Managing Weeds in Sweet Corn

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Managing Weeds in Sweet Corn

• Joel Felix Douglas Doohan
• OSU/ OARDC, Wooster

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Weeds Plants adapted to disturbance
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Herbicides Create More Disturbance

• Potency and persistence, increases the likelihood
  of resistance

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Optimizing Weed Control

• Not depending entirely upon herbicides
• Why not?
• Lose effectiveness
• Using herbicides effectively
• varietal sensitivity

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Optimizing Weed Control

• Use a variety of methods (Integration)
• Cultural Methods
• Chemical Methods
• Mechanical Methods

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Cultural Methods

• Prevention eradication

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Cultural Methods

• Crop Rotation
• winter cereals
• forages
• Roundup Ready
• cultivated vegetables
• non-triazine herbicides

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Cultural Methods

• Mechanical
• ca 50 if Ohio growers cultivate sweet corn

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Herbicides Options

• PREPLANT
• PRE
• POST (new labels)
• Permit
• Prowl
• Aim

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PROWL - Sweet Corn

• Use on sweet corn previously restricted to a few
  states.
• Controls triazine-resistant common lambsquarters.
• Long-standing concerns about sweet corn
  sensitivity to PROWL, especially when seeded
  shallow and on sandy soils.

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Prowl sweet corn

• Planting depth is important
• at least 1.5
• Crop stage of growth is important
• spike or later
• Both must be right

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Permit(halosulfuron)

• 1 or 2 applications of 1 1/3 oz/A.
• 2/3 oz/A reduced tuber density by 80. (Nelson
  Renner)

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Permit varieties tested

• Seneca Dancer
• Temptation
• Sweet Rhythm
• Amazingly Sweet
• Kandy King
• Immaculata
• Fortune
• Confection

• Bandit
• Seneca Daybreak
• Sensor
• Ice Queen
• X-Tra Tender
• Kandy Korner
• Silver King

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Permit Results 2000/ 2001
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Permit Yield 2000/ 2001
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POST

• AIM
• weed control
• controls velvetleaf, nightshade, pigweed, annual
  morningglories and lambsquarters
• apply when weeds are 1-4 inches tall

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Aim
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POST

• AIM
• slight injury common
• apply up to 8 collar stage on corn
• position nozzles 18 inches above crop
• do not apply within 6-8 hours of rain
• do not spray into the whorl
• GROWER ASSUMES LIABILITY

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Herbicides Options

• PREPLANT
• PRE
• POST (experimental)
• Permit
• Prowl
• Aim
• Distinct
• Callisto
• Option 360

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POST

• Distinct
• weed control
• Canada thistle, bindweed, triazine and ALS
  resistant weeds

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Distinct
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POST

• Callisto
• also used PRE
• weed control
• Most annual broadleaf weeds
• Weak on morningglories, mallow, knotweeds

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Callisto
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POST

• Option 360
• weed control
• Excellent residual control of annual grasses
• Controls a wide range of broadleaf weeds
• Except ALS resistant biotypes

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Option 360AE F 130360 WG62/WG61
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What we learned

• Use multiple methods of control
• Cultural, mechanical, chemical
• Prowl
• Permit (varietal sensitivity)
• Aim
• Potential new herbicides