Small Grain Production Guide
Revised March 2013
Small Grain Production Guide
Revised March 2013
Prepared by
Randy Weisz, Crop Science Extension Specialist, NC State University
With additional contributions from
Gaylon Ambrose, County Extension Agent, Beaufort County Cooperative Extension
Steve Bambara, Retired Entomology Extension Specialist, NC State University
Christina Cowger, USDA–ARS, Plant Pathologist, NC State University
Carl Crozier, Soil Science Extension Specialist, NC State University
Wesley Everman, Weed Science Extension Specialist, NC State University
Ron Heiniger, Crop Science Extension Specialist, NC State University
D. Ames Herbert, Jr., Professor, Entomology, Virginia Polytechnic Institute
David Jordan, Crop Science Extension Specialist, NC State University
Paul Murphy, Small Grains Breeder, NC State University
Dominic Reisig, Entomology Extension Specialist, NC State University
Published by
North Carolina Cooperative Extension Service
College of Agriculture & Life Sciences
North Carolina State University
Acknowledgments
This publication is supported in part by a grant from the NC Small Grain Growers
Association, Inc. The association provides funds to supplement public appropriations
and research programs at NC State University for the benefit of the small grain
industry, general consumers, and the public at large.
Contents
1. Small Grain Growth and Development . . . . . . 1
2. Wheat Enterprise Budgets . . . . . . . . 5
3. Small Grain Variety Selection . . . . . . . 9
4. To Plant or Drill: Does Row Spacing Matter? . . . . . 13
5. Small Grain Planting Dates . . . . . . . . 14
6. Beating Soybean Harvest: A Very Early Wheat-Planting System . . . 16
7. Small Grain Seeding Rates for North Carolina . . . . . 19
8. Nitrogen Management for Small Grains . . . . . . 25
9. Nutrient Management for Small Grains . . . . . . 32
10. Insect Pest Management for Small Grains . . . . . . 39
11. Insect Pests of Stored Small Grains . . . . . . 51
12. Small Grain Disease Management . . . . . . . 56
13. Small Grain Weed Control . . . . . . . . 70
1. Small Grain Growth And Development
By Randy Weisz
Small grains respond best to inputs when they are applied at specific growth stages. Therefore, it is
important to understand how small grains develop so you can identify the different growth stages and
properly time applications of pesticides, nitrogen, and other inputs. Small grain development can be divided
into four phases: vegetative growth or tillering, stem extension, heading and flowering, and kernel formation
and ripening. The specific growth stages associated with these phases have been described in several scales.
The most popular scales are the Feekes and Zadoks stages of development (Table 1-1). Both scales will be
described in this chapter, but we will use the Zadoks system in the rest of this production guide.
Vegetative Growth And Tillering
In NC, wheat is typically planted from mid-October
through late November. Plants emerge about one
week after planting (Feekes 1 or Zadoks 11, see
Figure 1-1), and leaves begin to develop on the
mainstem or shoot. When the fourth leaf unfolds,
the first tiller starts to grow (Feekes 2 or Zadoks
21), and a new tiller is produced with every
subsequent unfolding of a leaf on the mainstem.
Tillering continues as long as the plants are healthy,
unstressed, and the temperature is warm. Tillers are
important because each tiller can only produce one
grain head, and tillers that develop in the fall often
produce the largest heads and contribute the most
to crop yield. Tillering slows down or stops when
winter weather turns cold. When the weather
warms up again in late January or February, another
brief period of further vegetative growth occurs
when spring tillers can grow if nitrogen is available.
In NC, tillering and vegetative growth usually end
between late Febuary and mid-March (Feekes 4-5 or
Zadoks 30).
Growth And Development 1
Stem Extension
During Feekes growth stage 4-5 or Zadoks 30, small
grains switch from producing tillers to starting
reproductive growth. In the first phase of
reproductive growth, the stems extend and the plant
grows taller. The growing point, which was below
ground during tillering, moves upward through the
elongating stem and begins the transition into what
will become a head of grain. The first easily
2 Growth And Development
Emergence
Feekes 1
Zadoks 11
Three leaves
Feekes 1
Zadoks 13
First Tiller
Feekes 2
Zadoks 21
Three Tillers
Feekes 2
Zadoks 23
Tillering Ends
Feekes 4-5
Zadoks 30
Figure 1-1. Vegetative growth and tillering phase of wheat development. More details and pictures of these growth stages can be
found online.
First Joint
Feekes 6
Zadoks 31
Flag Leaf Visible
Feekes 8
Zadoks 37
Flag Leaf Ligule Visible
& Boot Swollen
Feekes 9 to 10
Zadoks 39 to 45
Boot Splitting
Feekes 10
Zadoks 47
Figure 1-2. Stem extension. More details and pictures of these growth stages can be found online.
detected sign that this has started is the appearance
of the first node or joint at Feekes growth stage 6 or
Zadoks 31 (see Figure 1-2). The joint is a small
swelling of the stem that somewhat resembles a
joint on a human finger. As the stem continues to
develop, several joints may appear. Knowing this is
important for the small grain producer: the
developing grain head is always inside the stem just
above the highest joint. That means that if the stem
is damaged by being driven over, a freeze, or
lodging, the developing head is also likely to be
damaged. Additionally if liquid nitrogen fertilizer is
applied after jointing, the developing grain head is
almost always burned, resulting in potential yield
reductions.
The flag leaf is the last leaf to develop on the small
grain plant. The growth stage when it first appears
at the top of the stem is defined as Feekes 8 or
Zadoks 37. As the flag leaf unfolds, the ligule or
collar at the base of the leaf become visible at
Feekes 9 or Zadoks 39. At this time the developing
grain head is getting large enough that the stem
containing it swells. This swelling is called the boot.
As the grain head continues to grow it eventually
causes the boot to split open at Zadoks 47.
Heading and Flowering
The plant starts the heading phase of
development when the first spikelet has emerged
from the boot at Feekes 10.1 or Zadoks 50.
Over the next few days the grain head will fully
emerge from the boot at Feekes 10.5 or Zadoks
58 (see Figure 1-3). About one week later, the
head will begin to shed pollen as flowering
begins.
Kernel Formation
A few hours after pollination, grain kernels begin to
form. Dry matter starts accumulating in the kernels,
and a clear to milky fluid can be squeezed from
them. This is known as the milk stage of kernel
formation. Forage harvest during the milk stage
results in the best combination of nutrient quality
and yield. With continued growth and water loss,
the kernel content changes from a milky fluid to a
doughy or mealy consistency. This is called the soft
dough stage. At soft dough, the green color of the
head begins to fade (Photo 1-1) and harvesting
forage at this time results in maximum dry matter
Growth And Development 3
¾ Of Head Visible
Feekes 10.4
Zadoks 56
Fully Headed
Feekes 10.5
Zadoks 58
Flowering
Feekes 10.51 to 10.53
Zadoks 60 to 68
Figure 1-3. Heading and flowering. More details and pictures of
these growth stages can be found online.
Photo 1-1. Soft dough. Feekes growth stage
11.2 or Zadoks 85.
yield. When the water content of the
kernels drops to about 30 percent, the
plant loses most of the green color but
the kernels can still be cut by pressing
with a thumbnail. This is called the hard
dough stage. This marks the end of all
insect and disease pest management.
When the kernels reach 13 to 14 percent
moisture, the grain is harvest ripe (Photo
1-2).
References
Some materials in this chapter were adapted from
these references:
Alley, M. M., D. E. Brann, E. L. Stromberg, E. S.
Hagood, A. Herbert, and E.C. Jones. 1993.
Intensive Soft Red Winter Wheat: A Management
Guide (Publication 424-803). Blacksburg:
Virginia Polytechnic Institute, Cooperative
Extension Service.
Hilfliger, E. (Ed.). 1980. Wheat-documenta. CIBA-GEIGY,
Technical Monograph. Basle,
Switzerland: CIBA GEIGY Ltd
Strand, L. 1990. Integrated Pest Management for Small
Grains (Agricultural and Natural Resources
Publication 3333). Oakland, CA: University of
California Statewide IPM Project.
4 Growth And Development
Table 1-1. Feekes and Zadoks scales of small grain development.
Feekes Zadoks General Description
Vegetative Growth & Tillering
1 10 1st leaf through coleoptile
12 2nd leaf unfolded
13 3rd leaf unfolded
2 21 Main shoot and 1 tiller
22 Main shoot and 2 tillers
23 Main shoot and 3 tillers
3 26 Main shoot and 6 tillers
4-5 30 Tillering ended, leaf sheaths strongly erected
Stem Extension
6 31 1st node detectable
7 32 2nd node detectable
8 37 Flag leaf just visible
9 39 Flag leaf ligule visible
10 45 Boots swollen
Heading and Flowering
10.1 50 1st spikelet visible through split boot
10.2 52 ¼ head emerged
10.3 54 ½ head emerged
10.4 56 ¾ head emerged
10.5 58 Head fully emerged
10.51 60 Start of flowering
Kernel Formation
10.54 71 Milk stage - watery ripe
11.1 75 Milk stage - medium milk
11.2 85 Soft dough
87 Hard dough
11.3 91 Dry matter accumulation ends
11.4 92 Harvest ripe
Photo 1-2. Harvest ripe. Feekes growth stage
11.4 or Zadoks 92.
2. Wheat Enterprise Budgets
By Randy Weisz and Ron Heiniger
In NC, wheat is grown in a double-cropped soybean production system. This allows the risk of crop failure
to be spread across two harvests and increases income potential. A full-season soybean budget is included
for comparison with wheat double-cropped bean production. At the wheat and soybean prices that the
market has been offering in 2012 and 2013 this double-cropped system is highly profitable. The wheat
budgets presented here are based on practices outlined throughout this production guide. If you have a
smaller farm, smaller equipment, or use more inputs than assumed in these budgets, costs will be higher
than those shown in the following tables. Please note that these budgets are for planning purposes only.
Items for All Wheat Bean Budgets
• Wheat and soybeans are planted with a Great
Plains 22-foot wide no-till drill.
• Pre-plant fertilizer to provide 27 pounds N, 70
pounds P2O5, and 100 pounds K2O per acre is
applied by a commercial applicator as 152 pounds
of diammonium phosphate (18-46-0) and 167
pounds of potassium chloride (0-0-60).
• Lime is applied once every three years and is
prorated across each season.
• All herbicides, fungicides, insecticides, and top-dress
N-fertilizer are applied using a HiBoy with a
90-foot boom.
• A broadleaf herbicide is applied in February.
• Top-dress N (100 pounds per acre) is applied in
March as 30% N solution.
• A fungicide is applied to the wheat between flag
leaf and heading.
• An insecticide is applied to the wheat either in
March tank-mixed with top-dress N, or in April
tank-mixed with the fungicide.
• Wheat and beans are harvested by combine with
a 30-foot wide header.
• All soybeans are Roundup Ready planted no-till.
• A herbicide application is made to the soybeans
pre-plant to help prevent development of
glyphosate resistance.
• Glyphosate is applied post-emergence.
• An insecticide is applied to all soybean acreage in
August.
• One-fourth of the land in production is rented at
$100 per acre.
Conventional-Till Wheat No-Till Beans
Budget
• In the fall, field preparation is made with two
passes of a 30-foot-wide disk harrow, and one
pass with a 29-foot-wide field cultivator.
• Wheat is planted at 1.5 million seeds per acre (35
seeds per square foot) or about 2.4 bags of seed
per acre.
• Soybeans are planted at 160,000 seed per acre.
No-Till Wheat No-Till Soybeans Budget
• In the fall, field preparation is limited to one
application of glyphosate applied pre-plant.
• Wheat is planted at about 2.7 bags of seed per
acre.
• Soybeans are planted at 160,000 seed per acre.
Full-Season No-Till Soybean Budget
• This budget is identical to the double-cropped
soybean budgets except that soybeans are planted
in May and expected to yield more, no pre-plant
N is applied, and the rates of P2O5, and K2O are
reduced.
Wheat Enterprise budgets 5
6 Wheat Enterprise budgets
Table 2-1. No-till wheat and double-cropped no-till Roundup Ready soybean budget.
Unit Quantity Price or Cost/Unit Total per Acre Your Farm
1. GROSS RECEIPTS
Wheat BU 55 $8.00 $440.00 ___________
Soybeans BU 30 $14.00 $420.00 ___________
TOTAL RECEIPTS: $860.00 ___________
2. VARIABLE COSTS
Wheat seed BU 2.7 $15.00 $40.50 ___________
Soybean RR seed THOU. 160 $0.36 $57.60 ___________
Pre-plant fertilizer
DAP LBS 152 $0.36 $54.72 ___________
Potassium chloride LBS 167 $0.32 $53.44 ___________
Commercial spreading ACRE 1 $6.00 $6.00 ___________
Top-dress N (30% solution) LBS 90 $0.62 $55.80 ___________
Lime (Prorated) TON 0.33 $48.50 $16.01 ___________
Herbicides for wheat ACRE 1 $21.54 $21.54 ___________
Herbicides for soybeans ACRE 1 $33.65 $33.65 ___________
Fungicides for wheat ACRE 1 $10.80 $10.80 ___________
Insecticides for wheat ACRE 1 $4.63 $4.63 ___________
Insecticides for soybeans ACRE 1 $11.85 $11.85
Crop insurance for wheat ACRE 1 $6.00 $6.00 ___________
Crop insurance for beans ACRE 1 $10.00 $10.00 ___________
Hauling wheat BU 55 $0.15 $8.25 ___________
Hauling soybeans BU 30 $0.15 $4.50 ___________
Tractor/Machinery ACRE 1 $25.48 $25.48 ___________
Labor HRS 1.35 $7.25 $9.79 ___________
Interest on Op. Cap. DOL $190.09 6.50% $12.36 ___________
TOTAL VARIABLE COSTS: $442.91 ___________
3. INCOME ABOVE VARIABLE COSTS: $417.09 ___________
4. FIXED COSTS
Tractor/Machinery ACRE 1 $39.06 $39.06 ___________
TOTAL FIXED COSTS: $39.06 ___________
5. OTHER COSTS
Land rent ACRE 0.25 $100.00 $25.00 ___________
General overhead DOL $442.92 4.5% $19.93 ___________
TOTAL OTHER COSTS: $44.93 ___________
6. TOTAL COSTS: $526.90 ___________
7. NET RETURNS TO RISK AND MANAGEMENT: $333.10 ___________
Wheat Enterprise budgets 7
Table 2-2. Full-till wheat and double-cropped no-till Roundup Ready soybean budget.
Unit Quantity Price or Cost/Unit Total per Acre Your Farm
1. GROSS RECEIPTS
Wheat BU 55 $8.00 $440.00 ___________
Soybeans BU 30 $14.00 $420.00 ___________
TOTAL RECEIPTS: $860.00 ___________
2. VARIABLE COSTS
Wheat seed BU 2.4 $15.00 $36.00 ___________
Soybean RR seed THOU. 160 $0.36 $57.60 ___________
Pre-plant fertilizer
DAP LBS 152 $0.36 $54.72 ___________
Potassium chloride LBS 167 $0.32 $53.44 ___________
Commercial spreading ACRE 1 $6.00 $6.00 ___________
Top-dress N (30% solution) LBS 90 $0.62 $55.80 ___________
Lime (Prorated) TON 0.33 $48.50 $16.01 ___________
Herbicides for wheat ACRE 1 $10.57 $10.57 ___________
Herbicides for soybeans ACRE 1 $33.65 $33.65 ___________
Fungicides for wheat ACRE 1 $10.80 $10.80 ___________
Insecticides for wheat ACRE 1 $4.63 $4.63 ___________
Insecticides for soybeans ACRE 1 $11.85 $11.85
Crop insurance for wheat ACRE 1 $6.00 $6.00 ___________
Crop insurance for beans ACRE 1 $10.00 $10.00 ___________
Hauling wheat BU 55 $0.15 $8.25 ___________
Hauling soybeans BU 30 $0.15 $4.50 ___________
Tractor/Machinery ACRE 1 $27.96 $27.96 ___________
Labor HRS 1.76 $7.25 $12.76 ___________
Interest on Op. Cap. DOL $183.59 6.50% $11.93 ___________
TOTAL VARIABLE COSTS: $432.47 ___________
3. INCOME ABOVE VARIABLE COSTS: $427.53 ___________
4. FIXED COSTS
Tractor/Machinery ACRE 1 $43.93 $43.93 ___________
TOTAL FIXED COSTS: $43.93 ___________
5. OTHER COSTS
Land rent ACRE 0.25 $100.00 $25.00 ___________
General overhead DOL $432.47 4.5% $19.46 ___________
TOTAL OTHER COSTS: $44.46 ___________
6. TOTAL COSTS: $520.86 ___________
7. NET RETURNS TO RISK AND MANAGEMENT: $339.14 ___________
8 Wheat Enterprise budgets
Table 2-3. Full-season no-till Roundup Ready soybean budget.
Unit Quantity Price or
Cost/Unit
Total per
Acre Your Farm
1. GROSS RECEIPTS
Soybeans BU 37 $14.00 $518.00 ___________
TOTAL RECEIPTS: $518.00 ___________
2. VARIABLE COSTS
Soybean RR seed THOU. 160 $0.36 $57.60
Fertilizer ___________
Pre-plant P2O5 LBS 65 $0.41 $26.65 ___________
Pre-plant K2O LBS 83 $0.55 $45.65
Commercial spreading ACRE 1 $6.00 $6.00 ___________
Lime (Prorated) TON 0.33 $48.50 $16.01 ___________
Herbicides for soybeans ACRE 1 $33.65 $33.65 ___________
Insecticides for soybeans ACRE 1 $11.85 $11.85
Crop insurance for beans ACRE 1 $10.00 $10.00 ___________
Hauling soybeans BU 37 $0.15 $5.55 ___________
Tractor/Machinery ACRE 1 $10.72 $10.72 ___________
Labor HRS 0.61 $7.25 $4.42 ___________
Interest on Op. Cap. DOL $98.14 6.50% $6.38 ___________
TOTAL VARIABLE COSTS: $234.48 ___________
3. INCOME ABOVE VARIABLE COSTS: $283.52 ___________
4. FIXED COSTS
Tractor/Machinery ACRE 1 $17.69 $17.69 ___________
TOTAL FIXED COSTS: $17.69 ___________
5. OTHER COSTS
Land rent ACRE 0.25 $100.00 $25.00 ___________
General overhead DOL $234.48 4.5% $10.55 ___________
TOTAL OTHER COSTS: $35.55 ___________
6. TOTAL COSTS: $287.72 ___________
7. NET RETURNS TO RISK AND MANAGEMENT: $230.28 ___________
3. Small Grain Variety Selection
Randy Weisz, Paul Murphy, and Christina Cowger
Keep Up to Date!
Small grain varieties generally have the highest
yields and milling quality during the first couple of
years after their release. Consequently, the varieties
grown on a farm should change over time. This
makes it important to keep up to date on newly
released varieties and how they are doing in NC.
Plant newer varieties on small acreage to assess
performance. Plant the most consistent performers
on most of the available cropland, and phase out
the older varieties showing signs of succumbing to
disease and insect pressures.
Getting Unbiased Information
The best source of unbiased public and private
wheat variety performance information for NC is
the Wheat Variety Performance and Recommendations
SmartGrains Newsletter (www.smallgrains.ncsu.edu/
_Misc/_VarietySelection.pdf), which is released
every July at NC State University and prepared by
Randy Weisz (in the Crop Science Department at
NC State) and Christina Cowger (USDA–
Agricultural Research Service, Plant Pathology
Department). This newsletter is based on the Official
Variety Test Report or OVT (www.ncovt.com), and
additional Cooperative Extension variety testing
projects around NC. This newsletter groups wheat
varieties into four categories: above average
yielding, above average but less consistently
yielding, average yielding, and below average
yielding. It also gives heading date and pest
resistance information about each wheat variety.
The best source of unbiased variety performance
information for other small grains is the OVT
(www.ncovt.com) produced annually by the Crop
Science Department at NC State University. It is
also updated every July.
Additionally, producers in counties adjacent to VA
may find the Virginia Official Variety Test Report to be
valuable (http://pubs.ext.vt.edu/category/
grains.html).
Guidelines for Specific Variety Selection
Avoid Varieties Not Adapted to North Carolina
All small grain varieties that have been in the OVT
for more than one year are usually good candidates
for production. Avoid investing in varieties that
have not been entered into these tests because they
usually are not adapted to NC’s growing conditions
and may be highly susceptible to local diseases or
mature too late to follow with double-cropped
soybeans. Only varieties that have been in the OVT
for at least two years are included in the Wheat
Variety Performance and Recommendations SmartGrains
Newsletter.
Plant at Least Three Varieties
Small grain variety performance can vary greatly
from one year to the next. This makes it nearly
impossible to pick a single best variety.
Consequently, producers should plant three or more
varieties every season. Growing at least three
varieties will reduce the risk of freeze injury, pest
damage, and other forms of crop failure and
maximize the potential for a high-yielding crop.
Pick High Yielding Varieties
Using the Wheat Variety Performance and
Recommendations SmartGrains Newsletter, the “Above
Average Yielding” varieties are good first choices.
The next to consider are the “Above Average but
Less Consistent Yielders.” These are varieties that
on average had high yield but are more risky.
Finally, the “Average Yielding Varieties” are likely to
Variety Selection 9
produce acceptable yields but may not win a yield
contest.
Avoid Spring Freeze Damage
Heading date is an important indication of how
susceptible a variety will be to late-spring freeze
damage. Early heading varieties are the most
susceptible to freeze damage, while late heading
varieties are the most likely to avoid yield loss due
to spring freezes. Figure 3-1 shows how different
varieties were damaged by the April 2007 freeze.
Early heading varieties (shown in solid red) were
severely damaged. Medium-early heading varieties
(striped red) also tended to be more severely
damaged. But late heading varieties (in black) were
barely damaged at all. In 2008, spring freeze damage
was observed at some locations and early and
medium-early varieties were again the most
damaged.
Heading date also indicates when a wheat variety
should ideally be planted. Medium and late heading
wheat varieties tend to do best when planted at the
start of the planting season, and consequently
should be the first varieties a producer plants. Early
and medium-early varieties tend to produce the
highest yields when planted later in the fall.
Barley is the earliest of the small grain species to
head, so it is at greatest risk of suffering spring
freeze damage and yield loss. In NC, the variety
Boone had been a long-time standard for barley
producers and rarely suffered late-spring freeze
damage. Current varieties such as Thoroughbred
and Dan have similar heading dates as compared to
10 Variety Selection
AGS 2000
SS 520
Pioneer 26R31
AGS 2000/USG 3209
Featherstone 176
SS 8404
Renwood 3260
USG 3209
AGS 2060
Coker 9511
USG 3342
Coker 9553
SS 560
Chesapeake
SS 8461
USG 3592
Coker 9312
Panola
NC Neuse/USG 3592
Tribute/Roane
SS 8308
USG 3910
SS MPV 57
Pioneer 26R12
Pioneer 26R24
Terral TV8558
USG 3665
Pioneer 26R15
SS 8302
SS 8309
NC Neuse
Coker 9436
Coker 9184
Roane
NC Neuse/Roane
0
10
20
30
40
50
60
70
Freeze Damage (%)
2007 Freeze Damage
Early Heading
Medium-Early Heading
Medium Heading
Late Heading
Figure 3-1. Damage caused by the April 2007 freeze for different wheat varieties. Early heading varieties
(shown in solid red) were severely damaged. Medium-early heading varieties (striped red) also tended to be
more severely damaged. But, late heading varieties (shown in black) were barely damaged at all.
Boone. So barley varieties that head earlier than
Thoroughbred or Dan should be viewed as having a
greater risk of yield reduction from freeze damage.
Tailor Variety Selection to Match the Most
Frequent Local Yield Robbing Factors
Variety selection is the best defense against most
pest problems encountered in NC. The three most
common foliar fungal small grain diseases are
powdery mildew, leaf rust, and Stagonosprora nodorum
blotch (Photo 3-1). Wheat varieties that are resistant
(or moderately resistant) to these diseases rarely
require a fungicide application. Two soilborne viral
diseases (soilborne wheat mosaic virus and wheat
spindle streak virus) are common in some areas, and
variety resistance is the only control method for
these diseases (Photo 3-2). Fusarium sp. head blight
or scab (Photo 3-2) can be problematic primarily in
years with warm, moist weather at heading, and
variety resistance is the best control method
producers have. In recent years, numerous wheat
fields have suffered losses due to Hessian fly (Photo
3-2). Wheat growers with a history of Hessian fly
problems should select Hessian fly-resistant
varieties.
Here are some fine-tuning guidelines:
• Central piedmont. The most common yield
robbers in this area include spring freeze damage,
barley yellow dwarf virus, and scab. Varieties that
are high yielding, late heading (to avoid freeze
damage), and resistant to these two diseases
would be ideal for the NC piedmont.
• Coastal plain. Powdery mildew, leaf rust, and
soilborne mosaic virus are common wheat pests
in the NC coastal plain. Ideal wheat varieties for
this region should be high yielding and have
resistance to all three of these diseases.
• Tidewater. Hessian fly and soilborne mosaic virus
have been frequent yield robbers in the NC
tidewater. Ideal wheat varieties are high yielding
and have resistance to soilborne diseases. Where
Hessian fly has been a problem, varieties with
resistance to it should also be selected.
High Test Weight Varieties
High test weight is usually associated with good
quality. A low test weight will result in dockage at
the elevator. Some varieties consistently have
superior test weight. Even a high test weight variety,
however, will produce a low test weight grain if
drought, potassium or sulfur deficiencies, fungal
diseases, lodging, or wet weather at harvest occur.
Coastal plain producers with deep sandy soils who
need high test weight grain should watch for
potassium and sulfur deficiencies.
Variety Selection 11
Photo 3-1. The three most common foliar fungal small grain diseases are powdery mildew (left), Stagonosprora nodorum blotch
(center), and leaf rust (right). Wheat varieties that are resistant (or moderately resistant) to these diseases rarely require a
fungicide application.
Lodging
Lodging is generally a greater problem in barley and
oats than in wheat. Under intensive management
practices, however, lodging will occur at a greater
frequency in all small grains. A lodged crop can
reduce test weight and slow combine operation.
Milling and Baking Quality of Wheat
Millers and bakers in NC use wheat for many
diverse products, and certain varieties are superior
to others for production of specific products.
Therefore, if you plan to grow wheat for sale
directly to a mill, discuss variety choice with the mill
quality-control staff. Just like test weight, even a
high-baking-quality variety can produce a low-quality
grain if nitrogen, potassium or sulfur
deficiencies, fungal diseases, lodging, or wet weather
at harvest occur.
Special Consideration for No-Till Variety
Selection
No-till producers should keep several additional
facts in mind when choosing varieties. Tillering and
fall growth are often slower in no-till small grains.
Consequently, no-till producers often achieve higher
yields if they plant during, or slightly ahead, of the
opening planting dates (see chapter 5, “Small Grain
Planting Dates” in this production guide:
www.smallgrains.ncsu.edu/_Pubs/PG/Pdates.pdf).
Planting early requires special care to select varieties
that (1) are “late” heading to avoid freeze damage,
(2) have “good” Hessian fly resistance to prevent
fall infestations (especially important in the NC
coastal plain and tidewater), (3) have at least
moderate resistance to barley yellow dwarf virus
(especially important in the NC piedmont), and (4)
have at least moderate resistance to powdery
mildew if planting in areas where powdery mildew
is common.
12 Variety Selection
Photo 3-2. Variety resistance is the best protection against Fusarium head scab (left). The only control method for soilborne
mosaic virus (center) is variety resistance. Producers with a history of Hessian fly (right) should grow resistant varieties.
4. To Plant or Drill: Does Row Spacing Matter?
Randy Weisz
Many growers have wondered if they could plant
wheat with the same implement they use to plant
narrow-row corn or soybeans. Does it make a
difference if wheat is drilled in 6- or 7.5-inch rows
compared to being planted in 15-inch rows? If it
does not make a difference, then the cost of
replacing a drill could be avoided.
We tested this idea in Salisbury in 2012, and
Andrew Gardner tested it in Union Couny in 2010
and 2011. Our results were similar to those
previously reported from other states. Figure 4-1
shows the results from winter wheat row-spacing
tests conducted at 35 locations across six states
(NC, VA, GA, PA, OH, and IN). As row spacing
increases, wheat yield declines. The lowest yields
were with 20-inch rows. Fifteen-inch rows had an
average yield (BLUE line, Figure 4-1) of 60.8
bushels per acre, 7.5-inch rows averaged 68.7
bushels per acre, and 4-inch rows averaged 76.1
bushels per acre. The difference between 7.5-inch
and 15-inch rows was 7.9 bushels per acre. If the
price of wheat is $7.50 per bushel, that comes to
$59.25 lost per acre by planting instead of drilling
wheat.
Does Row Spacing Matter? 13
50
60
70
80
90
2 4 6 8 10 12 14 16 18 20
Yield (bu/acre)
Row Spacing (inches)
All
VA - 3
GA - 2
IN - 4
OH - 8
NC - 3
PA - 15
Winter Wheat Row Spacing Studies
Test
Locations
Figure 4-1. Wheat yields at different row-spacings from studies conducted in NC, VA, GA, PA, OH, and IN.
Some data from: Beuerlein, LaFever. Applied Agric. Res. 4:47-50, and 4:106-110; Gardner. www.smallgrains.ncsu.edu/_Pubs/OnFarm/
Union2010.pdf, and www.smallgrains.ncsu.edu/_Pubs/OnFarm/Union2011.pdf; Joseph, Alley, Brann, Gravelle. Agron. J. 77:211-214; Johnson,
Hargrove, Moss. Agron. J. 80:164-166; Marshall, Ohm. Agron. J. 79:1027-1030, and Roth, Marshall, Hatley, Hill. Agron. J. 76:379-383.
5. Small Grain Planting Dates
Randy Weisz and Ron Heiniger
For producers of small grains, the goal is to select a planting date that gives an opportunity to develop as
many fall tillers as possible while avoiding potentially severe damage associated with fall insect and disease
infestations or an early spring freeze. Small grain tillers produced in the fall are most likely to have large
heads with kernels of high-test weight: the two components of a high-yielding crop. Fall tillers also tend to
have stronger root systems and consequently may be more stress resistant. The key advantage to planting
early in the fall is the opportunity to make the most of warmer temperatures. The warmer the weather, the
more tillers are likely to be produced. Cold temperatures impede growth, so it is important to plant small
grains while there is still enough time and mild weather for tillers to form before winter sets in. On the other
hand, planting too early can result in increased risk of diseases such as barley yellow dwarf virus and
powdery mildew, increased risk of Hessian fly infestations, and increased risk of spring freeze damage. The
same warm temperatures that enhance wheat growth also promote the development of insects and diseases
and shorten the period from emergence to flowering. At least one night below 32oF is required to reduce
Hessian fly or aphid populations and to slow disease development. Therefore, the selection of a planting
date for small grains is a balance between achieving good fall growth and avoiding severe damage.
Wheat
The traditional guideline for finding the right
compromise between planting early enough to
encourage tillering, but late enough to avoid insect
and disease problems, has been to plant wheat
within one week of the first frost. Figure 5-1 shows
starting dates for wheat planting in NC. The dates
shown in this map are one week earlier than the 30-
year average local freeze dates for weather stations
throughout NC. These dates mark the start of the
wheat planting season. In most parts of the NC
tidewater, coastal plain, and southern piedmont,
planting on these dates will allow wheat plants to
develop two to three additional large tillers by
February 1. That puts the crop in an excellent
position for high yield potential and reduces the
likelihood of needing to apply two applications of
N fertilizer in the spring. It also assures that some
cold weather will occur shortly after the seedlings
emerge to reduce disease and insect pest activity.
The dates shown in Figure 5-1, however, are often
when soybean, cotton, and (in some parts of NC)
peanut harvest is underway. This may force
producers to plant later. Planting wheat later than
the dates shown in Figure 5-1 can have a significant
impact on a crop’s yield potential. For example,
based on average NC weather records, planting 14
days later than the dates shown in Figure 5-1 usually
results in enough warm weather to produce only
one additional large tiller per plant by February 1 in
the NC tidewater and central to southern coastal
plain. In the rest of the state, not enough warm
weather may occur to get even a single additional
large tiller to develop by February 1. This makes it
very important to ensure that a late planted crop
was drilled in at higher seeding rates (see chapter 7,
“Small Grain Seeding Rates” in this production guide:
www.smallgrains.ncsu.edu/_Pubs/PG/Srates.pdf)
and to scout the wheat in late January to determine
if an early N fertilizer application will be required in
February to stimulate further tiller development in
the spring (see chapter 8, “Nitrogen Management for
Small Grains” in this production guide:
www.sm a l l g r a ins. n c s u . e du/_Pubs /PG/
Nitrogen.pdf).
Barley, Oats, Rye, and Triticale
Barley and oats should be planted about 5 to 10
days earlier than the dates shown for wheat in
14 Planting Dates
Figure 5-1. Rye planting dates are similar to those
for wheat. Triticale varieties that have been
developed for NC, like Arcia, can be planted on the
same dates as wheat. Trical triticale varieties that
have been tested in NC and shown to head at the
same time as wheat can also be planted on the same
dates shown in Figure 5-1. However, some triticale
varieties (such as Trical 498) are early heading, and
need to be planted late to avoid spring freeze
damage. It is important to know the maturity rating
for the triticale variety before selecting a planting
date.
Special Considerations for No-Till
Heavy residue left on the soil surface can reduce
soil temperatures. This results in slower germination
and tiller growth. Because fall growth can be
reduced in no-till, planting small grains early
becomes even more important. Establishing a
healthy, uniform stand by planting close to the dates
shown in Figure 5-1 may be a key to achieving high
yields in no-till. Some successful no-till producers
say they need to plant on or even a little earlier than
these dates (see chapter 6 “Beating Soybean Harvest: A
Very-Early-Wheat-Planting System” in this production
guide: www.smallgrains.ncsu.edu/_Pubs/PG/
VeryEarly.pdf).
Special Considerations for Hessian Fly
Hessian fly has become a serious wheat pest in NC.
Because Hessian fly adults are killed by freezing
temperatures, a traditional method for preventing
Hessian fly infestation is to delay planting until after
the first freeze (often called the fly-free date). The fly-free
date concept has not worked well in NC (see
chapter 11, “Insect Pest Management,” in this guide:
www.smallgrains.ncsu.edu/_Pubs/PG/Insects.pdf).
Often a “killing freeze” does not occur until
December in many areas of NC, after most growers
need to have wheat planted if they want to have
enough fall growth to produce high yields. Delayed
planting will only prevent Hessian fly infestations if
a freeze has occurred.
Planting Dates 15
Murphy
Asheville
Jefferson
Mt Airy
Mocksville
Salisbury
N. Wilkesboro
Hickory
Forest City Gastonia
Concord Albemarle
Monroe
Jackson
Springs
Reidsville Oxford Arcola
Siler City
Raleigh
Sanford Smithfield
Fayetteville
Laurinburg
Whiteville
Willmington
Longwood
Warsaw
GoldsboroKinston
Rocky Mt
Murfreesboro
Elizabeth
City
Plymouth
New
Holland
Bayboro
Morehead
City
Hofmann
Forest
Lumberton
Sept 25 - 30
Sept 30 - Oct 5
Oct 5 - 10
Oct 10 - 15
Oct 15 - 20
Oct 15 - 20
Oct 20 - 25
Oct 15 - 20
Oct 25 - 30
Oct 25 - 30
Oct 20 - 25
Oct 25 - 30
Oct 30 - Nov 4
Oct 30 - Nov 4
Oct 30 - Nov 4
Figure 5-1. The start of wheat planting dates. The dates shown on this map are 7 days earlier than the date when there is a 50%
chance of having a freeze.
6. Beating Soybean Harvest:
A Very Early Wheat-Planting System
Randy Weisz
Why Plant Before Soybean Harvest
In NC, the ideal dates for planting wheat (see Figure
5-1: www.smallgrains.ncsu.edu/_Pubs/PG/
Pdates.pdf) herald the beginning of soybean and
cotton harvest. Consequently, wheat planting is
often delayed until cold wet weather has set in, and
wheat development suffers. Research in Virginia
and NC has shown that up to 85 percent of the
yield in a any given wheat field is made up by grain
heads formed on tillers that developed in the warm
fall weather. When planting is delayed, there is less
time for fall tillers to develop and this results in
reduced yield potential. This is especially true for
no-till. Wheat planted no-till (especially in NC
coastal plain and tidewater soils) tends to grow and
tiller more slowly than when planted in
conventionally tilled seedbeds. Planting early is one
way to help no-till seedlings make up for this slower
growth and produce more fall tillers. It would be
ideal if wheat could be planted before the start of
soybean or cotton harvest to take full advantage of
the warm tiller-inducing fall weather.
Challenges and Solutions
I n c h a p t e r 5 , “ S m a l l Gr a i n P l a n t i n g
Dates” (www.smallgrains.ncsu.edu/_Pubs/PG/
Pdates.pdf), we stated that the ideal time to plant
wheat was within 7 to 10 days of the first freeze.
Planting earlier than that puts the crop at risk of
early season insect damage, including wireworm
(especially in no-till production in the NC coastal
plain), Hessian fly, and aphid feeding that can
spread barley yellow dwarf virus. One way to avoid
these problems is to use an insecticidal seed
treatment (such as GauchoXT or Cruiser/
Dividend). These seed treatments can give about 19
days of protection from these insects. A second
potential problem is too much fall tiller production
resulting in very thick stands that may lodge before
the end of winter. A good way to avoid this is to
reduce seeding rates. Finally, many growers will say
that they cannot plant too early because of the risk
of spring freeze damage. The earlier wheat is
planted, the earlier it heads out in the spring. Once
wheat has headed, it becomes freeze tender and can
lose yield if a freeze occurs. In NC most “early-heading”
wheat varieties head in the first week of
April. “Late-heading” varieties may head out one to
two weeks later. Consequently, if there is a freeze
the end of the first week in April, early-heading
varieties may be damaged while the late varieties
may escape.
Making It Work
There are five essential parts to the very early
wheat-planting system.
Planting 10 Days to Two Weeks Early
Plant 10 days to two weeks earlier than the dates
shown in Figure 5-1: www.smallgrains.ncsu.edu/
_Pubs/PG/Pdates.pdf. Because the seed treatments
used in this system only give limited protection,
planting should not be more than about 14 days
early. In the NC central piedmont (at Salisbury), we
have been planting between September 29 and
October 3. In the NC central coastal plain (at
Kinston), we have been planting from October 6
through October 8. In the NC tidewater at
Plymouth and Terra Ceia, we’ve planted between
October 8 and 11.
Plant Only Late-Heading Varieties
Late-heading varieties have the lowest risk of
damage from a spring freeze. These are the only
16 Very Early Planting
varieties that should be used in the very early
planting system. This system has been tested with
NC-Neuse and Roane (two late-heading wheat
varieties) for six years in Salisbury, and shown to
work well.
Always Use an Insecticidal Seed Treatment
Treating all seed with an insecticidal seed treatment
such as GauchoXT or Cruiser/Dividend is critically
important. In our very early planting trials in the
NC piedmont, using an insecticidal seed treatment
usually resulted in a 10-bushel-per-acre yield
advantage over untreated seed. In eastern NC, the
seed treatment is critical to prevent Hessian fly,
wireworm, and aphid infestations.
Plant at Reduced Seeding Rates
Early planting results in extra tiller development. To
avoid excessive growth, wheat is planted with one-third
less seed then normal (see chapter 7, “Small
Grain Seeding Rates For NC” in this production guide:
www.smallgrains.ncsu.edu/_Pubs/PG/Srates.pdf).
Restrict No-Tillage to the Piedmont
In the NC piedmont this system has worked well
with no-till planting. In the NC coastal plain and
tidewater, very early no-till planting is not
recommended. This is due to the slower growth
that young wheat plants exhibit when planted no-till
in eastern NC. This slower growth combined with
possible wireworm and Hessian fly damage can
reduce no-till yields even with the insecticidal seed
treatments. On the other hand, very early planting
in eastern NC has worked well with conventional
tillage.
Very-Early-Planted Variety Testing
Tests across NC have shown that when the five
steps outlined above are followed, wheat yields are
similar to those achieved when planting at the
normal recommended times shown in Figure 5-1:
(www.smallgrains.ncsu.edu/_Pubs/PG/Pdates.pdf)
using normal seeding rates (Tabl e 7-1:
www.smallgrains.ncsu.edu/_Pubs/PG/Srates.pdf)
and untreated seed. The very early planting even at
the lower seeding rates allows the wheat time to
tiller and often to produce a thicker stand than
would normally be achieved (Photo 6-1). Yield
results from trials conducted in Salisbury in 2009,
2010, 2011, and 2012 are shown in Table 6-1.
Very Early Planting 17
Photo 6-1. Even though the very-early-planting-system uses 30% less seed, it often results in denser stands due to greater tillering
in the fall. Left: The very-early-planting system at Plymouth, NC, planted on October 8, 2009. Right: Normal wheat planting
system also at Plymouth, planted on October 29, 2009. The photographs were taken on February 17, 2010.
Table 6-1. Very-early-planting variety test results from Salisbury, NC. The tests were
planted on Sept. 29 using reduced seeding rates, GauchoXT, and only late-heading
varieties.
Late-Heading
Wheat Varieties
Yield
(bu/acre)
2012 2011 2010 2009
Pioneer 26R20 109.0
DynaGro 9053 105.9
Pioneer 26R12 101.3 131.5 99.7 106.1
DynaGro Shirley 101.2 133.2 102.8
Branson 98.1 131.3
Pioneer 25R32 93.6 127.2
UniSouth Genetics 3665 91.2 133.5 92.2 102.4
AgriPro Coker 9436 91.1 130.3 86.9 85.5
VA Merl 90.6 133.2 92.9
Pioneer 26R15 90.6 82.4 99.0
Southern States 8302 90.4 132.6 97.1 102.6
ARS Appalachian White 66.6
DynaGro V9713 128.2 90.0 99.5
NC Yadkin 122.6
NC Neuse 118.4 87.5 86.4
UniSouth Genetics 3725 91.1
VA Roane 85.8 93.5
18 Very Early Planting
7. Small Grain Seeding Rates for North Carolina
Randy Weisz and Ron Heiniger
Wheat, Triticale, and Hulled Barley
The results from ten wheat seeding-rate studies
(conducted in Virginia and North Carolina) are
shown in Figure 7-1. In these studies certified seed
with a high germination rate was planted on
different sites at seeding rates ranging from about
0.6 million to over 2.0 million seeds per acre. All ten
tests were planted using conventional tillage near
the recommended dates shown in Figure 7-2 for
North Carolina. In Figure 7-1 yield is shown relative
to the highest yielding seeding rate in each test. So,
for each of the ten tests, the yield at the highest
seeding rate is set to 0.
As seeding rates range from 0.9 to 1.6 million seeds
per acre, average yield (blue line in Figure 7-1) only
varies by about 1 bushel per acre! The grey box in
Figure 7-1 shows a broad range in seeding rates (1.1
to 1.5 million seeds per acre) that produced the
highest average yields. As seeding rates drop below
that, yield becomes highly variable. In some years
when the fall weather was warm, these lower
seeding rates yielded well. In other years when the
weather did not favor rapid tillering, low seeding
rates resulted in up to a 12 bushel loss. Seeding rates
above 1.5 million seeds per acre generally resulted in
lower yields probably due to higher disease levels
and lodging.
Seeding Rates 19
Figure 7-1. Ten wheat seeding-rate studies conducted using certified seed with high germination (at
least 90 percent), planted into conventionally tilled seed beds and planted near the dates shown in
Figure 7-2. Yield is shown as a percent of that at the highest seeding rate. Seeding rates ranged from
0.6 to 2.3 million seeds per acre. The grey box represents suggested seeding rates based on these tests.
J J
J
J
J
J
J
J
J
J
J
J J
J
J
J
J
J
J
J
J
J
J
J
J J
J
J
J
J
J J
J
J
-14
-12
-10
-8
-6
-4
-2
0
2
4
6
8
0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3
Yield (bushels per acre from optimum)
Seeding Rate (million seeds per acre)
Timely Planted Yield
The grey area in Figure 7-1 shows an optimal range
in seeding rates from 1.1 to 1.5 million seeds per
acre. This range in seeding rates is similar to what
other researchers have found. For example,
Syngenta Seed has been doing wheat seeding-rate
studies in the NC coastal plain. They report that
optimum yields are frequently reached for most
growers at around 1.1 million seeds per acre. They
recommend 1.5 million seeds per acre for growers
interested in intensive management. The intensive
wheat management guide from the Virginia
Polytechnic Institute recommends planting 1.31 to
1.52 million seeds per acre.
Many growers think about small grain seeding rates
in terms of pounds of seed per acre. Table 7-1
shows how 1.31 and 1.52 million seeds per acre can
be converted into more familiar units. The lower
rate of 1.31 million seeds per acre is equal to 30
seeds per square foot. The higher rate (1.52 million
seeds per acre) is the same as 35 seeds per square
foot. But, the number of pounds of seed needed to
reach these targets depends on seed size. A large
seeded variety may only have 10,000 seeds per
pound compared to a small seeded variety that
could have up to 15,000 seeds in a pound. This
makes planting a single number of pounds of seed
per acre problematic. Table 7-1 shows that the ideal
seeding rate of 1.31 to 1.52 million seeds per acre
can range all the way from 87 to 152 pounds of
seed per acre depending on seed size! It is
important that growers consider seed size when
selecting seeding rates based on pounds per acre!
Most drills have tables that indicate how to set the
seed metering mechanism for a given seeding rate in
pounds per acre. Ideally, if the seed size is known
(for certified seed it is often printed on the tag
attached to the bag), a grower could use Table 7-1
to determine the pounds of seed to plant per acre,
and use the drill manufacturer’s information to find
the proper drill setting to plant that number of
pounds per acre. However, experience has shown
that using these factory settings can result in large
over- or under-seeding. For example, in 2001 we
calibrated a John Deere no-till drill to plant the
correct seeding rate (based on Table 7-1) for 15
wheat varieties, each of which had half the seeds
treated with GauchoXT seed treatment and half
untreated. To produce the same seeding rate for
each variety, we had to change the drill setting from
27 all the way to 45—depending on the variety and
20 Seeding Rates
Murphy
Asheville
Jefferson
Mt Airy
Mocksville
Salisbury
N. Wilkesboro
Hickory
Forest City Gastonia
Concord Albemarle
Monroe
Jackson
Springs
Reidsville Oxford Arcola
Siler City
Raleigh
Sanford Smithfield
Fayetteville
Laurinburg
Whiteville
Willmington
Longwood
Warsaw
GoldsboroKinston
Rocky Mt
Murfreesboro
Elizabeth
City
Plymouth
New
Holland
Bayboro
Morehead
City
Hofmann
Forest
Lumberton
Sept 25 - 30
Sept 30 - Oct 5
Oct 5 - 10
Oct 10 - 15
Oct 15 - 20
Oct 15 - 20
Oct 20 - 25
Oct 15 - 20
Oct 25 - 30
Oct 25 - 30
Oct 20 - 25
Oct 25 - 30
Oct 30 - Nov 4
Oct 30 - Nov 4
Oct 30 - Nov 4
Figure 7-2. The start of wheat and triticale planting dates for NC. Timely planting for oats and barley is five to ten days earlier.
seed treatment! Our experiment revealed that the
drill settings required to achieve the correct wheat-plant
population varied widely among varieties and
seed treatments and this variation was not reflected
in the manufacturer’s charts.
The best way to ensure a correct small grain seeding
rate is to calibrate the drill for the specific seed
being planted. The most accurate way to calibrate is
to base seeding rates on the desired number of seed
per drill-row foot. This number does not vary
across seed sizes or change depending upon seed
treatments. Table 7-1 gives target seeding rates in
terms of seeds per drill-row foot across a range of
drill-row widths. For example, Table 7-1 shows that
if a grower has a drill with 7.5-inch row spacing, the
correct seeding rate is between 19 and 22 seeds per
drill-row foot (assuming planting is on time, the
seed has at least 90 percent germination, and
planting is into a conventionally tilled seed bed).
Hulless Barley
Hulless barley seed is more easily damaged then
hulled seed. Consequently, hulless barley must be
planted at higher seeding rates than traditional
hulled varieties. Dr. Wade Thomason, the corn and
small grain specialist at Virginia Tech, gives this
guideline: When using high-quality hulless barley
seed with at least 90 percent germination, the target
seeding rate is 2.2 million seeds per acre or 50 seeds
per square foot when using a conventionally tilled
seedbed. Table 7-2 gives hulless barley seeding rates
across a range of seed sizes and drill row widths.
Seeding Rates 21
Table 7-1. Wheat, triticale, and hulled barley seeding rates
for conventionally tilled seed beds planted on time using a
target of 1.31 to 1.52 million seeds per acre with 90
percent germination as a standard. These rates need to be
increased by 20 percent for no-till.
Million seeds per acre: 1.31 1.52
Seeds per square foot: 30 35
Seed size
(seeds per pound)
Pounds of seed
per acre
10,000 131 152
11,000 119 138
12,000 109 127
12,500 105 122
13,000 101 117
14,000 94 109
15,000 87 101
Drill row spacing
(inches)
Seed
per drill-row foot
6 15 17
7 18 20
7.5 19 22
8 20 23
Table 7-2. Hulless barley seeding rates for conventionally
tilled seed beds using a target of 2.2 million seeds per acre or
50 seeds per square foot with 90 percent germination as a
standard assuming planting is on time. These rates need to
be increased by 20 percent for no-till.
Million seeds per acre: 2.2
Seeds per square foot: 50
Seed size
(seeds per pound)
Pounds of seed
per acre
10,000 218
11,000 198
12,000 182
12,500 174
13,000 168
14,000 156
15,000 145
Drill row spacing
(inches)
Seed
per drill-row foot
6 25
7 29
7.5 31
8 33
Oats and Rye
Oats should be planted at 2 bushels per acre. Rye
should be planted at 1 to 1.5 bushels per acre.
Low Germ Seed
The seeding rates shown in Tables 7-1 and 7-2 are
for seed with at least 90 percent germination. Some
certified seed, and most bin-run seed, will not have
germination rates this high. Consequently, the
seeding rates in these tables need to be increased for
seeds with a germination rate lower than 90 percent.
Table 7-3 shows the increase required for different
levels of germination.
Low Germ Seed Example
If a grower wants to plant wheat at the higher
seeding rate of 1.52 million seeds per acre and has a
variety with 12,500 seeds per pound, Table 7-1
indicates the recommended seeding rate would be
122 pounds of high germ seed per acre. A germ
test indicates the seed has a germination rate of
only 80 percent. Table 7-3 shows the seeding rate
will have to be increased by 13 percent to
compensate. Thirteen percent of 122 pounds is 16
pounds. So the grower would plant 122 + 16 = 138
pounds of this seed with lower germ.
What About Planting Late?
In NC, small grains frequently follow soybeans that
are harvested in October or November. This results
in small grains being planted after the optimal
planting dates. When wheat, triticale, hulled or
hulless barley is planted after the dates shown in
Figure 7-2, seeding rates should be increased by 4 to
5 percent for each week planting is delayed.
Planting Depth
Wheat varieties have semidwarf genes that reduce
overall plant height. These also reduce the chances
of seedling emergence if the seeds are placed too
deep. Conversely, a shallow planting can result in
uneven germination due to dry soil. Small grain
seeds should be planted 1 to 1.5 inches deep when
soil moisture levels are adequate and slightly deeper
if moisture is deficient.
Seeding Rates for No-Till
No-till planting causes special challenges related to
uneven seed beds and surface residue. Although
seeds should still be planted 1 to 1.5 inches below
the soil surface, be aware that changes in the depth
of any residue and undulations in the soil’s surface
may result in the drill missing the targeted seeding
depth. When residue from the previous crop is
unevenly distributed, achieving a uniform and
correct planting depth can be difficult. Where the
residue is uneven, the planting depth may be too
shallow under high residue and too deep in areas of
light residue. This can result in thin stands and
excessive risk of winterkill. Preparation for no-till
small grains begins with evenly distributing crop
residues while harvesting the previous crop.
To obtain a uniform stand, start with a seeding rate
that is 20 percent higher than what is recommended
for conventional tillage (Tables 7-1 and 7-2). When
no-till drilling, stop periodically and make sure that
the planting depth is uniform and correct.
22 Seeding Rates
Table 7-3. Increase in seeding rates required for lower
germination seed.
Seed germination Increase seeding rates in
Tables 7-1 and 7-2 by:
85% 6%
80% 13%
75% 20%
70% 29%
65% 38%
Drill Calibration
The manufacturer’s seeding rate chart that comes
with commercial drills is a rough estimate of how
many pounds of seed will be planted at a given
setting. Experience with wheat seed has shown that
this estimate can be off by as much as 100%. The
best way to be sure the correct seeding rate is being
planted is to calibrate the drill for each seed lot
being grown.
Three methods for calibrating a drill are
d e m o n s t r a t e d i n a n o n l i n e v i d e o at
www.smallgrains.ncsu.edu/drill-calibration.html.
The simplest drill calibration method is outlined
below:
1. Select the desired seeding rate. For example, if
planting on-time, using conventional tillage, and
high quality seed, a recommended wheat seeding
rate would be 1.3 million seeds per acre.
2. Use Table 7-1 to convert seeds per acre to seeds
per drill row foot. For example, if planting at 1.3
million seeds per acre with a drill that has 7.5-
inch row spacing, Table 7-1 indicates that
converts to 19 seeds per foot of row.
3. Hook a tractor to the drill, put at least several
inches of seed in the hopper, and use the setting
that is a “best guess” at what is needed to get the
correct seeding rate.
4. Run the drill for 20 to 30 feet over firm ground
(like a dirt road) with minimum down pressure on
the openers and closing wheels so that the seed is
exposed and easy to see.
5. Pick a drill row and count the number of seed in
two feet.
6. If there are too many seed, lower the setting and
try again. If there are too few seed, increase the
setting and repeat. For example, if the target is 19
seed per drill row foot, but the drill dropped 24,
the setting needs to be reduced.
7. Repeat step 6 until the number of seed being
dropped is correct. Record the setting needed for
this seed lot.
Special Considerations for Broadcast
Seeding
Broadcast seeding often results in uneven seed
placement in the soil, which results in uneven
emergence and stands. Seeds may be placed as deep
as 3 to 4 inches, where many seeds will germinate
but will not emerge through the soil surface. Other
seeds may be placed very shallow or on the soil
surface. These seeds often do not survive due to dry
soil or winter damage. The uneven stands from
broadcasting often result in lower yields compared
with drilling. One method of improving stand
uniformity is to broadcast seed in two passes across
the field using half the seeding rate for each pass.
The second pass is made perpendicular to the first
pass. Although this method should improve stand
uniformity, it also increases the time required to
seed the field. Because plant establishment potential
is reduced and seed placement is not uniform,
seeding rates should be increased for broadcast
seeding. Increase broadcast seeding rates by 30
percent to 35 percent over drilled seeding rates.
Seeding Rates 23
Online VIDEO:
How to Calibrate a Drill
www.smallgrains.ncsu.edu/drill-calibration.html
Broadcasting wheat with fertilizer is a fast way to
seed small grains. Take precautions to ensure that
the seed is uniformly blended with the fertilizer and
that the fertilizer-seed mixture is uniformly applied.
Seed should be mixed with fertilizer as close to the
time of application as possible and applied
immediately after blending. Allowing the fertilizer-seed
mixture to sit after blending (longer than 8
hours), particularly with triple super phosphate
(0-46-0) or diammonium phosphate (18-46-0),
results in seed damage (reduced germination) and,
subsequently, a poor stand.
Considerations for Overseeding
Small grains may be planted by overseeding in
standing, unharvested crops. To follow soybeans,
seed as the first soybean leaves begin to drop.
Following cotton, seed just before defoliation. The
small grain can be injured or killed if it is growing
when a desiccant is used. If no desiccant is used,
seed when the leaves begin to drop. The leaves will
form a mulch that conserves moisture and enhances
germination.
The success or failure of overseeding depends on
available moisture. Overseeding before a rainfall
event improves the chances of success. Wheat and
rye tend to emerge better when overseeded than do
oats or barley.
Test the Results: Check the Stands
No matter how you plant the seed, be sure to check
the stands shortly after emergence. Is the stand
uniform? Determine the number of healthy
seedlings present in a square foot. There should be
22 to 25 seedlings (or more, if planted late). If the
stand is uniform and the plant density is correct,
then the planting was successful.
References
Some materials in this chapter were adapted from:
Alley, Brann, Stromberg, Hagood, Herbert, Jones. 1993. Intensive Soft
Red Winter Wheat: A Management Guide (Publication 424-803).
Virginia Polytechnic Institute, Cooperative Extension Service.
Ambrose. 1998. Wheat On-Farm-Test Report. Beaufort County
Cooperative Extension Service & NC State University.
(www.smallgrains.ncsu.edu/_Pubs/OnFarm/BFT1998.pdf).
Ambrose. 1999, 2000, & 2001. Wheat On-Farm-Test Report. Beaufort
County Cooperative Extension Service & NC State University.
Joseph, Alley, Brann, Gravelle. 1985. Row Spacing and Seeding Rate
Effect on Yield and Yield Components of Soft Red Winter
Wheat. Agron. J. 77:211-214.
Lee, Herbek. 2009. A Comprehensive Guide to Wheat Management in
Kentucky (Publication ID-125). Lexington, KY: University of
Kentucky College of Agriculture, Cooperative Extension
Service.
Smith, Wood, Grandy, Williams, Smith, Powell. 2006. NE Expo Wheat
Field Day Test Results. Perquimans, Pasquotank, Currituck,
Chowan, Gates, and Camden County Cooperative Extension
Service & NC State University. (www.smallgrains.ncsu.edu/
_Pubs/OnFarm/NEX2006.pdf)
Weisz, Love, Tarleton. 2011. Southern Coastal Plains Small Grains
Extension Program 2011 Test Report. NC State University.
(www.smallgrains.ncsu.edu/_Pubs/OnFarm/SCNC2011.pdf)
Weisz, Love, Tarleton. 2012. Southern Coastal Plains Small Grains
Extension Program 2012 Test Report. NC State University.
(www.smallgrains.ncsu.edu/_Pubs/OnFarm/SCNC2012.pdf)
24 Seeding Rates
8. Nitrogen Management for Small Grains
Randy Weisz and Ron Heiniger
Nitrogen management is one of the most important keys to successful small grain production. It is also one
of the easiest management strategies to misuse, resulting in yield reductions and environmental damage. To
achieve optimum yields, follow the correct N guidelines for applications in the fall, winter, late January to
early February, and at growth stage 30 (which usually occurs in March). Chapter 9, “Nutrient Management for
Small Grains” (www.smallgrains.ncsu.edu/_Pubs/PG/Nutrient.pdf), discusses soil testing and management
of all other nutrients. We discuss N management first and separately because there is no soil test useful for
making N recommendations in NC, and because of its importance for small grain production.
Fall: Preplant Nitrogen
When Planting Near the Recommended Dates
When planting on time, 15 to 30 pounds preplant N
per acre are generally sufficient to promote
maximum growth and tillering. This application can
be very important for high yields because N stress
early in the season will prevent adequate tillering.
When small grains follow soybeans or peanuts,
enough carryover N may be present to meet small
grain fall requirements. Unfortunately, the
availability of carryover N is difficult to predict and
there is no method for testing for available N in the
fall. In many years and locations, the N released
from a previous legume crop many not be available
until the following spring or even summer, which is
too late to support fall tillering. Consequently,
unless experience with specific fields indicates
otherwise, a small amount of preplant N is
recommended even when following soybeans or
peanuts.
When Planting Later Than Recommended
Research has shown that late-planted small grains
may not respond to preplant N applications. When
temperatures are too low to promote tillering,
preplant N cannot be taken up by the plants and is
easily leached out of the soil. Adding preplant N
even at high rates cannot simulate tillering in cold
soils. Consequently, when planting late, application
of preplant N to small grains might be skipped.
Early Planting System
In chapter 6, “Beating Soybean Harvest: A Very Early
W he a t - P l a n t i n g S y s t em” ( o n l i n e a t :
www.sm a l l g r a ins. n c s u . e du/_Pubs /PG/
VeryEarly.pdf), we introduced a system for very
early wheat planting. Small grains planted before
the optimal planting dates risk freeze damage. So
when planting very early, it is important to follow all
the recommendations given in that chapter.
Additionally, preplant N application to early planted
small grains promotes increased tillering, but this
can also increase the risk of freeze damage. While
applying N to early planted small grains will often
result in better looking stands, research has shown
that it generally does not increase yields.
Consequently, preplant N should be reduced or
eliminated when planting earlier than the
recommended dates (see chapter 5, "Small Grain
Planting Dates, in this production guide:
www.smallgrains.ncsu.edu/_Pubs/PG/Pdates.pdf).
No-Till
Preplant N management for no-till small grains is
similar to conventional-till with a couple of minor
differences. Many no-till growers find that their pre-plant
N rates need to be on the high end of the
recommended range. Therefore, when planting
during the recommended planting dates, consider as
much as 30 lbs of preplant N per acre. Growers
using the early planting system may also want to
Nitrogen Management 25
consider applying 15 to 30 lb N per acre preplant,
particularly in conditions where corn or sorghum
residue is heavy.
Winter: Rescue Applications
Nitrogen management during the winter consists of
making sure the crop does not become N deficient.
Small grains under N stress in the winter can lose
tillers, which may reduce yield. Indications of a
possible N deficiency are a pale green color, thin
and poorly developing stands, and leaching rains
after planting. An application of 15 to 30 pounds N
per acre can help to green the crop back up if these
symptoms occur. This rescue application needs to
be made when daytime temperatures are expected
to be above 50oF.
Late January and Early February: Last
Chance to Grow More Tillers
Late January to early February is the time to
determine if the crop has enough tillers to optimize
yield. This is a very important decision. Apply N in
January or February only if tiller densities are less
than 50 tillers per square foot. If N is not needed,
applying N in January or February results in
increased risk of freeze damage, disease, lodging,
and reduced yield. If tillering is low, however, an
early application of N can help to stimulate further
tiller development in the last few weeks before
growth stage 30, resulting in higher yield and profit.
The following guidelines will help you decide
whether to apply N in late January or early
February.
Guidelines for Wheat
If at the end of January or in the first week of
February, wheat looks as thick as that shown in
Photo 8-1, it is well on the way to being a
potentially high yielding field. This wheat has about
100 well-developed tillers per square foot and
should not have any N applied until growth stage
30. A well-developed tiller is one with at least
three leaves.
The wheat in Photo 8-2 is a “medium” density
stand with about 50 tillers per square foot. It also is
well on the way to being a good yielding crop, and
should not have any N applied until growth stage
30. The wheat in Photo 8-3, however, is poorly
tillered and only has about 20 tillers per square foot.
It has a low yield potential and needs more tillers to
develop in February. It should have 50 to 70 pounds
N fertilizer applied in late January or early February.
A second N application should be made to finish
this crop off at growth stage 30. Thin stands like
those shown in Photo 8-3 need timely weed
management, but should not have 2,4-D applied
because 2,4-D may inhibit tiller development.
Growers also need to scout for cereal leaf beetle in
April, as these insect pests are often attracted to
thin wheat stands.
Wheat stands that are thicker than the stand shown
in Photo 8-3 but not as well developed as that
shown in Photo 8-2 also need an early N
application. Such a field will yield best with 40 to 50
pounds of N fertilizer applied in late January or
early February and a second N application to finish
the crop off at growth stage 30.
This approach to stand evaluation is shown in
Figure 8-1. In late January and early February, a
“tiller” is considered to be any stem that has three
or more leaves. Rough estimates of tiller density can
26 Nitrogen Management
Online VIDEO:
Counting Tillers to Optimize N Rates
www.smallgrains.ncsu.edu/tiller-counting.html
be made by comparing a wheat field with Photos
8-1 through 8-3, or more exactly by counting tillers.
To determine tiller density, count well-developed
tillers (those with at least three leaves). Ignore small
tillers that have only one or two leaves. Do not be
concerned with differences between the main plant
and younger side tillers. Just count any stem with at
least three leaves as a tiller. The final count will
include main plants, tillers, and side tillers. Count all
the tillers that have at least three leaves in a yard of
row. Do this in several places and take an average.
Tiller density is then computed as follows:
Tillers per square foot =
(tillers per yard of row) × 4
(row width in inches)
Example: If in five counts of tillers in a
yard of row the average was found to be
102 tillers per row and the row spacing is
7.5 inches, then tiller density is:
102 × 4 ÷ 7.5 = 54.4 tillers per square foot.
An alternative is to mark out a square foot of
ground and count all the tillers in that area that have
at least three leaves. Do this in several places and
calculate the average.
Guidelines for Oats, Barley, Triticale, and Rye
Research on counting tillers to time N applications
for these crops has not been done. Growers will
need to rely on past experience to judge when
splitting N will benefit oat, barley, or triticale stands
that are thin in late January to early February.
Growth Stage 30: The Most Important
Time to Apply Nitrogen!
During growth stage 30, small grains switch from
producing tillers, to starting reproductive growth. In
the first phase of reproductive growth, the stem
elongates, the plant gets taller, and the small grain
crop begins to take up large amounts of N. The
Nitrogen Management 27
Photo 8-1. Well-tillered – about 100 tillers per square foot.
Photo 8-2. Medium-tillered – about 50 tillers per square foot.
Photo 8-3. Poorly-tillered – about 20 tillers per square foot.
Apply 50 - 70 lb N
as soon as possible
Does the wheat have at
least 50 tillers per square
foot ? (see Photo 8-2)
YES
NO
NO
YES
Is the wheat very thin
with only 20 to 30 tillers
per square foot ?
(see Photo 8-3)
Do not apply N until
growth stage 30
Apply 40 - 50 lb N
as soon as possible
Figure 8-1. Late January to early February guidelines for wheat
N fertilization.
future grain head is formed at this stage (although
still underground), and N stress at this growth stage
will affect head formation and result in smaller
heads. Since N at this stage of development is
critical and larger amounts of N are needed to
satisfy N requirements, the bulk of spring N
fertilizer needs to be applied at this stage. A typical
fertilizer application rate at growth stage 30 for
wheat is 80 to 120 pounds N per acre (minus any
that was applied in late January or early February to
stimulate tillering). However, optimal N rates can
vary dramatically from field to field and year to year
depending on the weather, the crop’s yield potential,
and the presence of carry-over N from previous
crops. Tissue testing at growth stage 30 is one way
to help fine-tune N rates to maximize economic
return.
The Wheat Tissue Test
Tissue testing for wheat N rate recommendations
was developed in VA and has been available for
many years. It uses the N concentration detected in
a tissue sample collected at growth stage 30.
Research in NC, however, has shown that the VA
recommendations can overestimate the required N
for our growing conditions. Therefore, a new
system has been developed that is helpful in
optimizing wheat N fertilizer rates specifically for
NC producers. This research indicates that N rates
based on a tissue test are most reliable for wheat
grown on well-drained soils. The test should not be
used on poorly-drained organic soils. This new
system and subsequent recommendations are
especially helpful when N prices are high and
growers need to minimize input costs without
compromising yield. For assistance with growth
stage 30 tissue testing, NC producers can contact an
NC Department of Agriculture & Consumer
Ser vices (NCDA&CS) r egional agr onomi st
(www.ncagr.gov/agronomi/rahome.htm) or county
Extension agent (www.ces.ncsu.edu). Here are the
steps and information needed to determine the
optimum N rate with a tissue test.
Step 1: Determine the Growth Stage
As temperatures warm in spring, tillering stops and
the wheat crop’s demand for N increases rapidly.
This is the beginning of stem elongation, often
referred to as growth stage 30. Because growth
stage 30 is the best time to apply N fertilizer to
winter wheat, it is important to know when the crop
reaches this stage. The calendar date when wheat
reaches growth stage 30 is influenced by variety,
planting date, and environmental conditions. Early-heading
varieties can reach it in February. Late-heading
varieties may not reach growth stage 30
until mid-March. One clue that the wheat is at
growth stage 30 is that the plants start to stand up
and get taller. However, the best way to tell if wheat
is at growth stage 30 is to pull up several plants and
split the stems down their centers all the way to the
base where the roots grow. Prior to growth stage 30,
the growing point will be at the very bottom of the
stem just above the first roots. At growth stage 30,
the growing point will have moved ½-inch up the
stem (Figure 8-2). After growth stage 30, it will
move further up the stem and be above the soil
surface. Tissue samples can be taken when the
28 Nitrogen Management
Growing
Point
First
Roots
Figure 8-2. Wheat stem cross-section at growth stage 30. The
growing point will be dark green, about 1/8-inch long, look
like a tiny pine cone, and prior to growth stage 30 be at the
very base of the stem next to the first roots. At growth stage
30 it will have moved 1/2-inch up the stem.
growing point is between ¼- and ¾-inch above the
base of the stem.
Step 2: Collect Tissue and Biomass Samples
Two pieces of information are needed to determine
the optimum N rate: percentage of tissue N and
biomass. At growth stage 30, take a tissue sample by
cutting wheat plants from 20 to 30 representative
areas in the field. The plants should be cut ½-inch
above the ground. Soil and dead leaf tissue must be
removed and the cuttings placed in a paper bag
labeled “tissue.” The percentage of N is detected in
this tissue sample. For the most accurate N rate
recommendation, an estimate of above-ground
biomass is also required. At one representative
location in the field, cut all the wheat along a 36-
inch section of row, remove any soil and weed
tissue, and place the entire sample in a second paper
bag labeled “biomass.” The biomass or weight is
detected in this sample. The two samples should be
shipped to the NCDA&CS Agronomic Division
immediately. If samples have to be stored for more
than 24 hours after collection, they must be dried to
prevent spoilage and loss of biomass.
Step 3: Use the Chart and Table with the Plant Report
An example of the NCDA&CS plant report is
shown in Figure 8-3. In this example, the dry weight
of the biomass cut from the 36-inch length of row
was 36 grams and the tissue N percentage was 3.5.
Using the biomass dry weight and the N percentage
values, N fer tilizer recommendations are
determined using either the BLUE, RED or
GREEN line in Figure 8-4. Low biomass wheat
fields use the BLUE line. Medium biomass fields
use the RED line. High biomass fields use the
GREEN line. To determine which line to use,
consult Table 8-1. Find the biomass value on the left
side of Table 8-1. Look across the table to find the
drill row spacing used in the field. The intersection of
the correct drill-row column and the dry-weight row
indicates which colored line to use. If the drill row
spacing in the SHOP field (Figure 8-3) is 6 inches,
then Table 8-1 indicates the GREEN line should be
used to get a N fertilizer rate recommendation.
If the wheat was broadcast seeded, there will be no
drill rows to sample and Table 8-1 cannot be used.
In broadcast fields, the biomass dry weight in a
square yard will need to be estimated. Low biomass
fields are defined as those with less than 84 grams
of dry biomass per square yard. Medium biomass
Nitrogen Management 29
Figure 8-3: NCDA&CS
Plant Analysis Report.
Table 8-1. Line color to use in Figure 8-4 for N rate
recommendations.
Dry weight
in 36 inches
of row (g)
Row spacing in inches
5 6 7 8
≤ 10
15
20
25
30
35
≥ 40
fields are defined as those with 84 to 157 grams dry
weight per square yard. High biomass fields have
more than 167 grams dry weight per square yard.
Step 4: Don’t Let a Sulfur or Potassium Deficiency Rob
Wheat Yield Potential
Sulfur-deficient wheat does not assimilate N
fertilizer efficiently so it is important to make sure
adequate sulfur (S) is available at growth stage 30.
In addition to the percent N content, the
NCDA&CS plant report also gives levels of other
plant nutrients, including S. These levels can be
checked against the critical values shown in Table
8-2. A tissue S content less than 0.25 percent, or an
N-to-S ratio greater than 15, indicates that S is
limiting and the wheat will likely benefit from an
application of 20 to 30 lb S per acre at growth stage
30.
North Carolina coastal plain wheat producers who
have deep sandy soils can also use the growth stage
30 tissue test to optimize potassium (K) fertilizer
inputs. This is especially important for producers
who may have skipped or reduced preplant potash
for their wheat and for the following double-cropped
soybeans. Ideally, growers who have wheat
on deep sandy soils should submit both a growth
stage 30 tissue sample and a diagnostic soil sample
from the same field. Tissue K levels of less than 2
percent indicate that the wheat crop is deficient. If
the soil sample also shows low K-index levels, K
will be needed as soon as possible for the wheat
crop, and certainly before the subsequent soybean
crop is planted.
Wheat Tissue Test Examples
Low Wheat Biomass Example
The plant report shows the biomass sample
weighed 8 grams and the tissue sample had a N
content of 3.5%. The wheat was planted in 6-inch
rows. Table 8-1 indicates the BLUE line in Figure
30 Nitrogen Management
0
10
20
30
40
50
60
70
80
90
100
110
120
2.0 2.5 3.0 3.5 4.0 4.5 5.0
GS-30 N Recommendation (lb/acre)
Percent N In Tissue At GS-30
N Recommendations For
Low biomass wheat
Medium biomass wheat
High biomass wheat
Virginia tissue test
Figure 8-4. Growth stage 30
N rate recommendations
based on the new NC wheat
tissue test.
Table 8-2. GS-30 whole plant tissue sample nutrient
sufficiency levels.
Nutrient
P K Mg S B Zn Mn Cu
------ % ------ ------ ppm ------
Sufficient
level 0.25 2 0.1 0.25 3 12 20 3
8-4 is the correct one to use as this is a low biomass
wheat field. Finding 3.5% on the horizontal axis of
Figure 8-4 and using the BLUE line show the
recommended N fertilizer rate is 71 lb per acre.
Thin wheat fields could result from late planting or
from fall temperatures that were too low to
promote tillering and growth. In fields like this, the
VA (dashed line) and NC system (BLUE line) make
very similar N rate recommendations.
Medium Wheat Biomass Example
The plant report shows the biomass sample
weighed 25 grams and the tissue sample had a N
content of 3.5%. The wheat was planted in 7-inch
rows. Table 8-1 indicates the RED line in Figure 8-4
is correct for N fertilizer rate recommendations as
this is a medium biomass wheat field. Finding 3.5%
on the horizontal axis of Figure 8-4 and using the
RED line show the recommended N fertilizer rate
is 46 lb per acre. In medium biomass fields, the VA
system (dashed line) tends to overestimate the N
fertilizer rate required to optimize yield and
economic return, especially for wheat with N
content greater than 3.5%.
High Wheat Biomass Example
The plant report shows the biomass sample
weighed 36 grams and the tissue sample had a N
content of 3.5%. The wheat was planted in 7-inch
rows. Table 8-1 indicates the GREEN line in Figure
8-4 is correct for N fertilizer rate recommendations
as this is a high biomass wheat field. Finding 3.5%
on the horizontal axis of Figure 8-4 and using the
GREEN line show the recommended N fertilizer
rate to be 0 lb per acre. High biomass fields can
result from high carry-over N from a previous crop,
fall manure application, or unusually warm fall and
winter weather that promoted excess tillering. In
these fields, the VA system (dashed line)
overestimates the growth stage 30 nitrogen fertilizer
rate.
Oats, Barley, Triticale, and Rye
Research on using tissue samples to optimize N
requirements for these crops has not been done.
Use Table 8-3 to determine the crop's total spring
N requirement.
Nitrogen Management 31
Table 8-3. Spring N recommendations for oats, barley,
triticale, and rye.
Region
Spring N Fertilizer
(pounds per acre)
Oats Barley Triticale Rye
Coastal Plains 100 100 120 80
Piedmont &
Mountains 80-100 80 120 80
Tidewater 100 100 120 80
9. Nutrient Management for Small Grains
Carl Crozier, Ron Heiniger, and Randy Weisz
Routine Soil Testing to Prevent and
Manage Nutrient Deficiencies
Soil testing before planting is an essential
component of a small grain fertility management
program. Different fields can vary so widely in pH
and nutrient levels that it is impossible to predict
optimum application rates without soil test results.
It is much more economical to prevent yield losses
associated with nutrient deficiencies than to try to
correct them once visible symptoms appear.
Producers should sample each field once every two
to three years at the same time of the year,
preferably in the early fall. Often this is done before
a corn or cotton crop, which tends to be more
sensitive to applied nutrients than small grains.
However, if you suspect a nutrient problem, then
sample more frequently before a small grain crop
and use that information to adjust nutrient
applications. Sample boxes, information sheets, test
results, and recommendations are provided free of
charge by the Agronomic Division of the
NCDA&CS, and guidelines for soil testing
procedures can be found in another Extension
publication: SoilFacts: Careful Soil Sampling – The Key
To Reliable Soil Test Information (www.soil.ncsu.edu/
publications/Soilfacts/AG-439-30).
Diagnostic Soil Sampling and Plant
Tissue Analysis
When abnormal growth or plant color is observed,
it is often useful to obtain diagnostic samples to
determine if there is a nutrient deficiency. If
samples are collected to diagnose an observed
problem rather than for routine purposes, then
separate samples should be submitted to represent
the surface soil (0 to 4 inches) and the subsoil (4 to
8 inches). Tissue analysis can determine whether an
adequate amount of fertilizer has been applied or if
a particular nutrient is limiting crop growth. Plant
tissue analysis is particularly useful in determining a
crop’s need for mobile nutrients, such as nitrogen,
sulfur, and boron; and for diagnosis of deficiency
symptoms for manganese, copper, or zinc. To take a
tissue test, clip a handful of plants above the
ground with 8 to 10 samples collected from both
the problem area and a corresponding area of
normal growth. When taking diagnostic samples,
both soil samples and plant tissues from the
affected "bad" area and a nearby unaffected "good"
area should be submitted for analysis to the
NCDA&CS diagnostic laboratory.
Soil pH and Lime Recommendations
Proper pH is critical in obtaining good crop growth
and yield. Small grains grow best when the pH is
near the target level for each soil class. If pH is too
low, soluble aluminum and acidity can limit root
growth and nutrient uptake. If pH is too high,
micronutrients such as manganese, iron, copper,
and zinc can become unavailable. Stunted growth,
nutrient deficiency symptoms, and low yield are the
most common problems associated with soil pH
levels that are not maintained in the proper range.
Often nutrient deficiencies are the result of low or
high pH rather than a lack of adequate amounts of
the nutrient in the soil. Ideal soil pH levels vary
based on soil type. Target levels are 6.0 for mineral
soils, 5.5 for mineral organic soils, and 5.0 for
organic soils. When the soil pH is below these
targets, apply lime as early as possible in the
production year to allow time for neutralizing soil
acidity. Liming rates and the type of lime applied
cannot be determined based on soil pH alone; they
also depend on residual soil acidity, residual credit
for recently applied lime, and measurement of
available magnesium. For more information see
SoilFacts: Soil Acidity and Liming for Agricultural Soils
32 Nutrient Management
(www.soil.ncsu.edu/publications/Soilfacts/
AGW-439-50/SoilAcidity_12-3.pdf ).
Phosphorus Recommendations
Phosphorus (P) plays a key role in germination and
early plant growth, promotes winter hardiness,
stimulates the growth of the wheat kernel, and has
a role in determining when the plant reaches
maturity.
Phosphorus Deficiency Symptoms
Purpling of the leaf margins and bottom leaf
surfaces of the lower plant leaves and purpling of
the leaf sheaths at the stem’s base are symptoms of
P deficiency. Slow growth or stunting is another
sign of P deficiency. Phosphorus-deficient plants
are slow to mature, and green heads are often found
in spots in the field at harvest. Deficiency
symptoms are often found on waterlogged, cool
soils in late winter or early spring.
Phosphorus Fertilizer Rates
As noted previously, a good soil test is the best way
to determine fertilizer requirements. The following
P recommendations are made only as guidelines and
should not replace soil testing as the primary means
of determining crop nutrient needs.
A wheat crop yielding 40 bushels per acre typically
requires 40 pounds of P2O5 (25 pounds in the seed
and 15 pounds in the straw). Mineral soils, such as
those found in the NC coastal plain and piedmont,
bind P and prevent it from leaching. Heavy organic
soils do not bind P, resulting in a movement of P to
the lower soil horizons or to drainage waters. Soils
high in clay content, such as those found in the
piedmont, bind P very tightly, making it unavailable
to the crop. Consequently, both heavy organic soils
and soils high in clay content often test low in
available P even though high amounts of P fertilizer
are applied every year. Care must be taken on these
soils to apply P in a way that limits the interaction
between the P fertilizer and the soil. Because animal
wastes are high in P, soils where heavy applications
of animal waste have been applied will have high
levels of available P. Table 9-1 shows the
recommended rates for P fertilizer in the different
regions and major soil types of the state.
Phosphorus Placement and Timing
Phosphorus should be broadcast on the soil just
before planting. Growers farming heavy organic or
clay soils should limit the amount of soil-fertilizer
contact (and thus reduce nutrient binding), which
means little to no tillage should occur after a P
application.
Potassium Recommendations
Potassium (K) influences grain quality (including
test-weight) and oil content, prevents lodging, and
plays an important role in drought and disease
tolerance.
Potassium Deficiency Symptoms
The most common deficiency symptom for K in
small grains is stunted growth and early lodging.
Plants with a K deficiency will have low vigor, poor
drought or disease tolerance, and reduced kernel
size. Under severe K deficiency, the leaf tip and
margins on the lower leaves will bronze and
eventually turn yellow and die. Deficiency
symptoms are more likely on deep sandy soils or
soils that are waterlogged and compacted.
Potassium Fertilizer Rate
A wheat crop yielding 40 bushels per acre typically
requires 64 pounds of K2O (16 pounds in the seed
and 48 pounds in the straw). Because so much of
the K in the plant is in the straw, most of it will be
recycled in the soil. Most of the agricultural soils in
NC have adequate to high levels of available K. In
particular, soils where animal waste has been
applied will be high in available K. The exception to
this rule is that available K is low on sandy soils in
the NC coastal plain and tidewater. Sandy soils do
not bind K, so the K leaches below the root zone.
Nutrient Management 33
Potassium Placement and Timing
Potassium should be broadcast just prior to
planting. On sandy or very sandy soils with a high
leaching potential, K should be applied in two
applications, half at planting and the other half just
prior to growth stage 30 when N is applied. There
is no benefit to applying K to a growing crop after
growth stage 31.
34 Nutrient Management
Table 9-1. Critical macronutrients for small grain production.
Element
Common
deficiency
symptoms
Common fertilizer forms 1
Basis for
fertilizer
rate
Suggested rates per acre
if soil test data are not
available2
Notes
Phosphorus
(P)
Stunting,
purpling on
margins of
lower leaves or
on leaf sheaths,
delayed maturity
Granular monoammonium
phosphate (MAP, 11-52-0)
Granular diammonium
phosphate (DAP, 18-46-0)
Liquid ammonium phosphate
(10-34-0)
Soil test Coastal plain mineral soils:
0 to 30 lbs P2O5
Tidewater organic soils low
P index:
30 to 50 lbs P2O5
Piedmont clay soils, shallow
topsoil:
30 to 40 lbs P2O5
Limit the
amount of
soil-fertilizer
contact on
heavy organic
or clay soils.
Potassium
(K)
Lower leaf tip
and margin
burn, weak
stalks, lodging at
harvest, small
ears, slow
growth
Potassium [plus chloride
(muriate 0-0-60), sulfate,
nitrate, hydroxide, or
magnesium sulfate]
Soil test Sandy or very sandy soils:
50 to 60 lbs K2O
Organic soils (only if K is
deficient): 50 to 60 lbs
K2O
Mineral or clay soils: (only
if K is deficient): 50 to 60
lbs K2O
On deep
sand, apply
just before
planting or
split apply at
planting and
at growth
stage 30.
Calcium (Ca) Terminal and
root tip damage,
dark green,
weakened stems,
ear disorders
Lime, calcium sulfate
(gypsum)
Soil test Apply lime at
recommended rate.
Generally OK
if limed to
target pH.
Magnesium
(Mg)
Interveinal
chlorosis in
older leaves, leaf
curling, margin
yellowing
Dolomitic lime, magnesium
sulfate (epsom salt),
potassium magnesium
sulfate, magnesium oxide
Soil test,
tissue
analysis
If needed: 20-30 lb Mg Generally OK
if dolomitic
lime used.
Sulfur (S) Yellowing of
young leaves,
small spindly
plants, slower
growth and
maturation
Elemental sulfur; sulfate
[plus ammonium, calcium
(gypsum), magnesium
(epsom salt), potassium,
potassium magnesium];
Ammonium thiosulfate;
Sulfur-coated urea
Tissue
analysis or
soil criteria
Sandy soils low in S:
15 to 25 lb S
Deficiency
likely if sandy
surface is 18+
inches deep.
1 This table does not list all available chemical forms of fertilizers or recommend use of any specific form. Percent chemical
analyses included are examples only, and may not reflect the composition of any specific commercial source.
2 Soil samples should be taken to avoid underestimating or overestimating actual needs.
Sulfur Recommendations
Sulfur (S) increases kernel weight, kernel size, grain
protein, yield, and test-weight. Sulfur is required for
the production of chlorophyll and many enzymes
involved in the utilization of N. Consequently, a
small grain crop must have adequate amounts of S
to use N fertilizer property.
Sulfur Deficiency Symptoms
Symptoms of S deficiency include yellowing of
young leaves, small spindly plants, slowed growth,
and delayed maturation. Sulfur deficiency looks very
much like N deficiency except that with S deficiency
the young leaves at the top of the plant are the first
to turn yellow. Sulfur deficiency symptoms usually
occur in patchy spots across the field. Generally, S
deficiencies are only found on deep sandy soils.
However, in recent years, S deficiency symptoms
have occurred in clay and organic soils during cool,
wet weather when the plant is small. Periodic checks
in the late winter and early spring can help identify
fields with S deficiency.
Sulfur Fertilizer Rate
A wheat crop yielding 40 bushels per acre typically
requires 10 pounds of elemental S (4 pounds in the
seed and 6 pounds in the straw). While most of the
agricultural soils in NC will have adequate to high
levels of available S, sandy soils with low levels of
organic matter usually are deficient in S because S is
water soluble and easily leached. On sandy, S
deficient soils, 15 to 25 pounds S per acre can be
applied at planting or with the N sidedress. Sulfur
should be applied before jointing to avoid crop
damage and increase the likelihood of an economic
response.
Calcium and Magnesium
Recommendations
Calcium (Ca) deficiency symptoms include terminal
and root tip damage, dark green stems, weakened
stems, and poor ear formation. Magnesium (Mg)
deficiency symptoms include interveinal chlorosis in
older leaves, leaf curling, and yellowing of the leaf
margins. Generally, Ca and Mg levels are maintained
through dolomitic lime applications. If deficiencies
occur and no pH change is desired, then sulfate
forms such as gypsum (calcium sulfate) or epsom
salts (magnesium sulfate) can be applied at the rates
recommended in Table 9-1.
Micronutrient Management
Due to expense and the potential for toxicity,
applications of micronutrients (including copper,
manganese, and zinc) are generally not made to
small grains unless they are specifically
recommended by a soil test or if specific
deficiencies are identified. Common problems often
found in wheat in NC include manganese
deficiencies on overlimed soils and copper
deficiencies on organic soils.
Copper Recommendations
Proper levels of copper (Cu) in the plant enhance
protein content of the kernel and grain yield.
Copper Deficiency Symptoms
Common Cu deficiency symptoms include stunting,
leaf tip or shoot die-back, and poor upper leaf
pigmentation. Perhaps the best way to diagnose a
Cu deficiency is by observing the leaf tip.
"Pigtailing" or "corkscrewing" of the leaf tip is a
sign of Cu deficiency. Organic soils are naturally
low in Cu, and often deficiency symptoms can be
found in plants grown in these soils, particularly
when the plant and root system are small. Wheat is
very sensitive to Cu deficiency and will be one of
the first crops to show symptoms.
Copper Fertilizer Rate
A wheat crop yielding 40 bushels per acre typically
requires 0.04 pounds of elemental Cu per acre (0.03
pounds in the seed and 0.01 pounds in the straw).
Table 9-2 shows the rate of Cu to use when a soil
test detects a low level or when deficiency
symptoms are noted. Growers should take care to
avoid the over-application of Cu fertilizers since
Nutrient Management 35
high concentrations of Cu can be toxic to the plant.
Timing a Copper Application
The recommended time to apply Cu is preplant.
This avoids the high cost of Cu chelates, eliminates
the chance of leaf burn, and allows a much longer
residual effect. However, if deficiency symptoms
occur, a foliar spray can be applied at much lower
rates than are recommended for soil applications.
Usually, Cu chelates or organic dusts are
recommended for foliar application. Do not apply
Cu after jointing.
Manganese Recommendations
Proper levels of manganese (Mn) in the plant
enhance plant growth and the production of
chlorophyll.
36 Nutrient Management
Table 9-2. Critical micronutrients for small grain production.
Element
Common
deficiency
symptoms
Common fertilizer forms 1
Basis for
fertilizer
rate
Suggested rates per acre
if soil test data are not
available2
Notes
Copper (Cu) Stunting, leaf
tip/shoot
dieback, poor
upper leaf
pigmentation
Copper sulfate, copper oxide,
copper chelates
Soil test,
tissue
analysis
If deficient: apply 0.25 lb
Cu to foliage with 0.50 lb of
hydrated lime, or 2-8 lb3 Cu
to soil.
Boron (B) Leaf thickening,
curling, wilting;
reduced
flowering/
pollination
Boric acid, borax, solubor,
borates
Tissue
analysis
Avoid toxicity,
apply only as
needed.
Iron (Fe) Interveinal
chlorosis of
young leaves
Ferrous sulfate, ferric sulfate,
ferrous ammonium sulfate,
iron chelates
Tissue
analysis
Manganese
(Mn)
Upper leaves
pale green or
streaked
Manganese sulfate,
manganese oxide, manganese
chelate, manganese chloride
Soil test,
tissue
analysis
Coastal plain, sandy soil or
any soil with Mn index less
than 25: 10 lb Mn
If deficient: apply 0.5 lb
Mn to foliage, or 10 lb Mn
to soil.
Overliming
decreases
availability.
Zinc (Zn) Decreased stem
length
(rosetting),
mottling-striping,
interveinal
chlorosis
Zinc sulfate, zinc oxide, zinc
chelates, zinc chloride
Soil test,
tissue
analysis
If deficient: apply 0.5 lb Zn
to foliage, or 6 lb Zn to soil.
1 This table does not list all available chemical forms of fertilizers or recommend use of any specific form. Percent chemical
analyses included are examples only, and may not reflect the composition of any specific commercial source.
2 Soil samples should be taken to avoid underestimating or overestimating actual needs.
3 NCDA guidelines are 2 lb Cu/ac or 6 lb CuSO4/ac for mineral soils, 4 lb Cu/ac or 12 lb CuSO4/ac for mineral-organic soils,
and 8 lb Cu/ac or 24 lb CuSO4/ac for organic soils.
Manganese Deficiency Symptoms
Manganese deficiency symptoms include stunting,
gray specks in the leaf, and pale to almost whitish
upper leaves or streaked yellowing (interveinal
chlorosis) of the upper leaves. Manganese
deficiency can be distinguished from a Mg
deficiency in that Mn affects the upper leaves while
Mg affects the lower leaves. Manganese deficiencies
commonly occur in overlimed soils (pH greater
than 6.5 on mineral soils or greater than 6.1 on
mineral-organic or organic soils) with low cation
exchange capacity. A common situation where Mn
deficiencies are noted is the over-limed areas at the
ends of the field where the spreader truck turned or
where lime was stockpiled.
Manganese Fertilizer Rate
A wheat crop yielding 40 bushels per acre typically
requires 0.25 pounds of elemental Mn (0.09 pounds
in the seed and 0.16 pounds in the straw). Sandy
soils in the NC coastal plain are typically low in
available Mn. Table 9-2 shows the rate of Mn to
use when soil test levels are low or when deficiency
symptoms are noted.
Timing of Manganese Fertilizer Application
The best time to apply Mn on soils with low test
levels is preplant. However, to correct a deficiency if
the soil pH is high, use a foliar application.
Manganese is commonly supplied as manganese
sulfate, manganese oxide, and manganese chelates
or organic complexes. Manganese chelates and
organic complexes are recommended only for foliar
application due to soil reactions that tend to convert
the Mn to unavailable forms. Application of foliar
fertilizers may have to be repeated several times to
correct severe deficiency symptoms on fields that
have been overlimed. Once wheat is jointing,
consider whether response to fertilizer is likely to
outweigh crop damage due to traffic.
Zinc Recommendations
Zinc (Zn) deficiency symptoms include decreased
stem length (rosetting), mottling, and interveinal
chlorosis. Zinc deficiencies are most common if the
soil pH is greater than 6.5 and the soil phosphorus
index is greater than 75. As with other
micronutrients, recommended rates (Table 9-2) are
lower for foliar applications, but residual effects are
greater with soil applications.
Special Consideration for No-Till
Production
Before a field is placed in 100 percent no-till
production, it should be soil tested and brought to
target pH and optimum nutrient levels. Once
adequate fertility levels are achieved throughout the
root zone, no-till production can begin. Long-term
no-till studies suggest that yields and soil fertility
can be maintained even though lime and fertilizer
are applied to the soil surface without
incorporation. Routine soil samples in established
no-till fields should be collected to a depth of 4
inches. Use of starter fertilizers containing N and P
are more important in no-till production because
plant development is delayed.
Special Consideration for Precision
Agriculture
Currently, precision agriculture is being used for
three primary reasons: (1) to identify areas in fields
with different pH or soil test indexes, and vary lime
and fertilizer rates accordingly; (2) to monitor and
map crop yield and moisture content; and (3) to
document material applications, including fertilizers
and pesticides. The cost of collecting grid soil
samples or using a yield monitor must be returned
by decreasing the amounts of lime or fertilizer
applied, increasing crop yield, reducing negative
environmental impacts, or by some combination of
these benefits. Growers are more likely to increase
profits by using precision farming practices in
situations where pH or fertility levels are limiting
wheat yields. An examination of the variability in
soil pH or fertility within a field should indicate the
potential for increasing crop yield through variable-rate
lime or fertilizer applications. If at least a
fourth of the field area has soil nutrient indexes
Nutrient Management 37
below 25, or pH levels below the target value for
that crop and soil class, then it is likely that
precision farming practices will increase wheat
yields and profits.
Special Consideration for Animal Wastes
and Sewage Sludge
Animal waste and sewage sludge can be excellent
sources of nutrients and organic matter for a wheat
crop. Organic forms of P can move deeper in soils
than do inorganic fertilizer sources. Consequently,
they can be advantageous in no-till or conservation
tillage systems. When applying animal waste as a
fertilizer material for wheat, all amendments should
be tested before application to determine optimum
application rates. Soils that are being fertilized with
waste materials should be tested to determine
nutrient levels. The amount of waste material
applied should be based on the need for desirable
nutrients, such as P or K, and the requirement that
levels of P, Zn, Cu, cadmium, lead, and mercury
should not exceed prescribed limits. Producers
should rotate applications as much as possible to
obtain nutrient benefits while minimizing excess
nutrient and toxic metal accumulation. If you use
lime-stabilized sludge or poultry litter, monitor the
soil pH carefully to prevent overliming and possible
Mn deficiency.
Applications of animal waste are most effective
when made prior to planting a small grain crop.
However, topdress applications of poultry or swine
manure can be done in January or early February
with good results. Several good publications on
application of animal waste and/or sludge can be
found online: www.soil.ncsu.edu/publications/
extension.htm .
38 Nutrient Management
10. Insect Pest Management for Small Grains
Dominic Reisig, D. Ames Herbert Jr., Gaylon Ambrose, and Randy Weisz
Insect management can be critical to the economic success of a small grains enterprise, and growers should
be aware of the various insects and management strategies and tactics. These techniques can help you
prevent and detect some potentially serious insect problems before significant loss occurs.
Aphids
Aphids are small sucking insects that colonize small
grains early in the season and may build up in the
spring or fall. They injure the plants by sucking sap
or by transmitting the barley yellow dwarf virus
(BYDV). BYDV is a persistent virus that can be
retained by the aphid for weeks and can be
transmitted in minutes to a few hours of aphid
feeding. Although the exact relationship between
aphid numbers and direct yield loss is unknown,
aphids must be very abundant before injury from
sap-removal occurs. However, low aphid abundance
early in the fall can result in high BYDV occurrence
in winter cereals. Aphid flights in the fall from
grasses surrounding cereals pose the most serious
threat for this disease. Predicting aphid flights is
difficult; flights are generally initiated from cues
such as temperature, sunlight, and increasing
daylength. Flights generally decrease as
precipitation, relative humidity, and wind speed
increase.
Life Cycle
Two species of aphids predominate in small grains:
the English grain aphid (Photo 10-1) and the bird
cherry-oat aphid (Photo 10-2). However, several
others, such as the corn leaf aphid (Photo 10-3) and
the greenbug (Photo 10-4), may be found
occasionally. These aphids are described in Insect and
Related Pests of Field Crops, AG-271 (http://
i p m . n c s u . e d u / AG 2 7 1 / s m a l l _ g r a i n s /
small_grains.html). Aphids' high reproductive rate
enables their populations to quickly build up to
levels that can cause economic loss. However, aphid
populations are usually kept in check by weather
Insect Pest Management 39
Photo 10-1. English grain aphid. Photo by M. Spellman.
Photo 10-2. Bird cherry oat aphid.
Photo 10-3. Corn leaf aphid. Photo by Jack Kelly Clark.
conditions and biological control agents, such as
lady beetles, parasitic wasps, syrphid fly maggots,
and fungal pathogens, which are often abundant in
small grains.
Management
Aphids can occur throughout the growing season.
In early-planted small grains, especially barley, low
levels of aphids in the fall may transmit an infection
of BYDV that can cause symptoms later in the
season. Using a tolerant or resistant variety is an
excellent management tactic. A list of the current
wheat varieties that ar e r esistant to BYDV
( w w w. s m a l l g r a i n s . n c s u . e d u / _Mi s c /
_VarietySelection.pdf) is available on the NC Small
Grain Production Website (www.smallgrains.ncsu.edu).
Insecticides (either as seed treatments or as a foliar
application) to control aphids in the fall are
generally not recommended. There are several
situations, however, in which the use of insecticides
can be beneficial. In areas with a chronic BYDV
history, early-planted small grains may benefit from
preventive neonicotinoid insecticide seed treatments
(such as Gaucho, Cruiser, or NipsIt INSIDE). This
may be important in the NC piedmont, as a recent
study demonstrated that BYDV incidence can
increase when wheat is no-till planted into corn
residue. An alternative to using an insecticidal seed
treatment is to make a foliar application of a long-residual
pyrethroid insecticide at or before three- to
four-leaf stage wheat. BYDV symptoms are easier
to recognize in the spring than the fall. When aphid
populations are relatively low in the fall, an
insecticide application is justified only if BYDV is
anticipated and freezing weather is not expected for
at least one week. As cold weather begins,
populations quickly decline.
Scouting
Scouting for aphids requires searching plants or
examining heads on 10 samples taken at locations
scattered across each field. Each sample should
consist of all plants in 1 foot of row or 10 heads,
depending on plant stage. For foliage examination,
counting aphids on each sample is not feasible;
instead, use a simple estimation technique. Initially,
the scout must "calibrate" by visually establishing a
mental picture of aphids on 1 row foot and then
counting aphids over the entire plant to determine
the actual number. After several repetitions of this
exercise, aphid counting is no longer needed
because a calibrated mental image is available. This
mental image is then used to visually estimate
populations in field scouting. Head-infesting aphids
are similarly estimated, except in this instance the
calibration exercise is done by using heads rather
than whole plants.
Threshold
Aphids may become much more abundant in the
spring than the fall. However, because plants are
actively growing in the spring, they can support
many more aphids without injury. Also, spring-transmitted
BYDV usually does not seriously affect
small grains. Consequently, the thresholds for
applying insecticides are much higher in the spring
compared to those for the fall (see Table 10-1).
Armyworm
Armyworm infests small grains, usually wheat, from
late April to mid-May. They can cause serious
defoliation, injury to the flag leaf, and also cause
head drop. Armyworm populations fluctuate greatly
40 Insect Pest Management
Photo 10-4. Greenbug. Photo by Alton N. Sparks, Jr.,
University of Georgia.
from year to year and across areas of NC. Typically,
the northeastern and mid-coastal counties
experience the most consistent armyworm
problems
Life Cycle
Armyworm moths are one of the first moths to
become active during the spring. Moths prefer to lay
eggs on various grasses, and small grains are very
attractive. Thick planting, narrow row spacing, and
high N rates promote dense and lush growth, which
is conducive to high armyworm infestation.
Young armyworm larvae are pale green, yellowish,
or brown and have a habit of looping as they crawl.
When they become larger (1 to 1½ inches), they are
greenish-brown with pale white and orange stripes
running down their bodies; the head is
honeycombed with faint dark lines (Photo 10-5).
The armyworm is described in Insect and Related Pests
of Field Crops, AG-271 (http://ipm.ncsu.edu/
AG271/small_grains/small_grains.html ).
Armyworm is the only caterpillar found in large
numbers in small grains. They are active at night,
hiding under plant litter (such as old corn stalks)
and at the base of wheat plants during daylight
hours. After dark, they feed on foliage from the
bottom of the plant upward. As they eat the lower
foliage or as it is destroyed by leaf pathogens, the
armyworm larvae feed higher, eventually reaching
the flag leaf. If populations are high, large
caterpillars may also feed on the stem just below the
head.
Management
Management of armyworm is based on scouting,
thresholds, and resulting application of insecticides
when necessary. Infestations of armyworms are not
easily detected by casual observation because
caterpillars hide during the day. Fortunately, several
signs of armyworm infestation occur, and
caterpillars can also be monitored if the correct
technique is used. Blackbirds (grackles and red-winged
blackbirds) commonly search for
armyworms in small grains. Any field with
significant bird activity should be scouted. Signs of
armyworm leaf feeding and caterpillar droppings
can also be good indicators. Feeding is sometimes
inconspicuous because small caterpillars do not eat
much and feeding signs are often concentrated on
the lower part of the plant. When caterpillar
Insect Pest Management 41
Photo 10-5. Armyworm. Photo by M. Spellman.
Table 10-1. Aphid thresholds for small g grains in the fall and spring.
Fall
Spring
Plant Height (inches)
After heading
3 - 6 4 - 8 9 - 16
20 aphids per row foot, and
BYDV has been a chronic
problem or is expected, and
cold weather is not forecast for
at least one week.
aphids per row foot 25 aphids per head and 90% of
heads infested, or
50 aphids per head and only 50%
of the heads infested
100 200 300
populations are high, droppings may be seen easily
but should not be confused with weed seed.
Scouting
Fields should be scouted for armyworms in May
when caterpillars are normally small. Thorough
scouting should not be done until the caterpillars
are at least 3/8-inch long because populations of
small worms are difficult to estimate accurately and
often die out. Once caterpillars reach 3/8-inch or
more in length, take at least 5 samples per field (10
samples in larger fields of 20 acres and more) by
examining all the wheat in 3 feet of one row. Look
for and count the caterpillars in litter around the
base of plants and under old crop residue. Pay
special attention to fields in which birds are active.
Fields should be scouted weekly until a treatment or
no-treatment decision is made. Re-infestation of
caterpillars in May after a successful insecticide
application does not occur.
Threshold
The economic threshold is 6 half-inch or longer
caterpillars per square foot. The threshold changes
to 12 caterpillars per square foot when grain is near
maturity.
Cereal Leaf Beetle
Cereal leaf beetle, a native to Europe and Asia, was
first detected in Michigan in 1962. Since then, it has
spread throughout most of the Midwestern and
Eastern United States and has become a significant
pest of VA and NC small grains. This insect can
become very numerous in small grain fields, and the
larvae may reduce grain yield by eating the green
leaf tissue. Preferred small grain hosts for the larvae
are wheat, oats, and barley, although the adults will
feed on corn, wild grasses and all other cereals.
Life Cycle
Adult beetles (Photo 10-6) are about 3/16-inch long
and have metallic looking, bluish-black heads and
wing covers. The legs and front segment of the
thorax are rust-red. Adults overwinter in grasses,
ground litter, or other debris, within wooded areas,
or in other protected sites in the vicinity of last
season’s grain fields. In the spring, they emerge
when the temperature is 48 to 50°F to feed, mate,
and lay eggs in small grain fields.
Eggs (Photo 10-7) are elliptical, about 1/32 of an
inch long, and yellow when newly laid, but later
become darker to orange-brown and finally black
before hatching. Most often the eggs are laid singly
or end-to-end in short chains on the upper leaf
surface between, and aligned with, the leaf veins.
Egg laying occurs during March and into April with
more larvae found in poorly tillered small grain
fields. Females lay 100 to 400 eggs each. These eggs
will hatch in about 5 days.
Larvae (Photo 10-8) are slug-like and have yellowish
bodies with heads and legs that are brownish-black.
However, body coloration is usually obscured by a
black globule of mucus and fecal matter held on the
body, giving the larvae a shiny black, wet
42 Insect Pest Management
Photo 10-6. Cereal leaf beetle adult.
Photo 10-7. Cereal leaf beetle eggs.
appearance. Larvae develop in 10 to 12 days. Peak
larval populations occur in mid-April to early May.
Upon reaching full size, they dig ½ to 2 inches into
the ground and pupate. Pupation usually lasts 15 to
20 days.
Injury to Small Grains
Although adults will feed on young small grain
plants, their feeding does not affect the plant's
performance. However, larvae eat long strips of
green tissue from between leaf veins and may
skeletonize entire leaves (Photo 10-9), leaving only
the transparent lower leaf tissue. Severely defoliated
fields can take on a white "frosted" cast (Photo
10-10) as green tissue is lost on the upper leaves.
Yield Reduction
Leaf feeding indirectly reduces the plant's ability to
make its food and limits reproductive growth,
particularly if the upper leaves are destroyed. Larger
larvae are by far the most damaging. Yield
reductions of 10 to 20 percent are typical in
infested commercial fields. Yield reductions of 45
percent have been observed when defoliation was
near 100 percent and the damage occurred early in
the heading period. Damage late in the head-fill
period does not have a great impact.
Scouting Method
• Take samples at a minimum of 10 random sites
in the interior of the field (avoid the edges). At
each site, examine 10 stems for eggs and larvae.
This will result in 100 stems per field being
examined.
• Eggs may be on the leaves near the ground.
Record the number of eggs and larvae counted at
each sample site and then calculate the total
number of eggs and larvae found in the field.
• If there are more eggs than larvae, scout again in
five to seven days. This is important because egg
mortality can be very high. A large number of
eggs does not necessarily mean there will be a
high larvae population.
Insect Pest Management 43
Photo 10-8. Cereal leaf beetle larva.
Photo 10-9. Wheat leaf damage caused by cereal leaf
beetle larvae feeding.
Photo 10-10. A wheat field severely damaged by cereal
leaf beetle feeding.
• If there are more larvae than eggs, there is no
need to scout again. A decision about applying an
insecticide for control can now be made.
Threshold
When the scouting results show that there are more
larvae than eggs, peak egg laying has passed and it is
the correct time to use the spray threshold. If there
are 25 or more eggs plus larvae on 100 stems, the
threshold has been met.
Management Tips
Cereal leaf beetle adults are attracted to dense
highly-tillered wheat fields, but more larvae per tiller
are found in poorly-tillered fields. Management
practices that lead to densely tillered stands by mid-
February can help to reduce the risk of having a
cereal leaf beetle infestation. These practices
include planting on-time, using high quality seed
planted at recommended seeding rates, making sure
that preplant fertility is adequate for rapid fall
growth, and applying a split nitrogen application in
February and March if additional tillering is needed
in the spring.
Cereal leaf beetle is easily controlled with low rates
of many insecticides if they are applied when the
threshold is met. Because only one generation
hatches per year, if insecticides are applied based on
the use of thresholds, one application will give
adequate management. However, if insecticides are
applied early before threshold levels are met (such
as with top-dress nitrogen), reduced application
rates may not be adequate. And even when full label
rates are used, a second application may be required
later in the season.
Insecticides labeled for cereal leaf beetle control in
small grains are listed in Table 10-2. To be most
effective, insecticides must be applied by early head-fill,
before the larvae cause significant yield-reducing
defoliation. In making a choice about insecticides,
consider the presence of aphids or armyworms.
Both carbamates and pyrethroids kill aphid parasites
and predators. Carbamates can sometimes allow a
serious aphid increase. Therefore, a carbamate
should not be applied against cereal leaf beetle if
aphids are a potential threat. Carbaryl, beta-cyfluthrin,
lambda-cyhalothrin, and zeta-cypermethrin
provide excellent management, with
good residual effects at least 14 days after treatment.
Spinosad provides adequate management under
normal situations, with minimal residual effects.
Under heavy pressure situations, using spinosad is
equivalent to doing nothing.
44 Insect Pest Management
Table 10-2. Insecticides labeled for cereal leaf beetle management (2013). Although they may be as effective as
the chemicals listed here, generic formulations are not listed nor are pre-mixed products with multiple
insecticide classes.
Insecticide Class Active Ingredient Trade Name Formulation/A
Carbamates methomyl Lannate LV 1 to 2 pt
Lannate SP 0.25 to 0.5 lb
carbaryl Sevin brand XLR PLUS 1 pt
Pyrethroids beta-cyfluthrin Baythroid XL 1.0 to 1.8 fl oz
lambda-cyhalothrin Karate Z or Warrior II 1.92 fl oz
Karate or Warrior 2.6 fl oz
zeta-cypermethrin Mustang Max EC 1.6 to 4.0 fl oz
Hessian Fly
Why Has Hessian Fly Become a Problem?
In recent years, numerous NC fields have suffered
extensive losses because of Hessian fly infestations.
Historically a wheat pest in the Midwest, changes in
field-crop production including early planted wheat,
increased adoption of no-tillage double-cropped
soybeans, and the use of wheat as a cover crop for
strip-tillage cotton and peanut production have
permitted the Hessian fly to reach major pest status
in NC.
Hessian Fly Life Cycle
The adult Hessian fly is a small, long-legged, two-winged
insect that resembles a small mosquito
(Photo 10-11). It is one of many species of gnat-sized
flies that may be found in wheat fields. The
female Hessian fly adult is reddish-brown and black
in color and about 1/8-inch long. The slightly
smaller males are brown or black. The elliptical eggs
are very small and orange. Eggs are deposited singly
or end-to-end in “egg lines” between the veins on
the upper surface of the young leaves (Photo
10-12). Newly hatched larvae (maggots) are also
orange for 4 or 5 days before turning white (Photo
10-13). As larvae mature, a translucent green stripe
appears down the middle of the back. The maggot
is about ¼ inch long when full grown. The maggot
transforms into an adult fly inside a dark-brown
case, or puparium, that resembles a flaxseed in size
and shape. Newly formed puparia will be a lighter-brown
color that transforms to a mahogany-brown
color with age. Puparia or "flaxseeds” (Photo 10-14)
are located under leaf-sheaths and usually below
ground on young tillers or below the joint in older
plants.
Hessian fly can be found in small numbers in most
wheat fields at harvest. If the wheat stubble is
destroyed after harvest, the fly dies and the life cycle
is broken (Figure 10-1). If, however, the wheat
stubble is left in the field, the fly can survive as
“flaxseeds” in the stubble through the summer. In
late August and September, adults emerge from the
“flaxseeds” and lay eggs on volunteer wheat or on
early planted cover-crop wheat. A first generation
can be completed on these plants, and the next
generation adults emerging from cover-crop or
volunteer wheat plants can lay eggs on wheat
planted for grain in October and November, before
Insect Pest Management 45
Photo 10-11. An adult Hessian fly.
Photo 10-12. Hessian fly eggs.
Photo 10-13. Large Hessian fly larvae.
the weather turns cold enough to kill the adult flies.
Often Hessian flies begin depositing eggs very soon
after seedling emergence.
Once Hessian flies are established on a new wheat
crop, their eggs hatch within a few days and the tiny
maggots migrate into the whorl of small wheat
plants, ultimately locating below ground at the
stem’s base, where they enter the pupal stage. While
feeding, the larvae injure the plants by rupturing
leaf or stem cells. They cause the plant to form an
area of nutritive tissue around the base to enhance
their feeding, which can result in tiller stunting and
dieback. A heavy infestation on early-stage plants
may greatly reduce plant stand. A new generation of
adults usually emerges in March depending on the
weather, lays eggs, and produces new larvae that
migrate to the stem joints where they feed and
cause further injury. This spring injury may kill the
wheat, but usually only results in weakened stems,
small heads, and poorly filled grain heads with low-quality
kernels. Often, wheat lodges in seriously
infested fields.
46 Insect Pest Management
Photo 10-14. Hessian fly puparia or “flaxseed”.
<
No-till beans allows
pupa to over-summer
3rd generation adults
re-infect wheat plants
Pupae overwinter in tillers
Maggots kill fall tillers
Maggot feeding
causes lodging
Summer
Autumn
Winter
Spring
Disking before beans kills
pupae & ends the life cycle
Pupae in wheat
straw at harvest
Eggs laid on volunteer
wheat, grassy weeds or early
planted cover-crop wheat
1st generation adults emerge in
soybean fields & seek new host
2nd generation adults emerge &
seek wheat planted for grain
Figure 10-1. The Hessian fly life cycle.
Management
Rotation
Because the Hessian fly life cycle depends largely on
the presence of wheat stubble, rotations that
prevent new wheat from being planted into or near
a previous wheat crop’s stubble will be an effective
way to prevent infestations. Avoid planting wheat
into last season’s wheat stubble! Continuous no-tillage
wheat, double-cropped with soybeans, may
result in severe problems and should be avoided in
Hessian fly problem areas. Additionally, since the
Hessian fly is a weak flier, putting distance between
the location of new wheat plantings and the
previous season’s wheat fields can be a successful
method of preventing new infestations. Although
Hessian fly can become serious under other
situations, most serious infestations occur when
wheat is planted early into wheat stubble or into
fields next to wheat stubble.
Tillage: Disking wheat stubble after harvest
effectively kills the Hessian fly. Planting soybean no-till
into wheat stubble enhances Hessian fly survival
by preserving the site where puparia spend the
summer. Burning wheat straw will reduce puparia,
but many puparia are found below the soil surface.
Therefore, burning is not as effective as disking and
is not recommended as a management method.
Choosing Cover Crops
Serious Hessian fly infestations have occurred
where wheat for grain was planted near early-planted
wheat for cover or where early-planted
wheat was present for dove hunting. In cropping
systems where cover crops are used, such as in
strip-till cotton or peanut production, the use of
other small grains besides wheat will reduce Hessian
fly populations. Although Hessian fly can develop
on grasses in more than 17 genera, some are more
favorable hosts for egg laying and development.
Oats, rye, and triticale are not favorable for Hessian
fly reproduction and do not serve as a nursery,
making these grains preferable over wheat for cover
cropping in areas where wheat for grain is also
produced. If triticale is used for cover cropping,
varieties that are adapted to NC should be planted.
Delayed Planting
Because freezing temperatures kill Hessian fly
adults, a traditional method for preventing Hessian
fly infestation is to delay planting until after the first
freeze (often called the fly-free date). This concept
has not worked well in NC because an early freeze
is not a dependable event. Often a “killing freeze”
does not occur until December in many areas of
NC, after most growers need to have wheat planted
for agronomic purposes. There is no reliable fly-free
date in North Carolina.
Resistant and Tolerant Varieties
Correct varietal selection is probably the most
inexpensive and effective method of Hessian fly
management (Photo 10-15). Many wheat varieties
are advertised as having Hessian fly resistance.
Unfortunately, in most cases, resistance is based on
a single gene present in the variety that must match
a gene in the Hessian fly. This resistance often
works by causing cell death and fortification of the
cell wall around the nutritive tissue where the
Hessian fly feeds. To be effective in NC, wheat
varieties must be specifically resistant to the local
Hessian fly genotype. A list of the current wheat
var i e t i e s that ar e r e s i s tant t o He s s ian f l y
( w w w. s m a l l g r a i n s . n c s u . e d u / _Mi s c /
Insect Pest Management 47
Online VIDEO:
Identifying & Managing Hessian Fly
www.smallgrains.ncsu.edu/hessian-fly.html
_VarietySelection.pdf) is available on the NC Small
Grain Production Website (www.smallgrains.ncsu.edu).
In most cases, varieties rated as having “good”
resistance should provide enough protection to
avoid economic losses due to Hessian fly. In areas
with severe Hessian fly problems, however, the use
of resistant and tolerant varieties may not be
sufficient to prevent infestations from occurring.
Systemic Se