Integrated orchard management guide for commercial apples in the Southeast.

              2009 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 TennesseePoison Control Centers and Emergency Facilities
PESTICIDE POISONING B 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 carefacility. 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 an
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 2009 Integrated Orchard Management Guide for Commercial Apples in the Southeast
Table of Contents
Pest and Orchard Management Program.........................................................2
Tree Row Volume: A Model for Determining Spray Volume......................30
IPM Practices for Selected Pests...................................................................32
Pesticide Resistance Management................................................................37
Effect of pH on Pesticide Activity................................................................39
Orchard Floor Management..........................................................................40
Apple Pollination, Honey Bees, and Pesticides............................................41
Soil and Plant Analysis Guidelines for Southeastern Apple Production.......42
Fertility Management Recommendations for Apples....................................43
Relative Effectiveness of Fungicides............................................................44
Relative Effectiveness of Insecticides and Miticides....................................47
Toxicity of Pesticides to Beneficial Arthropods...........................................49
Weed Response to Preemergence Herbicides...............................................50
Weed Response to Postemergence Herbicides..............................................51
Fungicides and Bactericides..........................................................................53
Insecticides and Miticides.............................................................................56
Herbicides.....................................................................................................62
Growth-Regulating Chemicals......................................................................66
Vertebrate Management................................................................................73
Pesticide Safety.............................................................................................79
EPA Registration Numbers of Various Materials.........................................80
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, N.C. 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
Soils and Nutrition Ron Gehl
Contributors
Alabama
South Carolina
Bobby Boozer
Ed Sikora
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
Ron Gehl
Steve McArtney
Wayne Mitchem
Mike Parker
Turner Sutton
David Tarpy
Steve Toth
Jim Walgenbach
Soil Science
Horticulture
Horticulture
Horticulture
Plant Pathology
Apiculture
Safety
Entomology
2
Pest and Orchard Management Program
DORMANT
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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 43) 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 66) 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 66) 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 66) 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. 3
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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 leaf spot.
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. 4
SILVER TIP
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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 or
80W or
80WDG
++++
++++
++++
++++
—
—
4 lb
2 qt
2.5 lb
2.5 lb
96
96
24
24
0
0
0
0
An important spray for black rot control in Georgia. Warning: Captan will cause injury when used with or too close to oil applications.
Fungicides
Ridomil Gold EC or WSP
++++
See label.
12
1
Aliette 80WDG or 80 WSP
++++
⅝ to 1½ lb
2 to 5 lb
12
14
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.
Control crown rot
(collar rot).
Phosphite fungicides
++++
See label.
Phosphite fungicides (i.e. Prophyt, Agri-Fos, and others) are registered for crown rot control and have activity similar to Aliette. See labels for use instructions and precautions.
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. 5
GREEN TIP TO ½-INCH GREEN
Rate Per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Disease Management
Fungicides
Syllit 65W
+++++
½ to ¾ lb
2 to 3 lb
48
7
Vangard 75WG
+++++
1.25 oz
5 oz
12
72
Vangard 75WG
+ mancozeb
80WP or
75DF 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
Vangard tends to be most active at cool temperatures.
Scala SC
+++++
1.75 to 2.5 oz
7 to 10 oz
12
72
Scala SC
+ mancozeb
80WP or
75DF 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
Scala SC is not compatible with captan.
Sovran 50WG
+++++
1 to 1.6 oz
4 to 6.4 oz
12
30
Flint 50WG
+++++
—
2 to 2.5 oz
12
14
Control scab.
See discussion in Fungicides and Bactericides (page 53) for information on postinfection control program.
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.6
GREEN TIP TO ½-INCH GREEN (continued)
Rate Per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Rubigan 1E
+ captan 50WP or
80W or
80WDG
or
+ mancozeb
80WP or
75DF or
F4
or
+ Polyram 80DF
+++++
+++++
+++++
+++++
+++++
3 to 4 oz
¾ lb
0.47 lb
0.47 lb
¾ lb
¾ lb
0.6 qt
¾ lb
8 to 12 oz
3 lb
1.88 lb
1.88 lb
3 lb
3 lb
2.4 qt
3 lb
96
24
24
24
24
24
24
30
0
0
77
77
77
77
Rally 40W
+ captan 50W or
80W or
80WDG
or
+ mancozeb
80W or
75DF or
F4
or
+ Polyram 80DF
+++++
+++++
+++++
+++++
+++++
1¼ to 2 oz
¾ lb
0.47 lb
0.47 lb
¾ lb
¾ lb
0.6 qt
¾ lb
5 to 10 oz
3 lb
1.88 lb
1.88 lb
3 lb
3 lb
2.4 qt
3 lb
96
24
24
24
24
24
24
14
0
0
77
77
77
77
Control scab (continued).
Procure 50WS
+ captan 50W
80W or
80WDG
or
+ mancozeb
80W or
75DF or
F4
or
+ Polyram 80W
+++++
+++++
+++++
+++++
+++++
1 to 2 oz
¾ lb
0.47 lb
0.47 lb
¾ lb
¾ lb
0.6 qt
¾ lb
4 to 8 oz
3 lb
1.88 lb
1.88 lb
3 lb
3 lb
2.4 qt
3 lb
96
24
24
24
24
24
24
14
0
0
77
77
77
77
Do not use captan within 2 weeks of an oil spray.
Although resistance of the apple scab fungus to the EBI fungicides Rally, Rubigan, Indar, 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 an EBI fungicide, but it needs to be combined with a full rate of captan or captan + mancozeb or metiram to ensure scab control. An EBI 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.
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.7
Rate Per2
Goals
Options
Relative1 Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry Interval (hours)
Preharv. Interval (days)
Comments
Control scab (continued).
Indar 75WSP
+ captan 50W
80W or
80WDG
or
+ mancozeb
80W or
75DF or
F4
or
+ Polyram 80W
+++++
+++++
+++++
+++++
+++++
0.67 oz
¾ lb
0.47 lb
0.47 lb
¾ lb
¾ lb
0.6 qt
¾ lb
2.67 oz
3 lb
1.88 lb
1.88 lb
3 lb
3 lb
2.4 qt
3 lb
96
24
24
24
24
24
24
14
14
14
77
77
77
77
Inspire Super MP
+ Vangard WG
+++++
1.0 fl oz
1.0 oz
4.0 fl oz
4.0 oz
12
72
An active ingredient in Inspire Super MP is the EBI fungicide difenconazole. Consequently in orchards where EBI resistance is suspected Inspire Super MP + Vangard WG should always be combined with mancozeb or metiram.
Insect Management
Control scales and reduce overwintering European red mite and rosy apple aphid eggs.
Insecticides
Oil
+++++
2 gal
8 gal
12
0
Use either a superior-type or highly refined summer oil applied dilute. 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.
Improve scale and rosy apple aphid control.
Oil +
Lorsban 4E
or
Esteem 35WP
or
Diazinon 50WP
++++
+++++
++++
2 gal
½ to 1 pt
—
1.0 lb
8 gal
2 to 4 pt
4 to 5 oz
4 lb
12
96
12
24
0
DD
45
21
An insecticide with oil may be added at this time in orchards experiencing problems with scales or climbing cutworms. This option is recommended in orchards that experienced scale problems the previous year. 8
GREEN TIP TO ½-INCH GREEN (continued)
Rate Per2
Goals
Options
Relative1 Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry Interval (hours)
Preharv. Interval (days)
Comments
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 32) for monitoring information.
Mating disruption for OFM and codling moth.
Pheromones
Isomate CM/OFM TT
CheckMate CM/OFM
+++++
++++
Now is the time to begin erecting pheromone dispensers for mating disruption. Combination dispensers that contain both OFM and codling moth pheromone are recommended. Hanging of dispensers in trees should be complete by petal fall. See section on “Mating Disruption” in IPM Practices for Selected Pests (page 34).
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
TIGHT CLUSTER TO PINK
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Disease Management
Control scab.
Fungicides:
Same as used in green-tip spray.
If two sprays of Sovran, Pristine, or Flint were used, switch to a nonstrobilurin fungicide. Syllit, Scala, and Vangard are most effectively used in the first two sprays of the season.
Control powdery mildew.
Fungicides
Rally 40W
Rubigan EC
Bayleton 50DF
Procure 50WS
Indar 75WSP
+++++
++++
++++
+++++
+++++
1¼ to 2 oz
3 to 4 oz
½ to 2 oz
1 to 2 oz
0.67 oz
5 to 10 oz
8 to 12 oz
2 to 8 oz
4 to 8 oz
2.67 oz
24
12
12
12
12
14
30
45
14
14
These are the most important sprays for the control of powdery mildew.
Control cedar apple rust and quince rust.
Fungicides
Rally 40W
Rubigan 1EC
Procure 50WS
Indar 75WSP
Bayleton 50DF
mancozeb 80W or
75DF or
F4
Polyram 80W
Ferbam Granuflo
+++++
+++++
+++++
+++++
+++++
+++++
+++++
+++++
+++++
++++
1¼ to 2 oz
3 to 4 oz
1 to 2 oz
0.67 oz
½ to 2 oz
¾ lb
¾ lb
0.6 qt
¾ lb
½ lb
5 to 10 oz
8 to 12 oz
4 to 8 oz
2.67 oz
2 to 8 oz
3 lb
3 lb
2.4 qt
3 lb
2 lb
24
12
12
12
12
24
24
24
24
24
14
30
14
14
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 or
80 W or
80WDG
++++
++++
++++
++++
1½ to 2 lb
¾ to 1 qt
0.94 to 1.26 lb
0.94 to 1.26 lb
6 to 8 lb
3 to 4 qt
3.77 to 5 lb
3.77 to 5 lb
96
96
24
24
0
0
0
0
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 32) for information on monitoring programs. 10
TIGHT CLUSTER TO PINK (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv
Interval
(days)
Comments
Insect Management
Control rosy apple aphid.
Insecticides
Actara 25WDG
Assail 30SG
Calypso 4F
Thionex 50WP
Diazinon 50W
Danitol 2.4EC
+++++
+++++
+++++
+++
+++
++++
��
—
—
⅔ qt
1 lb
2.6 to 4.3 oz
4.5 oz
2.5 to 4 oz
2 to 4 oz
2⅔ qt
4 lb
10.6 to 21.3 oz
12
12
12
24
24
24
35
7
30
21
21
14
Pink stage is the best time to control rosy apple aphid. Caution: Rosy apple aphid resistance to Thiodan, Diazinon, and Danitol has been observed in some orchards. See Rosy Apple Aphid resistance section (page 38).
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.11
BLOOM
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Cultural Management
Loosen bags on leaders to acclimate for 2 to 3 days; then remove bags from leaders and spray with Promalin or Perlan.
Leader bags must be removed when new lateral growth is 1” to 3” long.
*****
See Growth-Regulating Chemicals section (page 66) 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
+++
+++
0.5 to 1.0 pt
1 to 2 pt
12
4
None
See Growth-Regulating Chemicals section (page 66). 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. Use on nonbearing trees only.
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 66).
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. 12
BLOOM (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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 Pesticide Resistance Management section (page 37) 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
Isomate CM/OFM TT
CheckMate CM-XL 1000
++++
++++
++++
(# dispensers)
200/acre
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 will be necessary under moderate to high population densities. See section on IPM Practices for Selected Pests (page 32).
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. 13
PETAL FALL
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Cultural Management
Reduce fruit corking.
Solubor
Borosol
+++
+++
1 lb
at first cover
1 pt
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 43).
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 elevated leaf nitrogen levels and vegetative growth. Do not apply calcium chloride when temperatures are above 85°F, and DO NOT tank mix with Solubor or Apogee. All calcium sprays should be applied dilute for maximum response, especially for bitter pit control in late season cover sprays when fruit are becoming waxy. See Fertility Management section (page 43).
Plant Growth Regulators
Reduce fruit russetting on susceptible cultivars (esp. Golden Delicious).
(GA4+7)
Pro-Vide 10SG
Novagib 10L
++++
++++
60 - 100 g
20-26 fl oz
12
4
None
At petal fall, begin the first of four applications at 7- to 10-day intervals. See Growth-Regulating Chemicals section (page 66) 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 on page 69.
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.
Initiate vegetative growth control applications.
Apogee
++++
Use at TRV calculated A.I./acre.
12
45
See Apogee table in Growth-Regulating Chemicals section (page 71). 14
PETAL FALL (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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, Rally, Indar, or Procure can be effectively used in a postsymptom treatment. See discussion under Fungicides and Bactericides (page 53).
Fungicides
captan 50W or
4L or
80W or
80WDG
2 lb
1 qt
1.25 lb
1.25 lb
8 lb
4 qt
5 lb
5 lb
96
96
24
24
0
0
0
0
If Rubigan, Rally, Indar, 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 10-14 days, or follow combination sprays with lower rates of captan or metiram in 5-7 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.
Control summer diseases (general).
captan 50W or
4L or
80 W or
80 WDG
+
Polyram 80 W or
mancozeb
80W
75 DF
4F
+++++
+++++
+++++
+++++
+++++
1¼ lb
0.62 qt
0.79 lb
0.79 lb
¾ lb
¾ lb
¾ lb
0.6 qt
5 lb
2½ qt
3.15 lb
3.15 lb
3 lb
3 lb
3 lb
2.4 qt
96
96
96
96
77
77
77
77
If Captan 80W or 80WDG is used the REI is 24 hours.
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
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Control summer diseases (general) (continued).
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.
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. The EBI fungicides have very little Brooks spot activity. If one of them is used, combine it with a full rate of protectant.
Control powdery mildew.
Fungicides
Bayleton 50DF
+++++
0.5 to 2 oz
2 to 8 oz
12
45
If Rally, Rubigan, Indar, or Procure is 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.
Insecticides
Agri-Mek 0.15EC
+
oil
+++++
2.5 oz
10 oz
12
28
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.
Control European red mite.
Apollo SC
Savey 50WP
Zeal 72WDG
Portal 0.4EC
Envidor 2SC
++++
++++
+++++
+++++
+++++
—
—
—
—
—
4 oz
3 oz
2 to 3 oz
1 to 2 pt
16 to 18 oz
12
12
12
12
12
45
28
28
14
7
Apply these products between petal fall and third cover or when mites reach one adult per leaf. Portal will also control leafhoppers. See page 38 for resistance management of European red mite.
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
PETAL FALL (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Control plum curculio.
Insecticides
Guthion 50WP
Imidan 70WP
Avaunt 30WG
Actara 25SDG
Voliam Flexi WDG
Calypso 4F
Clutch 50WDG
Sevin 50WP
+++++
+++++
+++++
+++++
+++++
++++
+++
+++
½ lb
¾ lb
—
—
—
—
—
½ lb
2 lb
3 lb
5 to 6 oz
4.5 to 5.5 oz
6 oz
4 to 8 oz
3 oz
1 lb
48h, 14d
24
12
12
12
12
12
12
21
7
28
35
35
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 10 days later. Read about re-entry interval for Guthion in the Insecticides and Miticides section (page 56).
Control Oriental fruit moth.
Insecticides
Guthion 50WP
Imidan 70WP
Voliam Flexi
Avaunt 30WG
Sevin 50WP
Assail 30SG
Calypso 4F
Clutch 50WDG
+++++
++++
+++++
++++
++++
++++
++++
+++
½ lb
¾ lb
—
—
½ lb
—
—
—
2 lb
3 lb
4-7 oz
5 to 6 oz
2 lb
5 to 8 oz
4 to 8 oz
3 oz
48h, 14d
24
12
12
12
12
12
12
21
7
35
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 56).
Control San Jose scale.
Insecticides
Diazinon 50WP
Guthion 50WP
Esteem 0.86EC
Centaur 70WP
Movento 2SC
Assail 30SG
summer oil
+++++
++++
+++++
+++++
++++
+++
+++
1 lb
½ lb
—
—
—
—
—
4 lb
2 lb
4 oz
34.5 oz
6-9 oz
8 oz
1 to 2%
24
48h, 14d
12
12
24
12
12
21
21
45
14
7
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 rosy apple aphid.
Insecticides
Provado 1.6F
Actara 25WP
Assail 30SG
Calypso 4F
Movento 2SC
+++++
+++++
+++++
+++++
++++
2 oz
—
—
—
—
4 to 8 oz
4.5 oz
2.5 to 4.0 oz
2 to 4 oz
6 to 9 oz
12
12
12
12
24
7
35
7
30
7
If an insecticide was not applied for rosy apple aphid at pink, or if control was poor, an insecticide should be applied.
An adjuvant must be applied with Movento.
See section on Rosy Apple Aphid resistance section (page 38). 17
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Control white apple leafhopper.
Insecticides
Sevin 50WP
Actara 25WDG
Assail 30SG
Calypso 4F
Provado 1.6F
Avaunt 30WG
+++++
+++++
+++++
+++++
+++++
+++++
½ lb
—
—
—
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.
Control spotted tentiform leafminer.
Insecticides
Actara 25WDG
Delegate WG
Provado 1.6F
SpinTor 2SC
Assail 30SG
++++
+++++
++++
+++++
++++
—
—
1 to 2 oz
—
—
4.5 oz
4.5 oz
4 to 8 oz
5 to 8 oz
1.1 oz
12
4
12
4
12
35
7
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 green fruitworm.
Insecticides
See insecticides for codling moth control.
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. 18
FIRST COVER
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Disease Management (Same fungicides as used in Petal Fall Spray)
Insect Management
Control codling moth.
Monitor codling moth adult activity.
Insecticides
Delegate 25WP
Altacor 35WDG
Voliam Flexi
Belt 4SC
Guthion 50WP
Imidan 50WP
Intrepid 2F
Rimon 0.83EC
Assail 30SG
Calypso 4F
CYD-X
*****
+++++
+++++
+++++
++++
++++
++++
++++
++++
++++
++++
++++
—
—
—
—
½ lb
¾ lb
—
—
—
—
—
4.5 to 7 oz
2.5 to 4.5 oz
4 to 7 oz
3 to 5 fl oz
2 lb
3 lb
10 to 16 oz
20 to 40 oz
4 to 8 oz
4 to 8 oz
1 to 3 oz
4
4
12
12
48h, 14d
24
4
12
12
12
4
7
14
35
14
21
7
14
14
7
30
0
See IPM Practices for codling moth (page 32) 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 or Rimon for first generaton codling moth, 2 applications at 14-day intervals should be made, the first at 100-200 DD.
CYD-X is a virus that controls only codling moth. Frequent applications (7-10 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 12)
*****
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. 19
SECOND COVER AND LATER SPRAYS
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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 13 through 18) and Fertility Management section (page 43).
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).
++++
See Fertility Management Recommendations section (page 43) for fertilizer use suggestions and complete recommendations.
Provide proper nutrition for moderate tree growth and good fruit quality.
Collect leaf samples in July to mid-August for leaf analysis.
+++++
See Fertility Management Recommendations section (page 43) for complete details.
Select lateral limbs, strip whorls, establish wide crotch angles with toothpicks or clothespins, and prop limbs to good limb angles (60-90° for central leader trees and 75-85° below vertical for high density, slender, spindle-type trees).
++++
Tree training is mandatory to develop proper lateral branching and limb position.
Achieve proper tree training, and control tree size and density for good light and spray penetration.
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).
++++
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. 20
SECOND COVER AND LATER SPRAYS (continued)
Rate per2
Goals
Options
Relative1
Effectiveness(+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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 on page 69.
See Chemical Fruit Thinning Sprays (page 67) and Apple Thinning Recommendations chart (page 69) in Growth-Regulating Chemicals section.
Enhance return bloom.
Fruitone L
Ethrel
+++
+++
2 oz
16-72
fl oz
48
96
Research studies in the Southeast have found that NAA or Ethrel treatments can improve return bloom. Ethrel rate depends on many factors including cultivar and crop load. Refer to table on page 68.
Control ground suckers around base of trunk.
Tre-Hold A-112 Sprout Inhibitor -
Also use herbicides approved for sucker control. See notes in Herbicide section (page 62) for Rely, Gramoxone.
++++
Use 10,000 ppm (10 oz/1 gal) as a low- pressure, large-droplet handgun application.
12
0
See Sucker Control (page 71) for specific recommendation details.
Delay preharvest fruit drop and delay fruit maturity.
ReTain
+++++
2 oz
One 333- gram pouch per acre (50 g a.i.)
12
7
Single Pick Harvest. Applying one pouch of ReTain per acre 4 weeks prior to the anticipated beginning of the normal harvest period of untreated fruit for the current season will delay the harvest period by 7-10 days.
Multiple Pick Harvest. Applying one pouch of ReTain per acre 1 to 2 weeks prior to the anticipated beginning of the normal harvest period of untreated fruit for the current season will improve quality and storage potential of later picked apples (2nd and 3rd pick fruit). Applications at this time will not typically delay the start of the harvest, but will help control the maturation rate of the later harvests.
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. 21
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Delay or reduce preharvest fruit drop or both.
Preload NAA (Fruitone-L)
++++
2 oz
48
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 (Fruitone L)
+
4 to 8 oz
48
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 66) for details.
Reduce fruit russetting in susceptible varieties.
Pro-Vide 10SG
Novagib 10L
(continue applications started at petal fall)
++++
++++
60-100 g
20 oz per acre/appl
12
4
0
See Growth-Regulating Chemicals section (page 66) for recommendation details.
Pro-Vide 10SG
+++
100-200 g
12
0
Reduce fruit cracking of susceptible varieties (e.g., Stayman).
Novagib 10L
+++
2 to 4 pt per acre/appl
4
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 66) for details.
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 66) 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. 22
SECOND COVER AND LATER SPRAYS (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Disease Management
Scout orchard.
Prune out fire blight strikes.
*****
*****
Fungicides
captan
50W or
4L or
80W or
80WDG
+++++
+++++
2 lb
1 qt
1.25 lb
1.25 lb
8 lb
4 qt
5 lb
5 lb
96
96
24
24
0
0
0
0
Control summer diseases (white rot, bitter rot, black rot, sooty blotch, flyspeck, black pox).
ziram 76DF or 76WDG
++++
2 lb
8 lb
48
14
Thiram 65W
++++
1.7 lb
6.8 lb
24
0
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.
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.
Pristine 38W
+++++
—
14.5 to 18.0 oz
12
0
captan
50W or
4L or
80W or
80 WDG
+
Topsin M70WP
+++++
2 lb
1 qt
1.25 lb
1.25 lb
2 to 4 oz
8 lb
4 qt
5 lb
5 lb
8 to 16 oz
96
96
24
24
96
0
0
0
0
1
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.
If Captan 80W or 80WDG is used then the REI is 48 hours for this and other combinations below.
ziram 76DF or 76WDG
+
Topsin M70WP
+++++
2 lb
2 to 3 oz
8 lb
8 to 12 oz
48
14
23
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Control summer diseases (continued).
thiram 75WDG
+
Topsin M70WP
+++++
2 lb
2 to 4 oz
8 lb
8 to 16 oz
24
0
captan
50W or
4L or
80W or
80 WDG
+
metiram 80DF
or
mancozeb 75DF
+++++
1.25 lb
1 pt
0.79 lb
0.79 lb
¾ lb
¾ lb
5 lb
2.5 qt
3.15 lb
3.15 lb
3 lb
3 lb
77
77
Metiram and mancozeb cannot be used within 77 days of harvest.
captan
50 W or
4 L or
50W or
50WDG
+
ziram 76DF, 76WDG or
thiram 65WDG
+
Topsin M70WP
+++++
1 lb
½ qt
0.63 lb
0.63 lb
1 lb
1 lb
2 to 4 oz
4 lb
1 qt
2.52 lb
2.52 lb
4 lb
4 lb
8 to 16 oz
96
14
If thiram is used in this combination, the REI is 96 hours and the PHI is 0 days.
captan
50 W or
4 L or
80W or
80WDG
+
ProPhyt
+++++
2 lb
1 qt
1 ¼ lb
1 ¼ lb
½ to ¾ qt
8 lb
4 lb
5 lb
5 lb
2 to 3 qt
96
0
This is the best combination for control of Glomerella leaf spot. Make first spray around June 15th or when first leaf spot symptoms appear and continue spraying every 10-14 days until harvest. Use high rate of Prophyt where Glomerella leaf spot is a problem.
The REI is 24 hours if Captan 80W or 80WDG is used.
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.
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.24
SECOND COVER AND LATER SPRAYS (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
interval
(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.
Pristine 38W
+++++
14.5 to 18.5 oz
12
0
Make first application of Pristine 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. Do not make more than 4 applications or apply more than 72 oz of Pristine per season.
Insect Management
Monitor pheromone traps weekly for adult activity.
*****
Insecticides:
(See First Cover.)
*****
Control codling moth and Oriental fruit moth.
OFM Mating Disruption
Isomate-M100
CheckMate OFM-F
+++++
+++++
100
0.3 to 2.5 oz
See IPM practices for codling moth (page 32) and Oriental fruit moth (page 33) to determine the need for and timing of insecticide sprays. Insecticides generally provide 2 weeks’ control, but under high populations applications should be shortened to 10 days. Keep trap bottoms clean, and replace lures monthly.
Mid- and late-season OFM can be controlled very well with mating disruption. If a mating disruption product effective against OFM was not applied before bloom, an application should be made before emergence of second generation adults (late May to early June).
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. 25
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
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 34) to determine the proper timing of insecticide applications.
Clustering of fruit is conducive to higher levels of tufted apple bud moth injury.
Insecticides
Intrepid
Delegate 25WG
Altacor 35WDG
Voliam Flexi
Belt 4SCV
Danitol 2.4EC
Avaunt 30WDG
+++++
+++++
+++++
+++++
+++++
+++++
++++
—
—
—
—
—
—
—
6 to 12 oz
4.5 to 7 oz
2.5 to 4.5 oz
4 to 7 oz
3 to 5 fl oz
10.6 to 21.3 oz
5 to 6 oz
4
4
4
12
12
24
12
14
7
14
35
14
14
28
See Insecticide Resistance Management section (page 37) 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 TABM (page 34) 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 CM.
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. 26
SECOND COVER AND LATER SPRAYS (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Control apple maggot.
Erect red sticky spheres in early June to monitor adults.
****
Erect sticky traps baited with fruit essence lures on outside rows nearest abandoned orchards or other sources of flies. Check weekly. Threshold level is a cumulative of 5 flies per trap. If the threshold is exceeded again 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
—
—
—
—
—
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
C
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
Clutch 50WDG
Centaur 70WP
+++++
+++++
+++++
+++++
+++++
+++++
+++++
1 oz
—
—
—
—
—
—
4 oz
2 to 2¾ oz
2.5 to 4.0 oz
2 to 4 oz
5 to 6 oz
2 oz
34.5 oz
12
12
12
12
12
12
12
7
14
7
30
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. 27
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
interval
(hours)
Preharv.
interval
(days)
Comments
Control spotted tentiform leafminer.
Insecticides
Lannate 90SP
Delegate WG
SpinTor 2SC
Vydate 2L
Provado 1.6F
Actara 25WDG
Assail 30SG
Calypso 4F
Clutch 50WDG
++++
+++++
+++++
++++
+++
++++
++++
++++
++++
¼ lb
—
—
1 to 2 pt
2 oz
—
—
—
—
1 lb
4.5 to 7 oz
4 to 8 oz
4 to 8 pt
8 oz
4.5 oz
2.5 oz
2 to 4 oz
3 oz
72
4
4
48
12
12
12
12
12
14
7
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
Provado 1.6F
Actara 25WDG
Assail 30SG
Calypso 4F
Clutch 50WD
+++++
+++++
+++++
+++++
+++++
1 to 2 oz
—
—
—
—
4 to 8 oz
4.5 oz
2.5 to 4.0 oz
2 to 4 oz
2 oz
12
12
12
12
12
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
Actara 25WDG
Assail 30SG
Movento 2SC
+++++
+++
+++++
++++
1 lb
—
—
—
4 lb
4.5 oz
4 to 8 oz
6 to 9 fl oz
24
12
12
24
14
35
7
7
Applications should be made near the second or third cover spray. Comstock mealybug is an unpredictable pest, and orchards with a history of problems are most susceptible.
Control woolly apple aphid
Insecticides
Provado 1.6F
Movento 2SC
Thionex 40WP
Diazinon 50WP
+++
+++
+++
+++++
—
—
1 lb
1 lb
6 to 8 fl oz
6 to 9 fl oz
4 lbs
4 lbs
12
12
24
24
7
7
21
21
Woolly apple aphid control can be difficult if insecticides are applied after populations reach large densities. Use a threshold of 10% infested shoots.
An adjuvant must be used with Movento.
Control redbanded leafroller.
Insecticides
See insecticides for tufted apple bud moth.
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.
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. 28
SECOND COVER AND LATER SPRAYS (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Control lesser apple worm.
Insecticides
See insecticides for codling moth.
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.
Control dogwood borer.
Insecticides
Lorsban 50W,
4E
++++
+++++
3 lb
1.5 qt
—
—
96
96
28
28
Apply insecticides with a handgun sprayer to the trunk, especially to burr knots and graft unions. Moths can lay eggs from mid May through September, so treatment before July 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 1 mite/leaf (50% infested leaves) should be used to minimize stress to trees.
Miticides
Acramite 50WS
Nexter 75WP
Portal 0.4EC
Apollo SC
Savey 50DF
Zeal 72WDG
Envidor 2SC
Vendex 50W
Danitol 2.4EC
wettable sulfur
summer oil
+++++
++++
+++++
++++
++++
+++++
+++++
++++
++++
+
++
—
—
—
—
—
—
—
¼ lb
—
1½ to 3½ lb
½ to 1 gal
¾ to 1 lb
4.4 oz
1 to 2 pt
4.0 oz
3.0 oz
2 to 3 oz
16 to 18 oz
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
14
45
28
28
14
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.
29
SECOND COVER AND LATER SPRAYS (continued)
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(days)
Comments
Weed Management
Spot-treat with herbicide to control difficult-to-manage perennial weeds.
glyphosate
*****
See Weed Response to Herbicide table
(pages 50 to 52).
Apple trees are especially sensitive to glyphosate applied in late summer and fall. Avoid contacting tree bark and especially foliage.
.
POSTHARVEST
Rate per2
Goals
Options
Relative1
Effectiveness (+)
or
Importance (*)
100 gal
Acre
Re-entry
Interval
(hours)
Preharv.
Interval
(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 66) for complete details.
To maintain apple flesh firmness, fruit acidity and minimize scald.
SmartFresh
++++
See Growth-Regulating Chemicals section (page 66) 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. 30
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:
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).
Step 4:
cu ft of foliage/acre
canopy density
(from Step 2)
X
(from Step 3)
=
1,000 cu ft
gallons of dilute solution
to be applied per acre for
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:
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:
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 ⅔ 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.
43,560 sq ft/acre
distance between rows (ft)
=
feet of row/acre 43,560 ft225 ft
=
1,742.4 ft
592,416 cu ft X 0.85 gal
1,000 cu ft
=
503.5 gal/acre will apply a dilute application to runoff. 31
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 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.
Table 3. How to calculate concentrate application rates.
Concentrate pesticide
application
(3X water rate)1
Dilute pesticide TRV gallonage
352 gal/acre
Concentrate rate
=
3X
=
117 gal/acre
Concentrate pesticide chemical load per acre
(2X to 4X)2
Rate of pesticide per 100 gal
X
Dilute pesticideTRV gal/acre
2.0 X 352
100 gal
=
100
=
7.1 lbs/acre
5X or greater3
Rate of
pesticide per 100 gal
X
Dilute
pesticide TRVgal/acre
X 0.8
=
2.0 X 352 X 0.8
=
100 gal
100
5.6
lbs/acre
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.
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. 32
IPM Practices for Selected Pests
Plum Curculio
Adults overwinter in leaf litter in and around orchards. In the spring when the daily maximum temperature exceeds 70°F, adults emerge, mate, and lay eggs under fruit skin. Adults generally begin to enter orchards shortly before bloom, but depending on weather conditions, new adults can continue to enter until shortly after petal fall. 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 in some areas of the Southeast.
Scouting and Control: After bloom, check twice weekly for plum curculio adults or feeding and egg-laying scars. Typically, an insecticide at petal fall is sufficient for control, but occasionally emergence may be protracted and a second application at first cover may further suppress damage.
Apple Maggot
The apple maggot usually completes one generation per season at elevations above 2,000 feet and two generations at less than 1,200 feet. However, depending upon the year, fly activity can extend from June through September. Adult fly emergence from overwintering pupae in the soil is unpredictable and can occur from late May to August, but the peak emergence is usually between mid July and 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 them 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. If fly emergence is early in the season, some of their progeny emerge the same season rather than overwinter. In addition, a small percentage of flies may not emerge until 2 to 4 years later.
Weather conditions are important in dictating the timing and length of fly emergence. Pupae that are 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. Also, abandoned orchards (or even a few nonsprayed trees) and wild hawthorn trees adjacent to apples are potential sources of flies, and are a threat to commercial orchards located within a distance of about 400 yards.
Monitoring and Control: Monitor apple maggot adults with red sticky spheres that are baited with a fruit essence lure. 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, and remove the fruit adjacent to the sphere. In orchards with a history of damage, also place traps within orchards on the southern side of trees. When using baited spheres, apply an insecticide after catching five flies cumulatively. Repeat an application at 14-day intervals if captures again reach 5 flies. Because the timing of emergence is difficult to predict, insecticide sprays should not be based on population trends of the previous year.
Codling Moth
Codling moths begin to emerge and mate during April or early May, depending on location, and complete two generations per season. Depending on location and the year, a partial or complete third generation may occur. 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.
In recent years the codling moth has become a serious problem in orchards throughout the Southeast. Factors associated with problem orchards are (1) bin piles stored near orchards and/or (2) insecticide-resistant populations. Bins are an ideal environment for overwintering larvae, and when they complete their development the following spring the adults disperse to nearby orchards. Recent research suggests that orchards within 100 to 150 yards of bin piles are particularly prone to infestation. Insecticide resistance has been detected in a number of orchards where problems have persisted for one or two years.
Codling Moth Degree-Day Model
The codling moth degree-day model is used to predict adult emergence and egg hatch of each of the two to three generations that occur each year. The model has been in existence for more than 20 years, and it has worked well throughout the US. However, the model may not be entirely accurate where insecticide-resistant populations occur or where bin piles are a source of codling moths, because these moths emerge later than predicted by the model.
Base a decision to spray insecticides against codling 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 two to three 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 33
orchards near the tight cluster stage of bud development, and checked one to two times per week. Hang traps at a density of one trap per 10 acres of orchard. Traps hung in the upper third of the canopy catch more moths than those in the lower canopy and are a preferred location. Once biofix is determined, degree days are calculated daily. It is only necessary to check traps once per week after biofix is determined. Use the table on page 36 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 the previous year and pheromone trap catches that do not exceed 10 moths per trap per week anytime during the first generation (to about 850 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: 100 to 150 if using a product which depends primarily on ovicidal activity for control (i.e., Intrepid or Rimon), and 250 if using an insecticide that targets early stage larvae. Additional applications may be necessary if trap captures remain high (greater than 10 moths per trap).
A second emergence of overwintering adults sometimes occurs between 500 and 800 degree days after biofix. This is often referred to as the “B peak” and may be associated with insecticide-resistant individuals in the population. Hence, pheromone trapping is important throughout the flight period.
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 (no first-generation damage is observed and pheromone trap catches never exceed 2 to 3 moths per trap per week between 900 and 1,900 DD after biofix). Low-density orchards require one insecticide application, and recent research indicates the optimum timing is between 1,300 and 1,400 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 and higher pheromone trap catches requiring at least two insecticide applications at 14-day intervals, starting about 1,300 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 at shorter intervals may be necessary. This often occurs in orchards adjacent to an abandoned orchard or where old bins are placed near an orchard.
Relationship between degree-day accumulations from biofix and percentages of
codling moth adult emergence and egg hatch.
Cumulative
D
egree 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
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 ½-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. 34
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 36 uses daily maximum and minimum temperatures to determine daily DDs for Oriental fruit moth (base 45°F). 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.
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 (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 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, more effective 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 35 (45°F). 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 may be necessary; make the first application at about 10 percent egg hatch, which occurs at about 800 DD after biofix, and the second application 14 days later. Where populations are low or if using a long residual insecticide (Intrepid, Delegate, Altacor, or Voliam Flexi), one application per generation should be made 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 in early to mid-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). Under high populations, 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- to late 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 or reduces 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 codling moth and Oriental fruit moth. Oriental fruit moth is much easier to control with mating disruption compared with codling moth; use both mating disruption and insecticides against moderate to high codling moth populations. 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 (such as abandoned orchards or bin storage areas). 35
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. Companies are now marketing pheromone dispensers that contain both codling moth and oriental fruit moth so that a single dispenser type can be used for mating disruption of both insects. Dispensers vary in the amount of pheromone they contain and the length of time during which pheromone is emitted, so read the label beforehand to ensure that dispensers are used properly. Because both codling moth and Oriental fruit moth are potential pests in the Southeast, it is highly recommended that dual pheromone dispensers be used.
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, dispenser application should be completed by petal fall. For codling moth, best results are obtained when dispensers are hung in the upper third of the canopy, because this is where mating occurs.
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, insecticides applied at petal fall for other insects usually controls this first generation, so if using Oriental fruit moth dispensers only, application can be delayed until just before emergence of the second- or third-generation adults (950 and 1850 DD after biofix, respectively). If using sprayable pheromones for mating disruption, make the initial application when hand-applied dispensers are applied. If mating disruption is not used against this insect and pheromone trap captures remain low during the season, a single late-season application in mid to late August will help to suppress late-season populations.
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. In orchards using codling moth mating disruption, hang traps at a density of one trap per 3 acres in the upper canopy.
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 a complex of generalist predators (such as 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 late June). 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 mite density 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 rely on biological control or apply a miticide to prevent mites from increasing to damaging levels. For biological control with Stethorus punctum to occur, the ratio should be 2.5 S. punctum to 1 ERM. For S. punctum, count the number of adults and larvae observed during a 3-minute search around the periphery of mite-infested trees. Count the 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 numbers, and mite populations are between 5 to 10 mites per leaf, apply a miticide.
Where Alternaria blotch is a problem on Delicious apples, biological control is usually not an option. Alternaria blotch in the presence of mite injury can lead to premature defoliation, so mite populations must be maintained at very low levels. If preventive control measures are not used, miticides should be used when mites reach 1-2 mites.
Relationship between European red mite density per leaf and % infested leaves.
% Mite-Infested Leaves
(>1 mite/leaf)
Expected No.
% Mite-Infested Leaves
(>1 mite/leaf)
Expected No.
Mites per Leaf
Mites per Leaf
40
0.7
70
45
50
55
60
65
0.9
1.1
1.3
1.6
2.0
75
80
85
90
95
2.6
3.4
4.7
6.8
11.4
26.4 36
Codling moth degree days (50°F lower base, 88°F upper base) at various daily maximum and minimum temperatures.
Max
Min
54
56
58
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
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
2
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
3
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 (45°F lower base, 91°F upper base) at various daily maximum and minimum temperatures.
Max
Min
50
52
54
56
58
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
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
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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 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 such as 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 (such as organophosphate insecticides or EBDC fungicides). Multiple resistance involves multiple, independent resistance mechanisms, which often lead to resistance to chemicals from different families (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 because 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.
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. Currently, codling moth resistance is most important, but good resistance management strategies are required to prevent other pests from developing resistance. 38
Codling Moth
Insecticide-resistant codling moth populations are becoming more prevelant throughout the Southeast. Resistance to one or more registered insecticides, including Guthion, Intrepid, Rimon, and Assail, has been detected in a number of orchards in Georgia and North Carolina. In situations where codling moth resistance occurs, populations usually increase to large numbers, and frequent insecticide applications at short intervals (7 to 10 days) are necessary at critical times (between 400 and 800 DD after biofix) to prevent damage. However, such intense insecticide use may lead to higher levels of resistance, so alternative management strategies should be used in conjunction with insecticides. Using mating disruption is strongly encouraged as a resistance management tactic, as this will help reduce population densities more quickly than insecticides alone and, subsequently, the need for insecticide applications. After two to three years of continuous mating disruption, codling moth population densities can be reduced so that only one or two total insecticide applications are needed for season-long control. In addition, make an attempt to avoid using more than two insecticide applications against a single codling moth generation by incorporating codling moth virus (Cyd-X or Carpovirusine) applications into the spray program after two applications have been made. When choosing insecticides, rotate insecticides with different modes of action against each generation. For example, make two applications of the same insecticide against the first generation, but use an insecticide with a different mode of action against the second generation.
Rosy Apple Aphid
The rosy apple aphid has developed widespread resistance to Lorsban, and control failures with Thiodan, Asana, Ambush, and Diazinon have become more common in recent years. Consequently, neonicotinoid insecticides are now most commonly used for control. It is important to remember that all neonicotinoids (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 or (2) petal fall. Do not apply any insecticide with the same mode of action 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 developing resistant populations. To reduce this potential, in addition to a delayed dormant oil application, do not use the same miticide in successive years.
Resistance Management Strategies for Plant Pathogens
Resistance of plant pathogens to pesticides has become widespread over the past 30 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 (EBI) [fenarimol (Rubigan), myclobutanil (Rally), triflumazole (Procure), fenbuconazole (Indar)] 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. Some growers in NC have also had problems controlling scab with EBI fungicides, suggesting that resistance may be a problem here as well. 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 greater than 0.01 inch, an average daily temperature of 60°F or greater, and the accumulation of at least 198 degree-hours greater than 65°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 EBI fungicides, because this sets up an ideal situation for selection of resistant strains. Good orchard sanitation practices to maintain pathogen populations at low levels are also an important component of a resistance management program. 39
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). Johnsongrass is resistant to carboxylase herbicides (Fusilade DX), and horseweed and pigweed biotypes have developed resistance to glyphosate. 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. The label on dimethoate, phosmet, malathion, azinphosmethyl, formetanate, ethephon, NAA, and possibly others warns of this effect. 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 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. 40
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 waterlogged 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 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, fluroxypyr, and 2,4-D (Rely, Gramoxone Max, Starane Ultra, 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 burndown 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.
3. Spring/Summer Split. (Due to changes in label, this option is available for non-bearing orchards only.) The registration of Chateau allows for a spring/summer split application time. However, Chateau is the only herbicide with label flexibility to allow this sequential application program. Chateau at 6 to 8 ounces per acre with a nonselective postemergence herbicide can be applied in mid March. This application will last through May and into 41
June. In June when control from the initial application begins to fail, an additional application of Chateau at 6 to 8 ounces per acre with either paraquat or Rely for nonselective postemergence weed control should be applied. The Sinbar label for non-bearing orchards allows the same use pattern as well.
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 which weed species are present. Scouting allows growers to control escaped weeds with a timely herbicide application and identify difficult-to-control weeds early. 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 should be removed before they produce seed. Remove by hand or with a spot treatment with a nonselective postemergence herbicide like glyphosate or fluroxypyr (Roundup and others, as well as Starane Ultra). Scouting also helps growers recognize poorly controlled weeds and adjust their weed management program. Another aspect growers should consider is the potential for weed infestation from the border of the orchard. Weeds in these areas produce seeds that may 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: glyphosate (various formulations and rates; see label for details), 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 post-transplant stress in 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 serious 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 2½ miles of the orchard is at risk from insecticide applications. Bees are highly attracted to flowers in the ground cover. Before applying ins