Corn Traits: What Pays in Virginia

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Corn Traits What Pays in Virginia

• Wade Thomason

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Pests

• Weeds
• Barnyardgrass, bermudagrass, broadleaf
  signalgrass, crabgrass, fall panicum, foxtails,
  goosegrass, johnsongrass, quackgrass, sandbur,
  shattercane, texas panicum, nutsedge, Eastern
  black nightshade, burcucumber, cocklebur,
  jimsonweed, lambsquarters, morningglory, pigweed,
  ragweed, sicklepod, smartweed, spurred anoda,
  prickly sida, tropic croton, velvetleaf

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Pests

• Weed Control Programs
• Tillage?
• Cover Crop?
• Pre vs. Post?
• Crop Rotation?
• Weeds Present?
• Selective herbicides vs. non-selective?
• Simplicity?
• Cost?

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Herbicide Tolerance

• Glyphosate tolerance
• Glufosinate tolerance
• Imidazolinone tolerance

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Herbicide Tolerance

• Imidazolinone tolerant - IMI (IR or IT) or
  Clearfield (Cl)
• Developed by tolerance selection to be
  resistant/tolerant to imidazolinone herbicides
  (pursuit, scepter).
• Originally introduced to deal with herbicide
  carryover.
• Products like Lightning can be directly applied -
  controls a broad spectrum of weeds and volunteer
  RR corn
• Some IMI varieties (IR) also are tolerant to some
  sulfonylurea (e.g., Accent, Exceed) and
  sulfonamide (Broadstrike products, Python)
  herbicides and are used to reduce the injury
  potential of these products when applied alone or
  in combination with organophosphate (OP)
  insecticides.

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Herbicide Tolerance

• Glyphosate Tolerance/Roundup Ready - RR
• Developed using genetic engineering techniques.
• Allows postemergence applications of Roundup and
  some other glyphosate products directly to corn.
• This system provides broad-spectrum annual and
  perennial weed control in corn.

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Herbicide Tolerance

• LibertyLink Glufosinate resistant (Gu) corn
• Genetically engineered to allow over-the-top
  applications of Ignite (glufosinate) herbicide.
• This program should provide broad-spectrum
  control of annual broadleafs and grasses of low
  to moderate pressure.
• Sequential applications or tank mixtures may be
  required for new weed flushes and perennials.

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• Approximately 1200 growers in six states
  (approximately 200 per state in Iowa, Illinois,
  Indiana, Mississippi, North Carolina, and
  Nebraska)

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Herbicide Tolerance Traits
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2009 State Grain, Shenandoah
3 bu/ac advantage?
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Avg 2007-2009 Isolines Study, Blacksburg
1.1 ton/ac advantage?
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CostBenefit
Kernels per bag 80000
Planted population, seeds/acre 28000
Grain yield (bu/A) to pay for seed at various seed and corn prices Grain yield (bu/A) to pay for seed at various seed and corn prices Grain yield (bu/A) to pay for seed at various seed and corn prices Grain yield (bu/A) to pay for seed at various seed and corn prices Grain yield (bu/A) to pay for seed at various seed and corn prices
Base Hybrid Base Hybrid RR RR
Seed Cost per Bag Seed Cost per Bag Seed Cost per bag Seed Cost per bag
160.00 160.00 220.00 220.00
Corn price Seed Cost per Acre Seed Cost per Acre Seed Cost per Acre Seed Cost per Acre Bushels to pay
/bu 56.00 56.00 77.00 77.00 for added seed cost
2.50 22.4 22.4 30.8 30.8 8.4
3.00 18.7 18.7 25.7 25.7 7.0
3.50 16.0 16.0 22.0 22.0 6.0
4.00 14.0 14.0 19.3 19.3 5.3
4.50 12.4 12.4 17.1 17.1 4.7
5.00 11.2 11.2 15.4 15.4 4.2

Grain yield (bu/A) to pay for seed at various seed cost and pesticide savings Grain yield (bu/A) to pay for seed at various seed cost and pesticide savings Grain yield (bu/A) to pay for seed at various seed cost and pesticide savings Grain yield (bu/A) to pay for seed at various seed cost and pesticide savings Grain yield (bu/A) to pay for seed at various seed cost and pesticide savings

Pesticide Seed Cost per Acre Seed Cost per Acre Seed Cost per Acre Seed Cost per Acre
cost savings 56.00 56.00 77.00 77.00
0.00 14.0 14.0 19.3 19.3
10.00 14.0 14.0 16.8 16.8
20.00 14.0 14.0 14.3 14.3
30.00 14.0 14.0 11.8 11.8
40.00 14.0 14.0 9.3 9.3
4/bu
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Where to put these products and how to manage
them

• Herbicide tolerance
• Target hard-to-control weeds.
• Evaluate real costs
• Consider weed management in other crops
• Resistance management

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Chronic Pest Problems
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European Corn Borer
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European Corn Borer

• An average of one European corn borer cavity per
  stalk across an entire field can reduce yield by
  as much as 5 by the first generation and 2.5 by
  the second generation.
• BUTprediction insect populations prior to the
  season is not reliable.
• BUTtreating for the pest in-season is difficult
  at best.

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European Corn Borer

• Thresholds
• First Generation ECB
• 80 percent or more of the plants exhibit whorl
  feeding damage and if 80 percent or more of the
  damaged plants (i.e., 8 out of the 10 dissected
  plants) have at least 1 live larva per plant. (V4
  or 10-12 inch plants)
• Second Generation ECB
• 35 percent or more of the plants in the pre- to
  post-tasseling stage of development have at least
  1 egg mass per plant. (24 inch plants tassel)

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European Corn Borer

• Statewide economic infestations have occurred in
  only 3 out of the last 22 years.
• Many corn hybrids are able to tolerate moderate
  levels of leaf and stalk injury without economic
  yield loss.
• Also, corn grown for silage rarely needs to be
  treated for ECB.

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European Corn Borer

• How often is any particular field likely to have
  an average of one or more cavities per stalk at
  the end of the season?

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ECB

• What is the benefit?
• Of 172 cornfields surveyed from 1997-99, only 2
  exceeded the economic threshold for ECB damage (1
  or more, gt 0.5-inch tunnels per stalk)
  (Youngman).
• 2004 Eastern VA on-farm plots
• 17 trials reported
• 6 had obvious ECB damage
• 10 infested ? 14 bu/A
• 25 infested ? 30 bu/A
• 90 infested ? 54 bu/A

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CB Bt Effects 2005
Corn borer tunnels/plant 2.0
2.1 4.0 2.7
Average of three hybrids Significantly different
Average benefit 2.7 Tons/A 4.2 /tunnel yield
response
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CB Bt Effects 2006
Corn borer tunnels/plant 1.1
0.8 0.8
0.9
Average of three hybrids Significantly different
Average benefit 1.4 Tons/A 6.2 /tunnel yield
response
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ECB

• Most corn ( 90) planted timely in Virginia will
  likely not realize an economic benefit from Bt
  corn because of the lack of European corn borer
  pressure early in the season.
• But gain protection from corn ear worm, fall
  armyworm, black cut worm (Cry1f only), and indian
  meal moth in shelled corn.
• It is strongly recommended that Bt corn be
  planted anywhere late-planted corn (i.e., corn
  planted mid to late May or later) is grown in
  Virginia because of the increasing risk of corn
  borer damage.

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ECB
Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices
Base Hybrid CB
Seed Cost per Bag Seed Cost per bag
160.00 200.00
Silage price Seed Cost per Acre Seed Cost per Acre Tons to pay
/ton 56.00 70.00 for added seed cost
15.00 3.7 4.7 0.9
20.00 2.8 3.5 0.7
25.00 2.2 2.8 0.6
30.00 1.9 2.3 0.5
35.00 1.6 2.0 0.4
40.00 1.4 1.8 0.4
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Where to put these products and how to manage
them

• European Corn Borer
• A history of significant ECB damage in a field
• Very early-planted long-season hybrids will be
  attractive to both first- and second-generation
  ECB.
• Very late plantings will also be attractive to
  ECB
• Fields planted in low areas along streams and
  rivers are more like to experience economic
  infestations of ECB.
• Fields managed for high yield or at higher
  population levels will benefit more from the
  technology than those with a low yield potential
  (for example, 3 of 150- bushel-per-acre corn is
  greater than the same percentage of 100-
  bushel-per-acre corn).

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Corn Root Worm
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Corn on Corn No-till
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Corn on Corn after Rye
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Late Planted Corn on Corn
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Corn on Corn and Drought
In Summary

• Opportunities exist in our region for transgenic
  hybrids for silage production
• Later planted (CB)
• Corn on Corn (RW)
• Weed issues
• Stress

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2005 RW Bt Silage Effects
Corn Rootworm (0-3) rating 0.16
0.12 0.97 0.42

Average of three hybrids Significantly
different from RW Bt
RW/Force advantage 1.4 Tons/A CB RW effect
3.1 tons/A
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2006 RW Bt Silage Effects
Corn Rootworm (0-3) rating 0.28 0.09
1.03 0.47
Average of three hybrids Significantly
different from RW Bt
RW/Force advantage 0 Tons/A CBRW effect 1.7
Tons/A
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RW Bt Silage Effects
2006
Average of three hybrids
Forage quality effects NS
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Effects of Traits on Mycotoxins
2006
Aflatoxin Vomitoxin Zearalone T2 Fumonisin
Delaware ppb ppm ppm ppm ppm
RR2 1.1 0.0 0.1 0.004 0.156
RR2/YGP 2.2 0.1 0.1 0.006 0.098
Sig. NS NS NS NS
Pennsylvania          
RR2 4.4 1.1 0.3 0.012 0.024
RR2/YGP 3.8 0.5 0.2 0.010 0.000
Sig. NS NS NS NS
Maryland          
RR2 3.6 0.117 0.087 0.021 0.105
RR2/YGP 3.0 0.210 0.084 0.019 0.018
Sig. NS NS NS NS NS
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Preliminary Conclusions

• CB BT had significant effect on yield in medium
  high pressure environments
• Average yield response 5.2/tunnel or 2.0 tons/A
• No effect on forage quality
• RW BT had significantly higher yields than Force
  in one of two years
• Average difference between RW and Force was 0.7
  tons/A
• No effect on forage quality
• CB RW BT had significant effect on yield in at
  least one of two years
• Average yield response compared to check was 2.4
  tons/A
• No consistent effect on mycotoxins

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Corn Root Worm

• Economics

Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices
Base Hybrid Base Hybrid Triple Stack Triple Stack
Seed Cost per Bag Seed Cost per Bag Seed Cost per bag Seed Cost per bag
160.00 160.00 236.00 236.00
Silage price Seed Cost per Acre Seed Cost per Acre Seed Cost per Acre Seed Cost per Acre Tons to pay
/ton 56.00 56.00 82.60 82.60 for added seed cost
15.00 3.7 3.7 5.5 5.5 1.8
20.00 2.8 2.8 4.1 4.1 1.3
25.00 2.2 2.2 3.3 3.3 1.1
30.00 1.9 1.9 2.8 2.8 0.9
35.00 1.6 1.6 2.4 2.4 0.8
40.00 1.4 1.4 2.1 2.1 0.7

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Corn Root Worm

• Economics

Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices Silage yield (ton/A) to pay for seed at various seed and corn prices
Base Hybrid VT3
Seed Cost per Bag Seed Cost per bag
160.00 266.00
Silage price Seed Cost per Acre Seed Cost per Acre Tons to pay
/ton 56.00 93.10 for added seed cost
15.00 3.7 6.2 2.5
20.00 2.8 4.7 1.9
25.00 2.2 3.7 1.5
30.00 1.9 3.1 1.2
35.00 1.6 2.7 1.1
40.00 1.4 2.3 0.9
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Where to put these products and how to manage
them

• Corn Root Worm
• A history of significant CRW damage in a field
  usually is a good indicator that the conditions
  in the field are conducive to the pest.
• Flourish with continuous corn or with pumpkins in
  the rotation.
• Scouting is highly predictive.

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Corn Root Worm

• Western corn rootworm beetles should be sampled
  in July and August to determine whether a control
  measure is needed the following year.
• Sticky traps
• Scouting for adults
• When scouting fields that have been in corn more
  than one year, an average count of 1.0 beetle or
  more per ear zone indicates that a granular
  insecticide should be applied if the field is to
  be planted in corn the following year. When
  scouting first year corn, control for rootworms
  the following year if the average count is 0.75
  beetles or more per ear zone, because primarily
  egg-laying females migrate to new cornfields.

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Corn Traits What Pays in Virginia

• It depends
• CB protection alone adds 0.4 to 2.0 ton/ac silage
  (ave 0.8 ton/ac)
• CBCRW (when CRW is present) adds 2.0 to 3.0
  tons/ac
• Will the added yield pay for the added cost?