 4 to 8 oz 3 lb 3 lb 3 lb 2.4 qt 3 lb 96 24 24 24 24 14 77 77 77 77 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 6 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Insect Management Control scales and reduce overwintering European red mite and rosy apple aphid eggs. Improve scale and rosy apple aphid control Insecticides Oil Oil + Lorsban 4E or Supracide 2E or Esteem 35WP or Diazinon 50WP or Danitol 2.4EC or Asana XL or Ambush 2E or Warrior +++++ ++++ +++++ +++++ +++++ ++++ +++ +++ ++++ 2 gal 2 gal ½ to 1 pt 1 to 2 pt – 1.0 lb 2b to 5a oz 2 to 5.8 oz 1.6 to 3.2 oz 0.64 to 1.28 oz 8 gal 8 gal 2 to 4 pt 4 to 8 pt 4 to 5 oz 4 lb 10b to 21a oz 4.9 to 14.2 oz 6.4 to 12.8 oz 2.56 to 5.12 oz 12 12 96 12 12 24 24 12 12 24 0 0 DD DD 45 21 14 21 PF 21 Use a superior-type or highly refined summer oil applied dilute for best results. If the oil application is delayed until tight cluster to pink, use a refined oil or reduce a superior type to ½ to 1 gal/100 gal. Do not use captan within 2 weeks of an oil application. An insecticide with oil may be added at this time in orchards experiencing problems with scales or climbing cutworms. In some blocks, applications of Lorsban, Asana, and Ambush no longer control rosy apple aphid due to resistance. Neither Asana nor Ambush will control mites or scales. Note: Pyrethroids, including Asana, Ambush, Danitol, and Warrior will not control scales. These products are highly toxic to predatory mites and often lead to flare-ups of European red mite populations. Initiate Oriental Fruit Moth (OFM) monitoring program. Erect pheromone traps ***** Erect pheromone traps by green tip to detect first emergence. See section on IPM Practices for Selected Pests (page 29) for monitoring information. Mating disruption of OFM. Pheromones Isomate Rosso +++++ 100 dispensers /acre If insecticides are used for first generation OFM control at petal fall, mating disruption of OFM can be delayed until May or June. See section on “Mating Disruption” in IPM Practices for Selected Pests (page 31). 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. TIGHT CLUSTER TO PINK 7 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab. Fungicides Same fungicides as used in green-tip spray except do not use Vangard 75WG or Syllit 65W. If two sprays of Sovran or Flint have been used, switch to a nonstrobilurin fungicide. Control powdery mildew. Fungicides Nova 40W Rubigan EC Bayleton 50DF Procure 50WS +++++ ++++ ++++ +++++ 1¼ to 2 oz 3 to 4 oz ½ to 2 oz 1 to 2 oz 5 to 10 oz 8 to 12 oz 2 to 8 oz 4 to 8 oz 24 12 12 12 14 30 45 14 These are the most important sprays for the control of powdery mildew. Control cedar apple rust and quince rust. Fungicides Nova 40W Rubigan 1EC Bayleton 50DF mancozeb 80W or 75DF or F4 Polyram 80W Ferbam Granuflo +++++ +++++ +++++ +++++ +++++ +++++ +++++ ++++ 1¼ to 2 oz 3 to 4 oz ½ to 2 oz ¾ lb ¾ lb 0.6 qt ¾ lb ½ lb 5 to 10 oz 8 to 12 oz 2 to 8 oz 3 lb 3 lb 2.4 qt 3 lb 2 lb 24 12 12 24 24 24 24 24 14 30 45 77 77 77 77 7 Do not use Ferbam within 7 days of an oil spray. Control black rot and frogeye leafspot. Captan 50W or 4L ++++ ++++ 1 ½ to 2 lb ¾ to 1 qt 6 to 8 lb 3 to 4 qt 96 96 00 Captan alone will not control powdery mildew or rust diseases. Insect Management Initiate codling moth and leafroller monitoring program. Erect pheromone traps. ***** Erect traps now because moths begin to emerge near bloom. See section on IPM Practices for Selected Pests (page 29) for information on monitoring programs. 8 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv Interval 100 gal Acre (days) Comments Insect Management Control rosy apple aphid. Insecticides Actara 25WDG Assail 30SG Calypso 4F Thiodan 3EC, Phaser 3EC Diazinon 50W Dimethoate 4EC/400 Danitol 2.4EC +++++ +++++ +++++ +++ ++++ ++++ +++++ – – – b qt 1 lb ½ to 1 pt 2.6 to 4.3 oz 4.5 oz 2.5 to 4 oz 2 to 4 oz 2 b qt 4 lb 2 to 4 pt 10.6 to 21.3 oz 12 12 12 24 24 24 24 35 7 30 21 21 28 14 Pink stage is the best time to control rosy apple aphid. Caution: Rosy apple aphid resistance to Thiodan, Diazinon, Dimethoate, and Danitol has been observed in some orchards. See Rosy Apple Aphid resistance section (page 35). Assail may be used during bloom if sprays are applied before or after bees are in the orchard. Assail residues on leaves or flowers are not toxic to bees, but avoid spraying when bees are in the orchard. Control plant bugs and spotted tentiform leafminer (STLM). Maintain clean ground-cover. Insecticides listed for rosy apple aphid will aid in plant bug and leafminer control if plant bugs are readily seen. ***** In many instances, a clean groundcover eliminates the need for insecticides to control bugs. If there is a history of plant bug problems, a second application at petal fall will improve control. The need for insecticides specifically targeting STLM at this time is questionable because first generation mines rarely exceed threshold levels. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 9 BLOOM Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Loosen bags on leaders to acclimate for 2 to 3 days; then remove bags from leaders and spray with Promalin. Leader bags must be removed when new lateral growth is 1 to 3" long. ***** See Growth-Regulating Chemicals section (page 61) for complete details. Do leader selection and strip whorl on dormant headed tree leaders. Select new shoot for central leader and remove competing shoots from first four nodes below new leader shoot. Plant Growth Regulators Improve fruit shape and increase fruit weight of Red and Golden Delicious (can be used only on varieties that have dominant calyx ends). (BA+GA 4 + 7) Promalin Perlan +++ +++ 1 to 2 pt 1 to 2 pt 12 4 None See Growth-Regulating Chemicals section (page 61). Apply as a fine mist application at 40 to 50% of Tree Row Volume (TRV) water rate between king bloom opening and full bloom. Increase lateral bud break and lateral shoot growth on 1-year-old leader growth as a tool to encourage scaffold limb development, especially on those that were bagged before bud break. Promalin Perlan +++++ +++++ 250 to 500 ppm (1 to 2 pt)/10 gal 125 to 500 ppm (0.5 to 2 pt)/ 10 gal 12 4 None Apply to last year's leader growth with a handheld nozzle. See Growth-Regulating Chemicals section (page 61). Make one application when orchard trees have 1 to 3 inches of new growth. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 10 Goals Options Relative1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab, rusts, and mildew. Fungicides Same fungicides as recommended in tight cluster stage. Avoid sprays in full bloom if possible. Do not overextend application intervals. Control fire blight. Bactericides streptomycin 4.8 to 8 oz 1½ to 2½ lb 12 50 Begin application at first bloom and continue at 3- to 4-day intervals until petal fall. Streptomycin sprays protect only those blossoms open at time of application. It is very important to continue spraying through “rat-tail” bloom, especially on susceptible varieties. See discussion under Resistance Management section (page 34) for timing sprays according to conditions favorable for infection. Insect Management Protect pollinators. Do not apply insecticides during bloom. ***** Keep orchard floor free of flowering weeds. This will increase pollination activity in the trees and lessen bee activity after apple bloom. Disrupt mating of codling moth. Pheromones Isomate CTT CheckMate CM-XL 1000 ++++ ++++ (# dispensers) 200/acre 120-200/acre Do not use mating disruption in blocks of less than 5 acres. Pheromone dispensers should be hung before moths begin to emerge, with hanging completed by petal fall. Also, supplemental sprays with an insecticide may be necessary under moderate to high population densities. See section on IPM Practices for Selected Pests (page 29). 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. PETAL FALL 11 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Reduce fruit corking. Solubor +++ 1 lb at first cover If boron is low in leaf sample or cork spot has been a problem in past years, a second and third application may be used. Dilute applications are necessary for good uptake. See Fertility Management section (page 40). Reduce fruit corking and bitter pit. calcium nitrate or calcium chloride +++ +++ 3 lb 2 lb beginning at first cover Repeat calcium sprays in each cover spray all season. Calcium nitrate may contribute to unwanted leaf nitrogen levels and vegetative growth. Do not apply calcium chloride when temperatures are above 85ºF, and DO NOT tank mix with Solubor. All calcium sprays should be applied dilute for maximum response, especially for bitter pit control in the late season cover spray when fruit are becoming waxy. See Fertility Management section (page 40). Plant Growth Regulators Reduce fruit russetting on susceptible cultivars (esp. Golden Delicious). (GA4+7) Pro-Vide Novagib ++++ ++++ 10 oz/appl. 20-26 oz/appl. 12 4 None At petal fall, begin the first of four applications at 10-day intervals. See Growth-Regulating Chemicals section (page 61) for complete recommendations. Thin fruit to reduce crop load and encourage return bloom. Depends on cultivar, fruit size, and thinning chemical selected. Applications timed from petal fall to about 8 mm would be applied during this time. +++++ See Thinning Chart. Check label for specific thinning chemical(s) to be used. See Chemical Fruit Thinning Spray and Apple Thinning recommendations chart in Growth- Regulating Chemicals section (page 64). Initiate vegetative growth control applications. Apogee ++++ Use at TRV calculated A.I./acre. 12 45 See Apogee table in Growth-Regulating Chemicals section (page 66). 12 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management Control scab. Scout for secondary scab. ***** If primary scab is controlled by petal fall or first cover, switch to captan. If secondary scab is detected early, dodine, Rubigan, Nova, or Procure can be effectively used in a postsymptom treatment. See discussion under Fungicides and Bactericides (page 49). Control summer diseases (general). Fungicides captan 50W or 4L 2 lb 1 qt 8 lb 4 qt 96 96 0 0 If Rubigan, Nova, or Procure is used in this spray, increase the rate of Captan 50W to 6 to 8 lb/acre or Captan 4L to 3 to 4 qt/acre and extend interval to 10 to 14 days, or follow combination sprays with lower rates of captan or metiram in 5 to 7 days with full rate of captan or combinations of captan plus mancozeb or metiram. Captan and metiram at petal fall or first cover generally give better fruit finish than mancozeb. If the first cover spray occurs after May 15, include 8 to 12 oz/acre of Topsin M70WP with captan for sooty blotch or flyspeck control as directed in second and later cover sprays below. Use captan in orchards where black rot is a problem. captan 50W or 4L + Polyram 80 W or mancozeb 80W 75 DF 4F +++++ +++++ +++++ +++++ +++++ 1¼ lb 0.62 qt ¾ lb ¾ lb ¾ lb 0.6 qt 5 lb 2½ qt 3 lb 3 lb 3 lb 2.4 qt 96 96 96 96 77 77 77 77 Sovran 50WG +++++ 1.0 to 1.6 oz 4.0 to 6.4 oz 12 30 Sovran and Flint will also control apple scab and powdery mildew. PETAL FALL (continued) 13 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control summer diseases (general) (continued). Flint 50WG +++++ — 2.5 to 3.0 oz 12 14 Pristine 38W +++++ — 14.5 to 18.0 oz 12 0 Control Brooks fruit spot. Fungicides Use fungicides listed for summer diseases or use fungicide combinations listed under green tip. +++++ Petal fall through third cover sprays are the most important sprays for Brooks spot control. Nova, Rubigan, and Procure have very little Brooks spot activity. If Nova, Rubigan, or Procure are used, combine them with a full rate of protectant. Control powdery mildew. Fungicides Bayleton 50DF +++++ 0.5 to 2 oz 2 to 8 oz 12 45 If Nova, Rubigan, or Procure are no longer used, include Bayleton for mildew control on susceptible cultivars. Control cedar apple rust. Fungicides Ferbam Granuflo ++++ ½ lb 2 lb 24 7 If captan alone is used in these sprays, include Ferbam where cedar apple rust is a problem. Insect Management Preventively control European red mite, spotted tentiform leafminer, and white apple leafhopper. Control European red mite. Insecticides Agri-Mek 0.15EC + oil Apollo SC Savey 50WP Zeal 72WDG FujiMite5EC Envidor 2SC +++++ +++++ +++++ +++++ +++++ ++++ 2.5 oz S S S S S 10 oz 4 oz 3 oz 2 to 3 oz 1 to 2 pt 16 to 18 oz 12 12 12 12 12 12 28 45 28 28 14 7 An application of Agri-Mek at petal fall should provide season-long suppression of these pests. A paraffinic spray oil (0.25% or 1 gal/acre) must be tank mixed to ensure Agri-Mek’s activity. Do not use captan 2 weeks before or after applying oil with Agri-Mek. Apollo and Savey are most effective if applied at petal fall or first cover. Apply FujiMite, Zeal, or Envidor between petal fall and third cover or when mites reach one adult per leaf. FujiMite will also control leafhoppers. See page 35 for resistance management of European red mite. 14 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control plum curculio. Insecticides Guthion 50WP Imidan 70WP Avaunt 30WG Actara 25SDG Assail 30SG Calypso 4F Clutch 50WDG Sevin 50WP +++++ +++++ +++++ +++++ ++++ ++++ +++ ++++ ½ lb ¾ lb – – – 1 to 2 oz – ½ lb 2 lb 3 lb 5 to 6 oz 4.5 to 5.5 oz 8 oz 4 to 8 oz 3 oz 1 lb 48h, 14d 24 12 12 12 12 12 12 21 7 28 35 7 30 14 3 Adults enter orchards before or near petal fall. A preventive spray is recommended to minimize damage on fresh market apples. Cool weather during this period may extend adult activity, which may require a second application. Read about re-entry interval for Guthion in the Insecticides and Miticides section (page 52). Control Oriental fruit moth. Insecticides Guthion 50WP Imidan 70WP Avaunt 30WG Sevin 50WP Assail 30SG Calypso 4F Clutch 50WDG +++++ +++++ ++++ ++++ ++++ ++++ +++ ½ lb ¾ lb – ½ lb – 1 to 2 oz – 2 lb 3 lb 5 to 6 oz 2 lb 5 to 8 oz 4 to 8 oz 3 oz 48h, 14d 24 12 12 12 12 12 21 7 28 3 7 30 14 Oriental fruit moth has become more important in apples in recent years. An insecticide applied between 500 and 600 degree days (DD) after biofix will control the first generation. Read about re-entry interval for Guthion in Insecticides and Miticides Section (page 52). Control San Jose scale. Insecticides Dimethoate 4EC/400 Diazinon 50WP Guthion 50WP Esteem 0.86EC Centaur 70WP Assail 30SG summer oil +++++ +++++ ++++ +++++ ++++ ++++ +++ ½ to 1 pt 1 lb ½ lb – – – – 2 to 4 pt 4 lb 2 lb 4 oz 34.5 oz 8 oz 1 to 2% 48 24 48h, 14d 12 12 12 12 28 21 21 45 14 7 0 Where scales are a problem, apply an insecticide for first generation crawlers, which are active from petal fall through third cover. Yellow crawlers can be detected by wrapping double-stick tape around infested limbs after bloom and inspecting weekly. Caution: Diazinon or oil applied with captan or Captec may cause phytotoxicity. Control white apple leafhopper. Insecticides Sevin 50WP Actara 25WDG Assail 30SG Calpyso 4F Provado 1.6F Avaunt 30WG +++++ +++++ +++++ +++++ +++++ +++++ ½ lb – – 0.5 to 1 oz 1 oz – 2 lb 2 to 2¾ oz 2.5 to 4.0 oz 2 to 4 oz 4 oz 5 to 6 oz 12 12 12 12 12 12 1 35 7 30 7 28 Threshold level for first generation white apple leafhopper is 1 nymph per leaf. Thinning apples with Sevin during this time controls leafhoppers. Leafhoppers may be present from petal fall to second cover spray. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 15 PETAL FALL (continued) Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control spotted tentiform leafminer. Insecticides Lannate 90SP Actara 25WDG Provado 1.6F SpinTor 2SC Assail 30SG ++++ ++++ ++++ +++++ ++++ ¼ lb – 1 to 2 oz – – 1 lb 4.5 oz 4 to 8 oz 5 to 8 oz 1.1 oz 72 12 12 4 12 14 35 7 7 7 Threshold level for first generation leafminer is one mine per leaf, but rarely do populations reach this level this early in the season. Control rosy apple aphid. Insecticides Provado 1.6F Actara 25WP Assail 30SG Calypso 4F Dimethoate 4EC/400 Danitol 2.4EC +++++ +++++ +++++ +++++ ++++ ++++ 2 oz 4.5 oz – 0.5 to 1.0 ½ pt 2.6 to 5.3 oz 4 to 8 oz 4.5 oz 2.5 to 4.0 oz 2 to 4 oz 2 pt 10.6 to 21.3 oz 12 12 12 12 48 24 7 35 7 30 28 14 If an insecticide was not applied for rosy apple aphid at pink, or if control was poor, an insecticide should be applied. Caution: Diazinon applied with captan or Captec may cause phytotoxicity or russetting. Control green fruitworm. Insecticides Guthion 50WP Imidan 70WP +++++ +++++ ½ lb ¾ lb 2 lb 3 lb 48h, 14d 24 21 7 Green fruitworms are not a common pest: Apply an insecticide at petal fall if larvae are observed. Weed Management Control weeds. Check orchards for weed populations. ***** Identify weed problems so herbicide program can be adjusted for summer weed control. Apply Pre + Post herbicide. See herbicide guide. ***** See product labels. See product labels. Apply when summer weeds are 2 to 3 inches tall. Delaying application of preemergence herbicides until early May extends summer weed control. Suppress clover bloom to protect bees from insecticide sprays. 2,4-D ***** 1 qt 48 60 Apply 2,4-D 7 to 10 days before spraying insecticides to suppress clover and avoid killing bees. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 16 FIRST COVER Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Disease Management (Same fungicides as used in Petal Fall Spray) Insect Management Control codling moth. Monitor codling moth adult activity. Insecticides Guthion 50WP Imidan 50WP Intrepid 2F Rimon Danitol 2.4EC Esteem 35WP Assail 30SG Calypso 4F CYD-X ***** +++++ +++++ +++++ +++++ +++++ +++ ++++ ++++ ++++ ½ lb ¾ lb – – – – – 1 to 2 oz – 2 lb 3 lb 10 to 16 oz 20 to 40 oz 16 to 21a oz 4 to 5 oz 4 to 8 oz 4 to 8 oz 1 to 3 oz 48h, 14d 24 4 12 24 24 12 12 4 21 7 14 14 14 45 7 30 0 See IPM Practices for codling moth (page 29) to determine how to minimize insecticide applications for codling moth control. Most insecticides generally provide 2 weeks’ control, so do not be concerned if pheromone trap counts remain high 1 week after spraying. If using Intrepid, Rimon, or Esteem for first generaton codling moth, 2 applications at 14- day intervals should be made, the first at 100- 200 DD. Do not make more than 2 applications of Esteem per season. CYD-X is a virus that controls only codling moth. Frequent applications (7-14 days) at low rates (1 to 2 oz per acre) have worked well in field trials. Control rosy apple aphid, plum curculio, white apple leafhopper, spotted tentiform leafminer, and San Jose scale. Monitor orchards for these insects. Insecticides (See Petal Fall section, page 11) ***** Infestations of these insects may occur anytime from petal fall to the second cover spray. Early detection is important for effective control. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 17 SECOND COVER AND LATER SPRAYS Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Cultural Management Reduce fruit corking and bitter pit. calcium nitrate calcium chloride +++ +++ 3 lb 2 lb See information listed in Petal Fall to First Cover sections (pages 11 through 16) and Fertility Management section (page 40). Provide proper nutrition for moderate tree growth and good fruit quality. Apply second half of fertilizer to mature, bearing trees if crop load is present, as soon as frost/freeze danger is past (approx. second cover). Collect leaf samples in July to mid-August for leaf analysis. ++++ +++++ See Fertility Management Recommendations section (page 40) for fertilizer use suggestions and complete recommendations. See Fertility Management Recommendations section (page 40) for complete details. Achieve proper tree training, and control tree size and density for good light and spray penetration. Select lateral limbs, strip whorls, establish wide crotch angles with toothpicks or clothespins, and prop limbs to good limb angles (60-90º for central leader trees and 75-85º below vertical for high density, slender, spindle-type trees). Do detailed young tree management (deshoot, position limbs, tie up leader growth) every 6 to 8 weeks until full tree size and bearing are achieved (especially for high density orchards). ++++ ++++ Tree training is mandatory to develop proper lateral branching and limb position. Summer pruning is a necessary extension of tree training begun earlier. Summer pruning helps contain tree size and density, and proper limb selection and positioning encourage flower initiation. Remove water sprouts. Do leader manipulation, such as summer bending or snaking, every 18 inches of terminal growth extension. ++++ ++ Removing upright water sprout growth reduces tree density, allowing greater spray penetration and better light distribution for fruit quality and color development. Summer pruning and removal of water sprouts also help control sooty blotch and flyspeck. 18 Goals Options Relative 1 Effectiveness(+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Plant Growth Regulators Thin to reduce crop load and encourage return bloom. Depends on cultivar, fruit size, and thinning chemical selected. Application time from approximately 9 mm and larger would be applied from second cover on. +++++ See thinning chart. See Chemical Fruit Thinning Sprays (page 62) and Apple Thinning Recommendations chart (page 64) in Growth-Regulating Chemicals section. Enhance return bloom. Naphthaleneacetic acid (NAA) +++ See NAA Table in PGR Section (page 65). Control ground suckers around base of trunk. Tre-Hold A-112 Sprout Inhibitor Also use herbicides approved for sucker control. See comments in Herbicide section (page 59) for Rely, Gramoxone. ++++ Use 10,000 ppm (10 oz/1 gal) as a low-pressure, large-droplet handgun application. 12 0 See Growth-Regulating Chemicals (page 66) for specific recommendation details. Delay preharvest fruit drop and delay fruit maturity. ReTain +++++ 2 oz One 333- gram pouch per acre (50 grams a.i.). 12 21 Apply a single application 4 weeks before normal start of harvest for each variety. Fruit maturity and harvest date will be significantly delayed. See Growth-Regulating Chemicals (page 67) for recommendation details. Delay or reduce preharvest fruit drop or both. Preload NAA (Fruitone-N) ++++ 2 oz 4 days 4 Apply multiple applications of 5 ppm each week for the 4-week period prior to the normal start of the harvest period for each variety. NAA + 4 to 8 oz 4 days 4 Temporarily suppress any fruit drop by applying 10 to 20 ppm (depending on variety) of NAA. A second application can be applied 7 to 10 days later. See Growth-Regulating Chemicals section (page 67) for recommendation details. SECOND COVER AND LATER SPRAYS (continued) 19 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Reduce fruit russetting in susceptible varieties. Pro-Vide 10SG Novagib (continue applications started at petal fall) ++++ ++++ 60-100 g 20 oz per acre/appl 12 4 0 See Petal Fall to First Cover sections and Growth-Regulating Chemicals section (page 61) for recommendation details. Reduce fruit cracking of susceptible varieties (e.g., Stayman). Pro-Vide 10SG +++ 100-200 g 12 0 Begin applications in early to mid-June or as soon as cracking is observed. Repeat at 3-week intervals until harvest. See Growth- Regulating Chemicals section (page 61) for details. Novagib +++ 2 to 4 pt per acre/appl 4 Promote lateral branching of current season’s growth. Promalin +++ 0.8 oz/gal of water (125 ppm) 12 None See Growth-Regulating Chemicals section (page 61) or recommendation details. Disease Management Control summer diseases (white rot, bitter rot, black rot, sooty blotch, flyspeck, black pox). Scout orchard. Prune out fire blight strikes. ***** ***** Apply cover sprays at 10- to 14-day intervals. Use a 10-day interval during wet, rainy periods. If Topsin M is not used in cover sprays, it is important to combine captan with sufficient ziram to increase fungicide rate to 8 to 10 lb/acre in order to control sooty blotch and flyspeck. Be sure to observe 77-day preharvest interval when using metiram or mancozeb. When using a combination of captan and ziram, use approximately equal rates of each. Use captan where there is a history of white rot. Fungicides captan 50W 4L +++++ +++++ 2 lb 1 qt 8 lb 4 qt 96 96 0 0 ziram 76DF or 76WDG ++++ 2 lb 8 lb 48 14 Thiram 65W ++++ 1.7 lb 6.8 lb 24 0 Sovran 50WG +++++ 1.0 to 1.6 oz 4.0 to 6.4 oz 12 30 A maximum of four applications and 25.6 oz of Sovran 50WG can be used per acre per season. It is weak on black pox. Flint 50WG +++++ – 2.5 to 3.0 oz 12 14 A maximum of four applications and 11 oz of Flint 50WG can be used per acre per season. It is weak on black pox. 20 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control summer diseases (continued). Pristine 38W +++++ – 14.5 to 18.0 oz 12 0 A maximum of four applications and 72 oz of Pristine can be used per acre per season. Pristine has activity on strains of the Alternaria blotch fungus that are resistant to Sovran and Flint. It is weak on black pox. captan 50 W 4L + Topsin M70WP +++++ 2 lb 1 qt 2 to 3 oz 8 lb 4 qt 8 to 12 oz 96 1 ziram 76DF or 76WDG + Topsin M70WP +++++ 2 lb 2 to 3 oz 8 lb 8 to 12 oz 48 14 thiram 75WDG + Topsin M70WP +++++ 2 lb 2 to 3 oz 8 lb 8 to 12 oz 24 0 captan 50 W 4L + metiram 80DF or mancozeb 75DF + Topsin M70WP +++++ 2 lb 1 qt ¾ lb ¾ lb 2 to 3 oz 8 lb 4 qt 3 lb 3 lb 8 to 12 oz 96 77 77 77 Metiram and mancozeb cannot be used within 77 days of harvest. captan 50 W or 4 L + ziram 76DF, 76WDG or thiram 65WDG + Topsin M70WP +++++ 1 lb ½ qt 1 lb 1 lb 2 to 3 oz 4 lb 1 qt 4 lb 4 lb 8 to 12 oz 96 14 If thiram is used in this combination, the REI is 96 hours and the PHI is 0 days. Suppress necrotic leaf blotch on Golden Delicious. ziram 76W or WDG thiram 75WDG zinc oxide 39.8% +++++ ++++ +++++ 1 to 2 lb 1 to 2 lb 4 to 8 lb 4 to 8 lb 1 pt 48 24 0 14 0 0 Sprays from mid June through early August are most important. SECOND COVER AND LATER SPRAYS (continued) 21 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control powdery mildew. Scout orchard. ***** Determine need for additional fungicides based on the number of infections on newly unfolded leaves. Control Alternaria blotch. Sovran 50WG Flint 50WG +++++ +++++ 1 to 1.6 oz 4 to 6.4 oz 2.5 to 3 oz 12 12 30 14 Make first application of Flint or Sovran around third or fourth cover (mid June). Apply two additional applications at 10- to 14-day intervals. These applications will also control other summer diseases on Delicious. Use in conjunction with a preventive mite management program. Insect Management Control codling moth. Monitor pheromone traps weekly for adult activity. Insecticides (See First Cover.) ***** See IPM practices for codling moth (page 29) and Oriental fruit moth (page 30) to determine the need for and timing of insecticide sprays. Insecticides provide 2 weeks’ control, so do not be concerned if trap catches remain high 1 week after spraying. Keep trap bottoms clean, and replace lures monthly. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 22 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. interval 100 gal Acre (days) Comments Control Oriental fruit moth. Monitor pheromone traps weekly for adult activity. Insecticides Guthion 50WP Imidan 70WP Intrepid 2F Rimon 0.83EC Danitol 2.4EC Assail 70WP Calypso 4F Mating Disruption Isomate-M100 Isomate Rosso CheckMate OFM-F ***** +++++ +++++ ++++ +++++ +++++ ++++ ++++ +++++ +++++ +++++ ½ lb ¾ lb – – – – 1 to 2 oz 2 lb 3 lb 12 to 16 oz 20 to 40 oz 5 to 6 oz 1.7 to 3.4 oz 4 to 8 oz 100 160 0.3 to 2.5 oz 48h, 14d 24 4 12 12 12 12 21 7 14 14 28 7 30 See IPM practices for Oriental fruit moth (page 30) to determine the need for and timing of insecticide sprays. Oriental fruit moth has become more important on apples in recent years, particularly later generations in August and September. Under moderate to low OFM populations, pheromone treatment should begin just before emergence of third generation adults (late June to early July). When OFM populations are high, begin mating disruption just before emergence of second generation adults (late May to early June). Control tufted apple bud moth. Monitor pheromone traps weekly for adult activity. Thin fruit to avoid excessive clustering. ***** **** See IPM Practices for tufted apple bud moth (page 31) to determine the proper timing of insecticide applications. Clustering of fruit is conducive to higher levels of tufted apple bud moth injury. Insecticides Intrepid SpinTor 2SC Danitol 2.4EC Avaunt 30WDG Rimon 0.83EC +++++ +++++ +++++ ++++ ++++ – – – – – 6 to 12 oz 4 to 8 oz 10.6 to 21.3 oz 5 to 6 oz 20 to 40 oz 4 4 24 12 12 14 7 14 28 14 See Insecticide Resistance Management section (page 35) for tufted apple bud moth (TABM). Insecticide sprays for TABM are recommended only in orchards with a history of damage. See section on IPM practices for tufted apple bud moth to properly time sprays. Bacillus thuringiensis Dipel 2X CryMax XenTari +++ ¼ to ½ lb ¼ to ½ lb ¼ to ½ lb 1 to 2 lb 1 to 2 lb 1 to 2 lb 4 4 4 0 0 0 For best results apply Bacillus thuringiensis (Bt) products at no less than 2X concentration. If using Bts, it is important to monitor codling moth with pheromone traps because Bts do not control codling moth. SECOND COVER AND LATER SPRAYS (continued) 23 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control apple maggot. Erect red sticky spheres in early June to monitor adults. **** Apple maggot has increased in importance in recent years and is particularly a problem in orchards near unsprayed orchards and/or following a year in which many orchards did not receive a full-season spray program, but still had some fruit in the orchard. Erect sticky traps on outside rows nearest abandoned orchards or other sources of flies. Check weekly. Threshold level is one fly per trap per week. If flies are still caught 2 weeks after spraying, apply again. Adults can emerge from June through August. Insecticides Guthion 50WP Imidan 70WP Assail 30SG Calypso 4F Clutch 50WDG Provado Surround WP +++++ +++++ ++++ ++++ ++++ +++ +++ ½ lb ¾ lb – 1 to 2 oz – – – 2 lb 3 lb 8 oz 4 to 8 oz 6 to 8 oz 4 to 8 oz 20 to 50 lb 48h, 14d 24 12 12 12 12 4 21 7 7 30 14 7 – Apply insecticides at 10- to 14-day intervals during apple maggot flight. Apply Surround at 7- to 14-day intervals, or after a heavy rain, because thorough, uniform, and consistent coverage is important. Rate of Surround will vary with tree size. Control white apple leafhopper or potato leafhopper. Insecticides Provado 1.6F Actara 25WDG Assail 30SG Calypso 4F Avaunt 30WG Dimethoate 4EC/400 Clutch 50WDG Centaur 70WP +++++ +++++ +++++ +++++ +++++ +++ +++++ +++++ 1 oz – – 0.5 to 1 oz – ½ pt – – 4 oz 2 to 2¾ oz 2.5 to 4.0 oz 2 to 4 oz 5 to 6 oz 2 pt 2 oz 34.5 oz 12 12 12 12 12 48 12 12 7 14 7 30 28 28 14 14 Threshold level for second brood nymphs (which occur in late July to early August) is one nymph per leaf. Treatment will eliminate the need to treat for adults immediately before harvest. Generally, low rates of insecticides will control leafhoppers. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry interval (hours) Preharv. interval 100 gal Acre (days) Comments 24 Control spotted tentiform leafminer. Insecticides Lannate 90SP SpinTor 2SC Vydate 2L Provado 1.6F Actara 25WDG Assail 30SG Calypso 4F Clutch 50WDG ++++ +++++ ++++ +++ ++++ ++++ ++++ ++++ ¼ lb – 1 to 2 pt 2 oz – – 0.5 to 1 oz – 1 lb 4 to 8 oz 4 to 8 pt 8 oz 4.5 oz 2.5 oz 2 to 4 oz 3 oz 72 4 48 12 12 12 12 12 14 0 14 7 14 7 28 14 A threshold level of two mines per leaf for second generation larvae (June to July) should be used to dictate the need for STLM control. Control of third generation larvae (August) may be necessary on late-maturing cultivars if populations exceed 4 mines per leaf. Many orchards have high levels of parasites by this time. Insecticides are more effective against sap-feeding mines than tissue feeders. Control green apple and spirea aphids. Insecticides Dimethoate 4EC/400 Provado 1.6F Actara 25WDG Assail 30SG Calypso 4F Clutch 50WDG +++++ +++++ +++++ +++++ +++++ +++++ ½ pt 1 to 2 oz –– 0.5 to 1 oz – 2 pt 4 to 8 oz 4.5 oz 2.5 to 4.0 oz 2 to 4 oz 2 oz 48 12 12 12 12 12 28 7 35 7 28 14 Threshold level for green apple aphid is 50% infested terminals. Control is most important on young trees and in dwarf plantings. On mature trees, a higher threshold is tolerable. Control Comstock mealybug. Insecticides Diazinon 50WP Dimethoate 4EC Actara 25WDG Assail 30SG +++++ +++++ +++ +++++ 1 lb ½ pt –– 4 lb 2 pt 4.5 oz 4 to 8 oz 24 48 12 12 14 28 35 7 Applications should be made near the third cover spray. Comstock mealybug has become a problem in some orchards where organophosphate use has been reduced or eliminated, where postbloom pyrethroid use has increased, or both. Control woolly apple aphid. Insecticides Dimethoate 4EC/400 Diazinon 50W +++ +++ ½ pt 1 lb 2 pt 4 lb 48 24 28 21 In recent years woolly apple aphid has increased in many areas. Above-ground infestations are of greatest concern on younger trees. Control redbanded leafroller. Insecticides Bacillus thuringiensis Guthion 50WP Imidan 70WP Intrepid 2F SpinTor +++ ++++ ++++ +++++ +++++ ¼ lb ½ lb ¾ lb – – 1 lb 2 lb 3 lb 8 to 10 oz 4 to 8 oz 12 48h, 14d 24 4 4 0 21 7 14 7 Redbanded leafroller is a sporadic problem. If damage is done, it is usually by the last generation, which lays eggs from mid August to mid September. Control lesser apple worm. Insecticides Guthion 50WP Imidan 70WP Intrepid 2F +++++ +++++ +++++ ½ lb ¾ lb – 2 lb 3 lb 10 to 16 oz 48h, 14d 24 4 21 7 14 Lesser apple worm is a sporadic pest of importance in isolated areas. If damage occurs, it is usually by the third generation, which occurs in August. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. SECOND COVER AND LATER SPRAYS (continued) 25 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Control dogwood borer. Insecticides Lorsban 50W, 4E Thiodan 3EC Asana XL ++++ +++++ +++ +++ 3 lb 1.5 qt a qt 2.0 to 5.8 oz – – – – 96 96 24 24 28 28 21 21 Apply insecticides with a handgun sprayer to the trunk, especially to burr knots and graft unions. Moths can lay eggs from mid May through July, so treatment in mid to late May is optimal. Lorsban should be applied with a handgun sprayer from no more than 4 ft or with a shielded sprayer to prevent drift onto foliage or fruit. Control European red mite and two-spotted spider mite. Monitor trees for mite activity. ***** See IPM practices for European red mite. European red mite and two-spotted spider mite threshold levels before July are 7 mites per leaf (85% infested leaves) and 10 mites per leaf (90% infested leaves) during July and August. If populations are near threshold level and Stethorus punctum is present, recheck in 3 to 4 days to determine if biological control reduces mite populations. In orchards with Alternaria blotch, a threshold of 2 mites per leaf (70 to 75% infested leaves) should be used to minimize stress to trees. Miticides Acramite 50WS Nexter 75WP Apollo SC Savey 50DF Zeal 72WDG Envidor 2SC Kelthane 50WP Vendex 50W Danitol 2.4EC wettable sulfur summer oil +++++ +++++ +++++ +++++ +++++ +++++ ++++ ++++ ++++ + ++ – – – – – – ¾ to 1½ lb ¼ lb – 1 ½ to 3½ lb ½ to 1 gal ¾ to 1 lb 4.4 oz 4.0 oz 3.0 oz 2 to 3 oz 16 to 18 oz 3 to 6 lb 2 lb 16 to 21.6 oz 5 to 15 lb ½ to 1% soln. 12 12 12 12 12 12 12 48 24 12 12 7 25 45 28 28 14 7 14 14 7 0 If Apollo or Savey were used at petal fall, do not reapply at this time. Use the higher rate of Kelthane on large trees. Do not expect complete control with a single application of oil or sulfur. These materials must be applied multiple times for best results. Applying a highly refined summer oil when mite populations are beginning to increase (first and second covers) will help suppress European red mite infestations. Do not apply captan 2 weeks before or after an oil spray. SECOND COVER AND LATER SPRAYS (continued) 26 Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Weed Management Spot-treat with herbicide to control difficult-to-manage perennial weeds. glyphosate ***** See Weed Response to Herbicide table (pages 46 to 48). Apple trees are especially sensitive to glyphosate applied in late summer and fall. Avoid contacting tree bark and especially foliage. . POSTHARVEST Goals Options Relative 1 Effectiveness (+) or Importance (*) Rate per2 Re-entry Interval (hours) Preharv. Interval 100 gal Acre (days) Comments Plant Growth Regulators Control fruit storage scald. DPA ++++ 2½ pt per one gal of water as a dip or spray to harvested fruit. See Growth-Regulating Chemicals section (page 61) for complete details. To maintain apple flesh firmness, fruit acidity and minimize scald SmartFresh See Growth-Regulating Chemicals section (page 61) for complete details. Weed Management Apply POST or PRE + POST herbicide. See herbicide guide. *** See herbicide guide. See product labels. In areas where heavy populations of winter annual weeds are present, apply herbicide as part of vole management program. Application of a fall preemergence herbicide will delay the spring herbicide application to early May or later. 1Effectiveness ratings range from + = poor control to +++++ = excellent control. Importance ratings range from * = minor importance to ***** = very important. 2Rates expressed as amount per 100 gal for dilute and amount per acre are for concentrate applications based on a tree-row-volume of 400 gal/acre. 27 Tree Row Volume (TRV): A Model for Determining Spray Volume The TRV model is a simple and objective method of determining (1) the volume of tree canopy on an acre of orchard, regardless of row spacing, tree size, age, or other factors; and (2) the dilute application water rate and chemical quantity for dilute (1X) applications or concentrate chemical load per acre needed to effectively spray each particular orchard, regardless of pruning and tree canopy density. The TRV concept rests on these assumptions: Each row of trees is a wall of foliage, and water and chemical loads required can be related to the volume and density of foliage within that wall. Only three measurements must be made: (1) The distance between rows of trees; (2) the maximum tree height to be sprayed; and (3) the spread from drip line to drip line, which must be accurately measured to at least the nearest foot. In addition, an assessment of tree density is needed to calculate the TRV of an orchard. Using these measurements, the TRV of any orchard can be calculated using the following formula: Step 1: 43,560 sq ft/acre = feet of row/acre distance between rows (ft) Step 2: Feet of row/acre (from Step 1) X tree height (ft) X cross-limb spread (ft) = cu ft of foliage/acre. Steps 1 and 2 determine the volume of foliage canopy per acre in the orchard. Step 3: Select one of the numbers from Table 1 that best indicates the canopy density of each separate orchard or block. The cubic feet of foliage volume from Step 2 and the tree density established in Step 3 are used to calculate the water volume required per acre for a dilute spray application to provide maximum chemical load with a dilute airblast sprayer (applied to runoff). canopy Step 4: cu ft of foliage/acre density gallons of dilute solution (from Step 2) X (from Step 3) = to be applied per acre for 1,000 cu ft a maximum application Example Consider an orchard that has rows spaced 25 feet apart, trees 20 feet high, a spread of 17 feet from drip line to drip line, and a tree density of 0.85. Step 1: 43,560 ft2 25 ft = 1,742.4 ft Step 2: 1,742.4 ft X 20 ft X 17 ft = 592,416 cu ft Step 3: Density has been given as 0.85 gal/1,000 cu ft Step 4: 592.416 cu ft X 0.85 gal = 503.5 gal/acre will apply a dilute 1,000 cu ft application to runoff. However, general pesticide applications are not applied to runoff. Using 70 percent (0.70) of the “to runoff” calculated rate reduces the dilute application just to the point of drip, or what we call “pesticide dilute.” Table 2 gives the adjustments to the “TRV calculated water rates for dilute to runoff” water application rate for various chemicals used and types of spray applications. The 503.5 gallons per acre in the example above is used to illustrate the adjustments in Table 2. Table 1. Canopy density adjustments in tree row volume (TRV) model. 0.70 gal/1,000 cu ft Trees extremely open, light visible through entire tree, less than 15 scaffold limbs per tree or young tree. 0.75 gal/1,000 cu ft Trees very open, 18 to 21 scaffolds per tree, light penetration throughout tree, healthy spurs within tree canopy. 0.80 gal/1,000 cu ft Trees well pruned, adequate light in trees for healthy spurs throughout trunk and scaffold limbs, many holes or openings in foliage where light is visible through tree. 0.85 gal/1,000 cu ft Trees moderately well pruned, reasonable spur population within canopy, tree thick enough that light is not visible through bottom b of tree. 0.90 gal/1,000 cu ft Trees pruned minimally, spurs inside canopy are weak due to limited light, very few openings where light is visible throughout the tree. 0.95 gal/1,000 cu ft Little or no pruning, spurs dead or very weak in canopy, very little light visible throughout the tree. 1.00 gal/1,000 cu ft Tree unpruned, extremely thick, no light visible anywhere through tree canopy, trees more than 20 ft high. 28 Table 2. Adjustments in tree row volume (TRV) calculated water rates per acre for various chemicals and types of spray applications. Type of spray and chemical application % of the calculated TRV dilute to runoff gallonage to be used for a dilute application Actual gallons/acre to be used in previous TRV example orchard 1Pre-petal fall dilute pesticide application (adjusted because of incomplete foliage development) 56 282 Dilute pesticide application (from petal fall on and all other applications not specifically mentioned) 70 352 ProVide and Promalin (as a fine mist) 40 to 50 201 to 252 Spur Red Delicious thinners and dormant oil applications 100 504 Thinners for other varieties 70 to 90 352 to 453 Vegetative growth inhibitor 80 to 90 403 to 453 Preharvest Ethrel plus stop-drop spray 100 to 120 504 to 605 1To use this reduced gallonage requires accurate nozzling to top of trees and good air displacement within trees (i.e., reduced tractor speed). Table 3. How to calculate concentrate application rates. Concentrate pesticide application (3X water rate)1 Dilute pesticide TRV gallonage = 352 gal/acre = 117 gal/acre Concentrate rate 3X Concentrate pesticide chemical load per acre (2X to 4X)2 Rate of pesticide Dilute pesticide per 100 gal x TRV gal/acre = 2.0 X 352 = 7.1 lbs/acre 100 gal 100 5X or greater3 Rate of pesticide Dilute pesticide per 100 gal x TRV gal/acre x 0.8 = 2.1 X 352 X 0.8 = 5.6 lbs/acre 100 gal 100 1Assume the example orchard was to be sprayed at 3X concentration. 2Rate per 100 gal dilute. Example based on 2.0 lb pesticide/100 gal. 3This adjustment for concentrate application (5X or greater) should be made if spraying conditions are good and trees are properly matched to the sprayer. Adequate spray coverage cannot be assumed with concentrate application if sprays are applied during windy conditions or to thick, oversized trees. Table 3 demonstrates how the chemical load and water volume for concentrate sprays can be easily calculated from the TRV model. The TRV model is accurate for dilute and concentrate chemical applications with conventional airblast sprayers, using water volumes as low as 150 gallons per acre. Below this gallonage, the physics of droplet size and impingement on the foliage can become a limiting factor in obtaining effective deposition on trees. Thus, if the TRV model calculates a water application rate of less than 150 gallons per acre, a 150 to 200 gallon rate should be considered a minimum in a conventional airblast sprayer, or be sure you are using a concentrate engineered sprayer (higher air speed) that will ensure adequate impingement of the spray solution on the tree surfaces at low water volume. Dwarf High-Density Orchards Dwarf high-density orchards represent a special situation for TRV applications. Most high density orchard TRV water application rates calculate out at well below the minimum desirable gallonage for good droplet impingement (below 150 gallons/acre). We have consistently found improved efficacy of pesticide application and improved time efficiency by calibrating for double the TRV. This raises the water application rate above the minimum desirable gallonage, and then you must drive every other row middle to reduce actual water volume per acre of orchard back to true TRV calculated rate. Pesticides are applied on a normal interval, alternating drive middles. The reality of sprayer calibration and nozzling for chemical applications is that until the proper chemical load is appropriately delivered and deposited on leaf and fruit surfaces, the spray you apply cannot be considered an effective pesticide application. 29 IPM Practices for Selected Pests Plum Curculio Plum curculio adults overwinter in leaf litter in and around orchards. In the spring when the daily maximum temperature exceeds 70ºF, adults emerge, mate, and lay eggs under fruit skin. This occurs near bloom, petal fall, or both, and an insecticide application at petal fall is important to minimize damage when adults are present. Adults are ¼-inch-long weevils with a curved snout; they are mottled black, gray, and brown with two bumps on each wing cover and a white marking across the back. Eggs hatch within a few days after being laid and feed in the fruit. The mature larva is ¼-inch long, white, slightly curved, and legless. Damage on apples is usually observed as feeding or oviposition scars and is cosmetic. There are two generations per year. Scouting and Control: After bloom, check twice weekly for plum curculio adults for feeding and egg-laying scars. Typically, an insecticide at petal fall and first cover (if adult emergence is protracted) is used for control. However, additional insecticides should be applied if any new damage is observed. Plum Curculio Degree-Day (DD) Model A degree-day model can help growers prepare for plum curculio emergence and determine the end of adult movement in the spring. Once buds swell, note the second date when air temperature exceeds 70ºF (biofix) and begin accumulating daily degree days (DD) (base 50ºF) using the DD table for codling moth on page 33 (base 50oF). Adults enter orchards from 50 to 400 DD after biofix. Damage occurs from 100 to 700 DD after biofix. Summer generation adults begin emerging after 1,100 DD and can cause damage until harvest. Apple Maggot Historically, the apple maggot has been a sporadic pest of apples in the southeastern U.S., but when it does occur it can cause considerable damage. The apple maggot usually completes one generation per season, but two generations are known to occur in some years. Adult flies emerge from overwintering pupae in the soil from June through September, with the major emergence period being from mid July to early August. About 7 days after emergence, flies become sexually mature and mate, after which females deposit eggs under the skin of apples by puncturing apples with their ovipositor. After a few days a small maggot hatches from the egg, and the maggot tunnels within the fruit. When mature, the maggot exits the apple, drops to the ground, and burrows into the soil, where it completes development and forms a pupa. The pupa is the overwintering stage, and it emerges as a fly the following summer. Although the majority of overwintering pupae emerge the following spring, some pupae do not emerge for 2 to 4 years. Weather conditions are important in dictating the timing and length of fly emergence. Pupae overwintering in lighter soils and in sunny areas emerge before those in heavier soils and shady areas. Sufficient soil moisture is also necessary for flies to emerge from soil-borne pupae; drought delays or prevents many flies from emerging. Abandoned orchards (or even a few nonsprayed trees) and wild hawthorn trees are potential sources of large numbers of flies and are a threat to commercial orchards located within at least 400 yards. Monitoring and Control: Monitor apple maggot adults with red sticky spheres alone or in combination with a volatile bait. Baited spheres catch two to four times as many adults as nonbaited spheres. In orchards with no history of maggot injury, a minimum of three red spheres should be placed on the outside row of an orchard closest to the suspected source of flies (e.g., abandoned orchard). Hang spheres in trees with fruit, but remove fruit adjacent to the sphere so that the sphere is clearly visible. Apply an insecticide within 7 to 10 days after catching the first fly, and repeat applications at 10- to 14-day intervals while adults are active. Codling Moth Codling moths begin to emerge and mate during April or early May, depending on location. Eggs generally begin to hatch near the first cover spray, and soon larvae tunnel into and feed inside fruit. The mature larvae are similar to Oriental fruit moth larvae, being ½-inch long and pinkish-white with legs. Unlike the OFM, codling moth larvae do not have an anal comb. Codling Moth Degree-Day Model Base a decision to spray insecticides against coding moth on pheromone trapping and the codling moth degree-day model. Use pheromone traps to determine the starting point of the model (biofix) and to gauge the intensity of populations. The degree-day model predicts percent of adult emergence and egg hatch for each of the three to four generations of codling moth that annually occur in the Southeast. To use the model, begin to accumulate degree days when male flight begins in the spring, which is referred to as biofix. The biofix date is determined with pheromone traps to detect the first sustained catch of two or more moths in the spring. Traps should be placed in orchards near the tight cluster stage of bud development, and checked one to two times per week. Traps should be hung at a density of one trap per 10 acres of orchard. Traps hung in the upper third of the canopy often catch more moths than those in the lower canopy. Once biofix is determined, degree days are calculated daily. It is only necessary to check traps once per week after biofix is determined. The table on page 33 should be used to determine the number of degree days occurring at various maximum and minimum daily temperatures. First Generation: Recommendations are provided for low and moderate to high population densities. Low-density orchards are those with less than 0.5 percent of the fruit damaged 30 the previous year and pheromone trap catches that do not exceed 10 moths per trap per week anytime before the accumulation of 200 DD after biofix. In low-density orchards, make a single insecticide application at 350 DD after biofix. In moderate- to high-density orchards, apply two insecticide applications 14 days apart, the first at 150 to 250 DD after biofix: 150 if using a product which depends primarily on ovicidal activity for control (i.e., Confirm or Intrepid), and 250 if using an insecticide that has contact activity against larvae (i.e., organophosphate or pyrethroid). Relationship between degree-day accumulations from biofix and percentages of codling moth adult emergence and egg hatch. Cumulative Degree Days % Adult Emergence % Egg Hatch Cumulative Degree Days % Adult Emergence % Egg Hatch 0 (biofix) 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1,000 1,050 1,100 1,150 1,200 1,250 1 5 15 27 40 52 63 72 80 87 91 95 97 98 99 99 100 0 1 2 5 8 13 18 26 35 0 0 0 0 0 3 9 18 30 42 54 64 73 81 87 92 95 97 98 99 100 0 1 2 3 6 1,300 1,350 1,400 1,450 1,500 1,550 1,600 1,650 1,700 1,750 1,800 1,850 1,900 1,950 2,000 2,050 2,100 2,150 2,200 2,250 2,300 2,350 2,400 2,450 2,500 2,550 43 52 60 68 77 80 85 89 92 95 97 99 0 2 4 7 10 15 20 25 31 38 45 52 59 65 10 15 21 28 36 45 63 62 69 75 81 85 89 92 95 94 99 100 3 5 8 12 16 21 27 31 Second Generation: Recommendations are provided for extremely low, low, and moderate to high population densities. Extremely low-density orchards may not require an insecticide application (i.e., pheromone trap catches never exceed three moths per trap per week between 900 to 1,900 DD after biofix for codling moth or 800 to 1,600 DD after biofix for Oriental fruit moth). Low-density orchards require one insecticide application at approximately 1,250 DD. These orchards may have no sign of damage by first generation larvae and trap catches between 3 to 7 moths per trap per week between 900 to 1,450 DD after biofix. Moderate- to high-density orchards will have fruit damage, higher pheromone trap catches requiring two insecticide applications 14 days apart starting about 1,250 DD after biofix. Third Generation: Apply an insecticide at 2,250 DD after biofix if pheromone trap catches exceed 5 moths per trap per week after 1,900 DD after biofix or if fruit damage caused by second-generation larvae is observed. Exceptions to the Model: Where codling moth populations are extremely high and where pheromone trap catches remain high between generations, additional insecticide applications may be necessary. This often occurs in orchards adjacent to an abandoned orchard or where old bins are placed near an orchard. Insecticides recommended for codling moth have sufficient residual activity so that applications made at 14-day intervals usually provide adequate protection. Oriental Fruit Moth Oriental fruit moths begin to emerge and mate before apple bloom, and eggs begin to hatch at petal fall. Variable spring temperatures cause erratic emergence and egg-laying by first-generation moths. The larvae feed on shoot tips and inside apple fruit. The mature larva is 1/2-inch long, pinkish-white, and has an anal comb and legs. The only way to distinguish between Oriental fruit moth and codling moth larvae is to use a hand lens to examine mature larvae for the presence of an anal comb. Codling moth larvae do not have an anal comb. Oriental Fruit Moth Degree-Day Model Base a decision to spray insecticides against Oriental fruit moth on pheromone trap catches and a DD model. The biofix is determined in the same manner as for the codling moth. Use pheromone traps to determine the starting point of the model and to gauge the intensity of populations. The degree-day model predicts adult emergence and egg hatch for the first three generations of the four or five generations that occur in the Southeast. However, generations overlap in the late season, which makes the degree-day model less useful later in the season. The table on page 33 uses daily maximum and minimum temperatures to determine daily DDs for Oriental fruit moth (base 45ºF). Place traps in the orchards near the green-tip stage of bud development, and check one to two times per week. Hang traps at eye-level at a density of 1 trap per 10 acres of orchard. Check traps weekly after the biofix date. First-Generation OFM: Control of the first generation is often important to prevent first-generation damage and to reduce populations of subsequent generations. First-generation egg laying is usually low on apple, and only one insecticide application between 400 and 500 DD after biofix is necessary, which usually coincides with petal fall. 31 Second-Generation OFM: If first-generation control was successful, second-generation populations are usually very low. Extremely low-density orchards may not require an insecticide application (i.e., pheromone trap catches never exceed 3 moths per trap per week between 800 to 1,600 DD after biofix). In low-density orchards (3 to 7 moths per trap per week caught between 800 and 1,500 DD), make a single insecticide application at 1,400 DD. Moderate- to high-density orchards will have fruit damage, higher pheromone trap catches, or both, and may need two insecticide applications 14 days apart starting at 1,100 DD. Third-Generation OFM: An insecticide is recommended at 2,200 DD after biofix if pheromone trap catches exceed 5 moths per trap per week at 1,900 DD after biofix and if there is fruit damage caused by the second generation. Fourth-Generation OFM: Because of overlapping generations late in the season, it is difficult to predict when egg hatch of the fourth generation begins. However, continuous egg laying can occur from August through October, and the use of pheromone traps are the best method to determine the potential for late-season damage. Apply an insecticide within 7 to 10 days of a pheromone trap threshold of 10 moths per trap per week. Maintain spray intervals on a two-week (complete) or 5- to 7-day (alternate-row-middle) schedule for as long as the threshold is exceeded. Tufted Apple Bud Moth The tufted apple bud moth (TABM) is the most important leafroller occurring in the Southeast. TABM completes two generations per year, with egg laying occurring during June (first generation) and August and September (second generation). Larvae feed on leaves and fruit, with fruit damage usually observed as surface feeding. However, second-generation larvae often feed within the calyx end of fruit. Unless an individual orchard has a history of damage by this insect, it is doubtful that special precautions need to be taken. Timing is critical to the successful management of this pest. Depending on the type of insecticide used and the intensity of the TABM population, one or two applications during each of the two generations may be necessary. Maintain a clean orchard floor, particularly in the early spring before bloom, to minimize TABM populations by removing the food source for overwintering larvae. New apple sucker growth and broadleaf weeds are important food sources in the spring. In recent years TABM populations have been reduced to very low numbers because of new insecticides used in many orchards Tufted Apple Bud Moth Degree-Day Model A TABM degree-day model similar to that of the Oriental fruit moth and codling moth has been tested and modified for populations in the Southeast. For calculating degree days from maximum and minimum daily temperatures, use the Oriental fruit moth table on page 33 (45oF). Place TABM pheromone traps at the tight cluster to pink stage of bud development at a density of 1 trap per 20 acres of orchard. Biofix is the first date on which a sustained catch occurs and may vary from 2 to 15 moths per trap over a one-week period. The cumulative number of degree days from the point of biofix is used to predict percentage of egg hatch and to time insecticide applications against the first generation. First-Generation Recommendation: When population densities are sufficiently high or if a short residual insecticide is used, two insecticide applications per generation are necessary; make the first application at about 10 percent egg hatch, which occurs between 800 and 900 DD after biofix, and the second application 14 days later. Where populations are low or if using a long residual insecticide, one application per generation should be made, and this can occur anytime between 10 and 30 percent egg hatch of the first generation, or from 800 to 1,200 DD after biofix. Second-Generation Recommendation: Depending on variety and harvest date, make one or two applications for second-generation control. For cultivars harvested by early September, a single application at 10 percent egg hatch will usually suffice; this coincides with the accumulation of about 2,600 DD after biofix (early to mid-August). Second-generation egg hatch can sometimes extend into late September, so a second application may be made in late August or early September on varieties harvested after mid- September. Mating Disruption Mating disruption programs consist of emitting relatively large amounts of sex pheromone into an orchard environment to disrupt the normal mate-location process. Mating disruption prevents mating and the subsequent laying of fertile eggs, which effectively reduces populations below economically damaging levels. It is effective only in blocks of 5 acres or more. In apples, mating disruption is registered for control of both codling moth and Oriental fruit moth. Oriental fruit moth is much easier to control with mating disruption compared with codling moth; against moderate to high codling moth populations, both mating disruption and insecticides should be used. Time insecticide applications to coincide with egg hatch of the target pest. High population densities of Oriental fruit moth have been successfully controlled with pheromones alone. Mating disruption will not control infestations resulting from immigrating fertilized female moths; hence, mating disruption alone is not recommended in blocks located adjacent to a likely source of immigrating moths (i.e., abandoned orchards or bin storage areas). Pheromone Dispensers: A number of companies market pheromone dispensers for mating disruption, including hand-applied dispensers that emit pheromones for a relatively long period and sprayable products that last for shorter periods and need to be reapplied. Isomate-CTT is a common codling moth pheromone dispenser that lasts for the entire growing season. Use approximately 150 to 200 dispensers per acre, with the lower rates recommended in orchards where mating disruption has been previously used or with very low population densities. Isomate-M100 (100 dispensers per acre) and Isomate Rosso (160 dispensers per acre) are Oriental fruit moth pheromone dispensers that last about 85 and 140 days, respectively. Under low population densities, it is possible to reduce OFM dispenser rates to approximately 75 percent of the full rate. Suterra Inc. makes a sprayable 32 pheromone product for the Oriental fruit moth, with residual activity of 4 to 5 weeks; hence, these products need to be reapplied at 4- to 5-week intervals. Timing of Applications: For the codling moth, place pheromone dispensers in the orchard before adults begin to fly in the spring. First emergence of adults usually begins during late bloom or petal fall of Delicious cultivars. Hence, dispensers should be hung by petal fall. For codling moth, best results are obtained when dispensers are hung in the upper third of the canopy. The Oriental fruit moth begins to emerge near green tip of Delicious cultivars, so for season-long control dispensers should be in the orchard by this time. However, if an insecticide effective against Oriental fruit moth is used at petal fall, it will control the first generation. It is possible to delay placement of Isomate-M100 until just before emergence of second- or third-generation adults (950 and 1850 DD after biofix, respectively). This delayed placement should prevent the need for a second application of Isomate M100 dispensers, which may otherwise be necessary on later maturing cultivars. If using sprayable pheromones for mating disruption, make the initial application when hand-applied dispensers are applied. Monitoring Insects: Checking fruit for larval damage is critical to determining the effectiveness of mating disruption and the need for rescue sprays. Monitoring adult populations of codling moth and Oriental fruit moth with pheromone traps is strongly recommended to provide baseline information on population density, to monitor the effectiveness of mating disruption, and to improve the timing of mating disruption and insecticide treatments. Good monitoring is an important part of achieving successful results. Effective pheromone mating disruption treatments will shut down trap catches of male moths. However, pheromone trap monitoring should not be used as the sole method of measuring efficacy. Also remember that mating disruption is species specific, so monitoring of other insect pests is also important. European Red Mite Management Several beneficial arthropods can help keep European red mite (ERM) populations below damaging levels. The most common in the Southeast are the phytoseiid mite (Amblyseius fallacis) and the a complex of generalist predators (e.g., lady beetles and lacewings). However, recent research in North Carolina suggests that neither of these predators overwinters to any significant degree within orchards, so they must be reestablished in orchards in the spring. Hence, practices that delay the buildup of ERM and enable predators to increase before mites become a problem will favor biological control. The two most effective practices are applying a delayed dormant oil spray and avoiding insecticides toxic to these predators. Monitoring Mite Populations: Use a regular monitoring program to follow the buildup of mite populations and to determine if and when supplemental applications of a miticide are necessary to avoid economic damage. Monitor each contiguous block of apples weekly beginning when adult mites first appear (which may vary from mid May to early July). Within each block, examine 5 leaves from each of 10 trees with a visor lens or hand lens. Rather than counting the total number of mites on each leaf, record the number of leaves infested with one or more mites, and estimate the mite density on a per-leaf basis from the table below. Determining the Need for Miticides: When mite populations reach a density of 5 to 10 mites per leaf (80 to 90 percent infested leaves) decide whether to use biological control or a miticide to prevent mites from increasing to higher densities. For biological control with Stethorus punctum to occur, the ratio should be 2.5 S. punctum to 1 ERM. S. punctum should be sampled by counting the number of adults and larvae observed during a timed 3- minute search around the periphery of mite-infested trees. S. punctum larvae must almost always be present if this predator is to control mites. Count the actual number of A. fallacis on sample leaves with a visor lens. If the ratio of A. fallacis to ERM is between 1 to 5 and 1 to 15, biological control is possible. If neither predator is present at sufficient levels for biological control to occur, and mite populations are between 5 to 10 mites per leaf, apply a miticide. In areas where Alternaria blotch is a problem on Delicious apples, biological control is usually not an option. In the presence of Alternaria blotch, mite populations must be maintained a very low levels to avoid high levels of Alternaria and premature defoliation. If preventive control measures are not used, a modified threshold level of 1-2 mites per leaf should dictate the need for miticides. Relationship between European red mite densities per leaf and percentage of mite-infested leaves. % Mite-Infested Leaves (>1 mite/leaf) Expected No. Mites per Leaf % Mite-Infested Leaves (>1 mite/leaf) Expected No. Mites per Leaf 40 45 50 55 60 65 0.7 0.9 1.1 1.3 1.6 2.0 70 75 80 85 90 95 2.6 3.4 4.7 6.8 11.4 26.4 33 Codling moth degree days (50oF lower base, 88oF upper base) at various daily maximum and minimum temperatures. Max 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 Min 20 0 1 1 2 2 3 3 4 5 5 6 7 8 9 9 10 11 12 13 14 15 15 22 0 1 1 2 2 3 3 4 6 6 6 7 8 9 10 10 11 12 13 14 15 15 24 0 1 1 2 2 3 4 4 6 6 7 7 8 9 10 11 11 12 13 14 15 16 26 0 1 1 2 2 3 4 4 6 6 7 7 8 9 10 11 12 12 13 14 15 16 28 0 1 1 2 2 3 4 4 6 6 7 8 8 9 10 11 12 13 14 15 15 16 30 0 1 1 2 2 3 4 5 6 6 7 8 9 10 10 11 12 13 14 15 16 16 32 0 1 1 2 3 3 4 5 6 6 7 8 9 10 11 11 12 13 14 15 16 17 34 0 1 1 2 3 3 4 5 6 7 7 8 9 10 11 12 13 14 14 15 16 17 36 0 1 1 2 3 4 4 5 6 7 8 8 9 10 11 12 13 14 15 16 17 17 38 0 1 1 2 3 4 4 5 6 7 8 9 10 11 11 12 13 14 15 16 17 18 40 0 1 2 2 3 4 5 6 6 7 8 9 10 11 12 13 14 15 16 17 17 18 42 0 1 2 2 3 4 5 6 7 7 8 9 10 11 12 13 14 15 16 17 18 19 44 0 1 2 3 3 4 5 6 7 8 9 10 11 12 13 14 15 15 16 17 18 19 46 0 1 2 3 4 5 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 48 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 20 50 1 2 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 52 2 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 54 - 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 56 - 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 58 - - 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 60 - - - 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 62 - - - - 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 64 - - - - - 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 66 - - - - - - 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 68 - - - - - - - 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 70 - - - - - - - - 18 19 20 21 22 23 24 25 26 27 28 29 30 31 72 - - - - - - - - - 20 21 22 23 24 25 26 27 28 29 30 31 32 74 - - - - - - - - - - 22 23 24 25 26 27 28 29 30 31 32 33 76 - - - - - - - - - - - 24 25 26 27 28 29 30 31 32 33 34 80 - - - - - - - - - - - - 26 27 28 29 30 31 32 33 34 35 Oriental fruit moth degree days (45oF lower base, 91oF upper base) at various daily maximum and minimum temperatures. Max 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 Min 20 1 1 2 2 3 4 4 5 6 7 8 9 9 10 12 12 13 14 15 16 17 17 18 19 22 1 1 2 2 3 4 4 6 7 7 8 9 10 11 12 12 13 14 15 16 17 18 18 19 24 1 2 2 2 4 4 5 6 7 7 8 10 10 11 12 12 14 15 15 16 18 18 19 20 26 1 2 2 3 4 5 5 6 7 7 8 10 10 11 12 13 14 15 16 16 18 18 19 20 28 1 2 3 3 4 5 5 6 7 8 9 10 10 11 13 13 14 15 16 17 18 19 20 20 30 1 2 3 3 4 5 5 6 7 8 9 10 10 12 13 13 15 16 16 17 19 19 20 21 32 1 2 3 3 4 5 6 6 8 8 9 10 11 12 13 14 15 16 17 18 19 19 20 21 34 1 2 3 3 4 6 6 7 8 8 10 11 11 12 14 14 15 17 17 18 19 20 21 21 36 1 2 3 3 5 6 6 7 8 9 10 11 11 13 14 14 16 17 18 19 19 20 21 22 38 1 2 3 4 5 6 6 7 9 9 10 11 12 13 14 15 16 17 18 19 20 21 21 22 40 1 2 3 4 5 6 6 8 9 9 10 11 12 13 15 15 16 18 18 19 20 21 22 23 42 1 3 4 4 6 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 44 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 46 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 48 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 50 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 52 - 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 54 - - 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 56 - - - 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 58 - - - - 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 60 - - - - - 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 62 - - - - - - 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 64 - - - - - - - 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 66 - - - - - - - - 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 35 68 - - - - - - - - - 23 24 25 26 27 28 29 30 31 32 33 34 35 36 36 70 - - - - - - - - - - 25 26 27 28 29 30 31 32 33 34 35 36 37 37 72 - - - - - - - - - - - 27 28 29 30 31 32 33 34 35 36 37 38 38 74 - - - - - - - - - - - - 29 30 31 32 33 34 35 36 37 38 39 39 78 - - - - - - - - - - - - - 31 32 33 34 35 36 37 38 39 40 40 80 - - - - - - - - - - - - - - 33 34 35 36 37 38 39 40 41 41 34 Pesticide Resistance Management General Considerations Pesticide resistance is a shift in the genetics of a pest population that allows individuals within a previously susceptible population to survive. Resistant pest populations have inherited traits that reduce their susceptibility to individual pesticides or groups of pesticides. Resistance develops in all agricultural pest groups–insects, mites, fungi, bacteria, nematodes, and weeds. Pesticide-resistant individuals are initially quite rare in pest populations. However, when a new pesticide is first used, a very low number of individual pests never previously exposed to the novel chemistry can be expected to be resistant. The frequency of resistant genes to novel chemistries varies tremendously, but history makes it clear that resistant individuals should be expected to be present in all pest groups. By the nature of the process, resistance most often develops to pesticides that are initially very effective and frequently used. Pesticide resistance management is an effort to slow or prevent the development of resistance. It relies on pest management and pesticide-use strategies to prolong the effective life of pesticides. Resistance management is difficult, especially in high-value crops like fruit, where high quality standards and limited numbers of registered pesticides make the task more challenging. Managing resistance requires an understanding of the factors that influence its development. Selection is the process of pesticide-induced selection for resistance. With regular pesticide use, those rare individuals that are naturally resistant survive and reproduce more successfully than their susceptible peers. Resistance frequency refers to the proportion of a pest population that is resistant. Cross resistance refers to a type of resistance in which a pest population develops resistance to more than one pesticide within a chemical family (e.g., organophosphate insecticides, EBDC fungicides, etc.). Multiple resistance involves multiple, independent resistance mechanisms, which often lead to resistance to chemicals from different families (i.e., organophosphate and carbamate insecticides, dodine and DMI fungicides). Resistance stability is a key factor in managing resistance. Stability is an estimate of how well resistance persists in a pest population once the pesticide is no longer used. The rate of reversion to a susceptible state varies enormously. But when pesticide use ceases, selective pressure for resistance is removed, and over time resistance will often be reduced. Resistance stability estimates may allow limited use of resistance-prone compounds. It is important to emphasize that control failures do not confirm resistance. Other factors (poor timing, sprayer calibration or coverage, wash-off, high pH in spray tank water, inappropriate materials, etc.) should be eliminated as causes for control failures before resistance is seriously considered. Factors influencing the development of resistance can be grouped into biological and management categories. Biological factors include pest reproductive rate, mobility of the pest species into and out of untreated areas, and genetic factors such as number of resistance mechanisms, resistance frequency and intensity, and resistance stability. Management factors that influence resistance development include how materials are applied, how often they are used, how long they persist in the field, treatment thresholds, and strategies for using available pesticides. Resistance management efforts study specific pest-pesticide interactions and focus on practical strategies that growers can implement. Pest management is practical and works in concert with pesticide-use strategies to lessen resistance selection by facilitating prudent, as-needed pesticide use. Pesticide-use strategies work best when implemented as a new pesticide comes into commerce. Pesticide manufacturers, IPM scientists, and growers have come to recognize that using resistance management from the beginning works best. Collecting baseline susceptibilities, defining probable resistance problems beforehand, and proposing pesticide-use strategies to forestall resistance development are the province of manufacturers and IPM scientists. Biologically and economically sound resistance management plans offered pre-sale give growers the best hope for managing resistance. Pesticide-use strategies are often grouped as follows: (1) management by moderation, (2) rotation and mixtures, and (3) saturation. Moderation means limiting the use of a pesticide. Moderation is employed in concert with IPM practices, such as using treatment thresholds, spraying only specific pest generations or growth stages, maintaining unsprayed wild host reservoirs to act as refuges for genetically susceptible individuals, using pesticides with shorter residual or lower toxicity to important beneficial populations, etc. Moderation should be used to the fullest extent that will provide commercially acceptable control. Rotation, and in some cases mixtures, are the bulwarks of pesticide-use strategies since an individual pest is less likely to be resistant to two or more differing classes of toxins. In theory, most individual pests resistant to one pesticide will be killed when exposed to a different class of toxin. Rotations depend on having effective, labeled materials with different modes of action. Material cost is a key practical consideration that favors rotation. Mixtures of fungicides have been used successfully to combat disease resistance, although cost lessens the attractiveness of this approach. Mixtures of insecticides and miticides have typically performed poorly. Rotation is seen as the desired approach for insecticides, miticides, and some fungicides. Saturation, the use of higher pesticide rates to control resistant individuals, is the least attractive resistance management approach, although it has been used to manage resistance to DMI fungicides. Saturation is generally a last resort, when there are no other effective, labeled alternatives. In this scenario, higher rates will often provide control for a time, although at greater cost. Synergists, chemicals that increase the toxicity of pesticides, have sometimes been effective in boosting the efficacy of resistance-prone pesticides. As with simple rate increases, saturation with synergists typically provides only short-term benefits. 35 Insecticide Resistance Management Strategies In the southeastern United States, the tufted apple bud moth, codling moth, rosy apple aphid, and European red mite have developed resistance to one or more pesticides. Although codling moth and mite resistance are not widespread in the Southeast, problems in other parts of the U.S. indicate the importance of employing sound pesticide use patterns to prevent resistance development in this region. Tufted Apple Bud Moth The tufted apple bud moth has developed resistance to organophosphate insecticides, most notably Guthion and Imidan. However, Intrepid, SpinTor, Avaunt, Rimon, and Danitol are effective alternatives. Along with Bacillus thuringiensis products, these products provide growers with a diversity of options with different modes of action to manage TABM. The recommended strategy is this: Do not use the same insecticide (or insecticides with the same mode of action) against successive generations. For example, if Intrepid is used against the first generation in year 1, then Avaunt, Rimon or SpinTor should be used against the second generation. Against the first generation in year 2, do not use the same insecticide used to control the second generation in year 1. When selecting an insecticide, one should consider other insects that also may need to be controlled. Rosy Apple Aphid The rosy apple aphid has developed widespread resistance to Lorsban, and control failures with Thiodan, Asana, Ambush, Diazinon, and Dimethoate have become more common in recent years. Among the neonicotinoid insecticides, suspected failure with Actara has been observed. However, all the neonicotinoids (i.e., Actara, Assail, Calypso, Clutch, and Provado) have a similar mode of action and should be considered the same material for rotation purposes. The two best times to control rosy apple aphid on apple are 1) tight cluster to pink and 2) petal fall. Do not apply any insecticide more than once during this time frame, and if possible do not use the insecticide used for rosy apple aphid control more than once during the period when the aphids may occur in apple orchards (through the third or fourth cover spray). European Red Mite Avoiding unnecessary miticide applications is the most effective strategy for minimizing the potential for resistance development. A delayed dormant oil application is highly recommended to suppress overwintering populations of European red mite and to improve the potential for biological control to maintain mite populations below damaging levels. On Delicious cultivars, which are susceptible to alternaria blotch and where preventive control or low threshold levels are recommended for control of European red mite, there is a high potential for the development of resistant populations. To reduce this potential, in addition to a delayed dormant oil application, only one of the following options should be used in a given year, and the same option should not be used in two consecutive years. Preventive Strategies Curative Strategies • Agri-Mek + oil at petal fall • Apollo or Savey at first or second cover • Zeal at first or second cover • Envidor at first or second cover • Acramite at 2 mites per leaf • Nexter at 2 mites per leaf Resistance Management Strategies for Plant Pathogens Resistance of plant pathogens to pesticides has become widespread over the past 25 years as site-specific (systemic) chemicals have been developed and used on many crops and against many pathogens. The broad spectrum protectants (such as captan and mancozeb) that were used previously had multiple sites of activity in the target pathogens, greatly reducing the likelihood of resistance development. Resistance has become a problem in the U.S. in only three pathogens that affect apples during the growing season: Venturia inaequalis, cause of apple scab; Erwinia amylovora, cause of fire blight; and Pseudomonas syringae pv. papulans, cause of blister spot. Resistance of V. inaequalis to dodine (Syllit, initially sold as Cyprex) was first reported in New York in 1969. It has subsequently been reported in several states in the Northeast and Midwest but has not been found in orchards in the Southeast. Resistance of V. inaequalis to the benzimidazole fungicides [benomyl (Benlate) and thiophanate methyl (Topsin M)] was reported shortly after their introduction in 1971 and became widespread in the eastern U.S., including the Southeast, in the mid-1970s. As a consequence they are no longer recommended for apple scab control in the Southeast. The ergosterol biosynthesis inhibiting fungicides [fenarimol (Rubigan), myclobutanil (Nova), triflumazole (Procure)] were first introduced in the late 1980s, and reduced sensitivity of V. inaequalis has been reported or suspected in a number of orchards in the Northeast and Midwest but is not widespread. Resistance of the fire blight bacterium, E. amylovora, to streptomycin (Agri-mycin 17, Streptrol) is widespread in several states but has not been reported in the Southeast. Resistance of P. syringae pv. papulans has been confirmed in an orchard in Tennessee. To avoid resistance development, minimize the use of fungicides and bactericides in which resistance is likely to develop. Additionally, combine site-specific fungicides with protectant fungicides that have broad spectrum activity. Limit dodine applications to two to three per year. In areas where dodine resistance first became a problem, it was often used 10 to 12 times throughout the growing season. Similarly, limit streptomycin use for fire blight control to two to four times a year. Make applications only during times favorable for infection. These periods are characterized by open blossoms, dew or rainfall 36 greater than 0.01 inch, an average daily temperature of 60º F or greater, and the accumulation of at least 198 degree-hours greater than 65º F since the first blossoms opened. Use the ergosterol biosynthesis inhibiting fungicides only in combination with broad spectrum protectants, such as captan or EBDC fungicides. Avoid post symptom applications of site-specific fungicides, such as dodine and the DMI fungicides, because this sets up an ideal situation for selection of resistant strains. Good orchard sanitation practices to maintain pathogen populations at low levels is also an important component of a resistance management program. Managing Weeds and Preventing the Development of Herbicide Resistance Although weed resistance to herbicides is not discussed as often as resistance in insects and pathogens, cases of weed resistance to herbicides do exist. For example, pigweed and goosegrass are resistant to dinitroanaline herbicides (Prowl and Surflan), and Johnsongrass is resistant to carboxylase herbicides (Fusilade DX). Resistance may not be detected for several years because these resistant weeds produce seed, and then subsequent generations must establish. Two factors that contribute to the development of herbicide-resistant weeds are applying herbicides multiple times during the year and using herbicides that have the same mechanism of control for several consecutive growing seasons. Because apples are a perennial crop and have limited herbicide options, techniques like crop rotation and mechanical cultivation to prevent resistance in annual crops are not feasible. However, some of the following strategies can help prevent resistance from developing: 1. Use herbicides ONLY when necessary. 2. Rotate herbicides with different modes of action. For example, do not use simazine (Princep, Simazine) continuously. Consider other preemergence broadleaf herbicides. Also avoid making more than two applications of the same herbicide in the same year. 3. Scout orchards regularly to identify weeds. Respond quickly to changes in weed population by controlling weeds before they spread through the entire orchard. 4. Use nonselective postemergence herbicides in your weed management program. Effect of pH on Pesticide Activity Although the pH of spray water does not directly affect resistance development, it can affect the activity of some pesticides. In most instances the label warns of this effect. These include dimethoate, phosmet, malathion, azinphosmethyl, formetanate, ethephon, NAA, and possibly others. When these materials, except NAA, are exposed to a pH above 7.5, they undergo hydrolysis and break down to products that are either less effective or not effective. Excessively acidic conditions may limit uptake of NAA and, therefore, its effectiveness. The actual rate of breakdown depends on solubility and temperature and the total quantity broken down during a given period. For example, captan is hydrolyzed very quickly at alkaline pHs, but because it is very insoluble, the impact of pH is negligible unless captan is allowed to stand around for a week or more. This is also true for chlorothalonil. Hydrolysis increases with increased temperature. If the time in the spray tank is limited by applying pesticides immediately, then the quantitative amount broken down is limited. Additives to the spray tank can also be a factor. Calcium chloride, especially when concentrated in the tank and applied in a low volume spray, can increase the pH. The greater the concentration, the greater the alkalinity. The manufacturing process for calcium chloride leaves residues of free lime (calcium hydroxide). The greater the purity of the calcium chloride, the lower the content of calcium hydroxide and the lower the effect on pH. The water source can be a factor. Although most wells, streams, and rivers in the southeastern growing region are mildly acidic (6.7 plus or minus 0.2) there are exceptions; therefore, check pH a few times before regular use. Ponds are more likely to be alkaline, especially those high in algae and other organisms. These ponds undergo diurnal pH changes as result of dissolved carbon dioxide. Levels greater than 10 have been observed. Alkalinity contributed by CO2 is weakly buffered and readily changed by acidifying agents. Although not pH-related, some pesticides can be affected by other contaminants in the water. For example, fenbuconazole, not labeled on apples, is greatly reduced in effectiveness by suspended particulates. Still other compounds like 2,4-D and azoxystrobilurin can be very difficult to wash out of the tank and can have a deleterious effect on apples at very low concentrations. 37 Orchard Floor Management The best strategy for managing the orchard floor is to use a noncompetitive grass alley with a vegetation-free strip in the tree row. The vegetation-free strip can be established and maintained with herbicides as described in this section. The permanent grass sod between the tree rows will minimize soil erosion, increase soil aeration and permeability, and support equipment movement through the orchard during wet weather. The vegetation-free strip eliminates competition for water and nutrients, minimizes tree damage or loss from voles during the dormant season, and provides some radiant heat from the soil surface should a spring frost or freeze occur. Herbicides are directed at the soil and weeds underneath the tree. The vegetation-free strip method is superior to all other orchard floor management options. Vegetation under the tree competes for nutrients and water, resulting in reduced growth, yield, and size of fruit. Another option is the use of organic mulches in the tree row. Examples of mulching materials include straw, wood chips, and grass residue from mowing. These mulches will suppress weed emergence, but weed removal by some means will still be necessary. Mulches can improve the water-holding capacity of some soils. However, there are several concerns regarding the use of organic mulches. The most significant problem is that mulches create an ideal habitat for voles. Also, additional nitrogen may be needed to support the microorganisms that drive decomposition of organic mulches. In poorly drained or water-logged soils, organic mulches increase the likelihood of phytophthora root rot. Mulches can be expensive and difficult to obtain. Synthetic mulches made from polyethylene, polypropylene, or polyester can be placed in the tree row around the base of the trunk or as a narrow strip down the row. Some newer synthetics allow water and air to pass through the mulch. Herbicide Considerations To ensure proper herbicide use, always read the manufacturer*s label before application. All statements on the manufacturer’s label take precedence over any recommendations in this publication. It is important that herbicide application equipment be properly calibrated to ensure that herbicides are applied at the correct rate. For questions about calibrating your sprayer, contact your county’s Cooperative Extension agent. Remember that herbicides are applied as a directed spray along each side of the tree row. Flat fan nozzles are most widely used for applying herbicides. They provide excellent spray coverage of weeds and come in several sizes with capabilities to apply a range of spray volumes. Some manufacturers make flat fan nozzles that minimize spray drift, allowing low pressure spraying. Investing in such spray nozzles decreases the likelihood of off-target herbicide movement. It is advisable to apply white latex paint to the bottom 2 to 3 feet of the tree trunk of newly planted trees before applying herbicides. Painting the tree trunks reduces the potential for winter as well as herbicide injury, especially from postemergence herbicides. Dip a car wash mitt (wear rubber gloves underneath the mitt) in paint and rub up and down the tree trunk until it is completely painted. Several herbicides are registered for use in apple orchards. Some are preemergence herbicides that control weeds that have not emerged, and others are postemergence herbicides that control emerged weeds. Preemergence herbicides control germinating weed seeds but usually do not give acceptable control of emerged weeds. Rainfall is needed to properly activate preemergence herbicides. Rainfall within 7 to 14 days after application activates most herbicides; however, best control occurs when water (rain or irrigation) is added within a few days of application. The desired amount of time for rainfall after application varies by herbicide. Refer to the manufacturer’s label for specific information. Postemergence herbicides control emerged weeds and are most effective when applied to actively growing weeds. Weeds under stress from drought or mowing may not be adequately controlled by postemergence herbicides. If weeds are stressed from drought, delay herbicide application until after adequate rainfall when weeds are no longer wilted. If weeds have been mowed, wait several days to allow regrowth before applying herbicides. Symptoms of herbicide activity may not be noticeable for up to 14 days after application of glyphosate, sethoxydim, clethodim, or fluazifop (Roundup, Poast, Select, or Fusilade DX, respectively). Effects of glufosinate, paraquat, and 2,4-D (Rely, Gramoxone Max, and Orchard Master, respectively) are noticeable in 1 to 3 days. Some postemergence herbicides require the addition of a surfactant or crop oil to improve herbicide activity. Remember, surfactants and crop oil differ from one another and may not be interchangeable. Herbicide Application Timing The goal of an effective weed management program is to eliminate weed competition the first 6 to 8 weeks after bud swell and keep the area under the trees weed-free through harvest. Timing of preemergence (PRE) herbicide application is important in accomplishing this goal. It has been typical to make a single PRE herbicide application in the spring followed by postemergence (POST) herbicide applications in the summer as needed. However, it can be difficult to spray underneath limbs loaded with fruit in mid and late summer. With appropriate PRE herbicide timing, POST herbicide applications in mid and late summer can be avoided. Listed below are several PRE herbicide timing options. 1. Fall/Spring Split. One approach is to apply a PRE herbicide with a nonselective burn-down herbicide (glyphosate or paraquat) in the fall after harvest (November). The fall application will generally provide PRE control into the early summer. When fall PRE treatment breaks and emerging weeds get 2 to 3 inches tall, another PRE herbicide application with a burndown herbicide should be applied. Fall herbicide application may be helpful in managing voles. In areas where erosion is a concern this option may not be acceptable. 2. Delayed Preemergence. This approach requires a burndown herbicide application in March. The burndown herbicide eliminates winter annual weeds until summer annual weeds emerge in early to mid May. Once summer annual weeds get 2 to 3 inches, apply a burndown with a PRE herbicide. 38 Postemergence herbicides may be necessary to control escaped weeds or certain problem weeds like Bermudagrass, Johnsongrass, and mugwort. It is important to scout orchards regularly to determine weed species present. Scouting allows growers to recognize the need to control escaped weeds with a timely herbicide application and for early identification of difficult-to-control weeds. Early identification of problem weeds can prevent them from becoming established in the orchard. If problem weeds are noticed for the first time in an orchard, they need to be removed before they produce seed. This can be done by hand or with a spot treatment with a nonselective postemergence herbicide like glyphosate, paraquat, or glufosinate (Roundup WeatherMax, Gramoxone Max, or Rely, respectively). Scouting also gives growers an opportunity to recognize poorly controlled weeds so their weed management program can be adjusted. Another aspect growers should consider is the potential for infestations of weeds from around the border of the orchard. Weeds in these areas produce seeds that will find their way into the orchard. Chemical Mowing Some herbicides can be used at sublethal doses to suppress orchard floor vegetation. Timing and rate will vary with the vegetation present. Generally, tall fescue can be used as the guiding species, because it is a major component in most orchards. Optimum timing for suppression is when tall fescue has 3 to 6 inches of new growth in the spring. The following herbicides and rates are suggested: Roundup WeatherMax at 4 fluid ounces, generic glysophate products at 5 to 6 fluid ounces, and Poast 1.5E at 1 to 1.25 pints per acre. Chemical suppression of grasses should be done only to healthy, well-established sod. Refer to product labels for details. Weed Management in Newly Planted Trees Eliminating weed competition is an important part of minimizing posttransplant stress to newly planted trees. Research has shown that weed competition can reduce tree growth and development by 50 percent. Newly planted orchards are not nearly as competitive with weeds as older, established orchards. Young trees do not have well-developed limbs to shade the soil surface in late summer, which minimizes the competitiveness of late summer weeds. In general, preemergence herbicides registered for use after transplanting provide effective preemergence control of annual grasses and small-seeded broadleaf weeds. Painting the lower 18 inches of the tree trunk with a white latex paint is highly recommended. The paint provides a barrier to herbicides, protecting tender, green bark from serous injury. Apple Pollination, Honey Bees, and Pesticides Most apple varieties are self-incompatible and require cross-pollination with a suitable pollinizer variety to obtain good fruit set. Honey bees and other native bees are the primary pollinators for apples. All bees are susceptible to insecticides and need to be protected during bloom and at other times. Most insecticide labels include a warning: “This product is highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops if bees are visiting the treatment area.” Any apiary within 2 ½ miles of the orchard is at risk from insecticide applications. Bees are highly attracted to flowers in the ground cover. Before applying insecticides, reduce dandelion, clover, and other ground cover flowers by mowing or herbicide. The following recommendations will help to minimize bee kills: ! Read and obey warning statements on pesticide labels regarding honey bees. ! Select the safest available formulation. Emulsifiable concentrate (EC) formulations usually have shorter residual toxicity than wettable powder (WP) formulations. ! Insecticides applied during unusually low temperatures will remain toxic to bees for a much longer time compared to normally warm weather. ! Avoid applying insecticides to blooming cover crops, and avoid insecticide drift to nearby plants in bloom. ! If an insecticide hazardous to bees must be used, apply it in the early evening to minimize hazard to bees. Always check to make sure bees are not foraging when pesticides are applied. ! Never apply a pesticide directly over a beehive. Notify neighboring beekeepers when applying pesticides toxic to bees. ! Dispose of all unused pesticides safely so that pesticides do not end up in watering sources used by bees. 39 Soil and Plant Analysis Guidelines for Southeastern Apple Production Routine nutrient analysis of soil and plant leaf tissue should be an integral part of any orchard management plan. Soils used for apple production in the Southeast vary greatly, especially in the mountains. Other factors, such as weather and crop history, can affect the trees’ nutrient status. The only way to be sure your trees are being fertilized efficiently and properly is by using soil and plant analysis. Proper use of these tools will help ensure sustained yields while preventing unneeded fertilizer application. Ideally, both soil and plant sampling should be done every other year. On sites that have a history of nutritional problems, such as bitter pit, sampling every year may be needed. A soil analysis estimates the ability of the soil to supply a particular nutrient. Plant tissue analysis measures the current nutrient status of the tree. Potential nutritional problems can often be detected before visual deficiency symptoms appear. By using both soil and plant analysis together, a fertility program can be custom designed for your orchard. The general idea is to give each block of trees what is needed for growth and apple production, but not to apply nutrients that can be supplied by the soil in adequate amounts. Sampling for Soil Analysis A soil analysis report is only as good as the sample it represents. For soil analysis to be meaningful, the sample must be representative of the soils in the orchard. Due to soil variability, each sample should represent no more than a 5-acre block of similar terrain and soil type. Trees in the block should be of the same age, rootstock, and variety. A good sample consists of up to 20 sub-samples (cores). These should be throughly mixed in a clean bucket before filling the soil sample box. Samples should be divided into two depths: 0 to 6 inches and 6 to 12 inches. This is easiest when using a soil sampling tube. Sampling for Plant Analysis Plant sampling needs to be carried out in a manner similar to soil sampling. For best results, plant sampling areas should be the same as selected for soil sampling. All trees should be the same age, variety, and rootstock. To make full use of published critical nutrient levels, and thus obtain the best information, routine plant samples should be taken mid June to mid July, with earlier sampling at lower elevations. Sample mid-shoot of this season’s growth from the upper third of the tree. Collect a total of 40 leaves taken from at least ten trees selected randomly from the sample area. Using Soil and Plant Analysis as an Aid in Troubleshooting Soil and plant analysis can be invaluable in properly identifying and correcting nutrient deficiencies. In this case, samples are collected over a smaller area that represents the problem. If possible, it is advisable to collect samples from “good” areas adjacent to the problem areas. Both soil and plant samples need to be collected. Interpretation of Soil and Tissue Analysis Soil and plant analysis laboratories differ in analytical procedures and report format. Southeastern laboratories, both private and public, use at least two different soil-extracting solutions. A single soil sample processed by these two methods could yield very different results, especially for phosphorus. Also, different laboratories report the results in different units – some use an index system while others report parts per million or pounds per acre. A given laboratory takes these factors into account when giving fertility recommendations. In other words, their recommendations are calibrated to their methods. Thus recommendations from different labs’ soil analyses should be similar. However, the differences in reporting units make it difficult to compare results from different laboratories. To track the progress of a fertility program over the life of the trees, it is best to use either one laboratory or pick laboratories with the same methods and reporting units. Even though tissue analysis methods are more uniform, reporting units still differ between laboratories, making it difficult to track trends over time. Special Considerations for Calcium and Boron Calcium and boron deficiency can result in fruit being culled due to bitter pit (calcium deficiency) or cork spot (boron deficiency). In some years, the percentage of cull fruit exhibiting bitter pit or cork spot can be quite high. These nutrients can be difficult to supply in needed quantities, especially in older trees and large-f |
OCLC number | 66380622 |