Pacific Northwest Insect Management Handbook

Field and silage corn-Corn earworm

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Image related to Field and silage corn-Corn earworm
Corn earworm
Helicoverpa zea Boddie
Adult
© Ken Gray Insect Image Collection
Image related to Field and silage corn-Corn earworm
Corn earworm
Helicoverpa zea Boddie
Immature showing damage
© Ken Gray Insect Image Collection
Image related to Field and silage corn-Corn earworm
Corn earworm
Helicoverpa zea Boddie
Immature showing damage
© Ken Gray Insect Image Collection

Helicoverpa zea

Pest description and crop damage Large green, brown, or yellow worms that feed within silk and ears. First-generation larvae may feed as "bud worms," damaging leaf whorls and newly forming ears.

Management-chemical control

  • alpha-cypermethrin (Fastac CS) at 0.011 to 0.025 lb ai/a. REI 12 hr. PHI 30 days grain and stover; 60 days forage. Retreatment interval 3 days. Do not exceed 0.075 lb ai/a per season.
  • beta cyfluthrin (Baythroid XL) at 0.013 to 0.022 lb ai/a. PHI 0 days for green forage and 21 days for grain or fodder. REI 12 hr. Do not exceed four applications or 0.088 lb ai/a per season.
  • bifenthrin (Brigade 2EC, Sniper) at 0.033 to 0.1 lb ai/a. PHI 30 days for harvest, grazing, or cutting for feed. REI 12 hr. Do not apply more than 0.3 lb ai/a per season.
  • bifenthrin/zeta-cypermethrin (Hero EW) at 0.04 to 0.1 lb ai/a. PHI 30 days grain and stover; 60 days forage. REI 12 hr. Do not graze for 30 days after treatment. Do not exceed 0.4 lb ai/a per season.
  • Burkholderia spp. (Venerate XC) at 1 to 4 qt/a. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • carbaryl (Sevin 4F) at 1 to 2 lb ai/a. PHI 14 days for forage or silage grazing, and 48 days for grain harvest. REI 24 hr. Do not exceed four applications or 8 lb ai/a per season. Latex-based formulations, such as Sevin XLR Plus, are less hazardous to bees.
  • chlorantraniliprole/lambda-cyhalothrin (Besiege) at 0.045 to 0.08 lb ai/a. PHI 21 days. REI 24 hr. Do not exceed 0.12 lb ai of lambda-cyhalothrin or 0.2 lb ai of chlorantraniliprole per acre per growing season. Retreatment interval 7 days.
  • chlorantraniliprole (Coragen) at 0.045 to 0.098 lb ai/a. PHI 14 days. REI 4 hr. Do not exceed 4 treatments nor 0.2 lb ai/a per season. Retreatment interval 7 days.
  • chlorpyrifos (Lorsban Advanced) at 0.7 to 0.94 lb ai/a. PHI 21 days before harvest of grain or ears. REI 24 hr. Apply as a broadcast spray. Do not exceed 3 lb ai/a per season for all chlorpyrifos treatments. RESTRICTED USE IN OREGON.
  • Chromobacterium subtsugae (Grandevo) at 0.6 to 0.9 lb ai/a per 100 gal. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • cyfluthrin (Tombstone) at 0.025 to 0.044 lb ai/a. PHI 0 days for green forage and 21 days for grain or fodder. REI 12 hr. Retreatment interval 7 days. Do not exceed four applications or 0.175 lb ai/a per season.
  • deltamethrin (Delta Gold) at 0.018 to 0.022 lb ai/a. PHI 21 days for grain or fodder, or 12 days for forage or grazing. REI 12 hr. Do not apply more than 0.095 lb ai/a per season. Retreatment interval 21 days. Limit 5 treatments per year.
  • esfenvalerate (Asana XL) at 0.03 to 0.05 lb ai/a. PHI 21 days. REI 12 hr. Do not exceed 0.25 lb ai/a per season.
  • gamma cyhalothrin (Declare) at 0.0075 to 0.0125 lb ai/a. Effective prior to larvae entering the ear only. PHI 1 day for grazing and forage, or 21 days for fodder and silage. REI 24 hr. Do not exceed 0.06 lb ai/a per season.
  • HZNPV (Gemstar LC)-Insecticidal virus product. OMRI-listed for organic use.
  • indoxacarb (Steward EC) at 0.059 to 0.11 lb ai/a. PHI 14 days grain, 1 day forage, fodder, silage. REI 12 hr. Limit 2 treatments. Do not exceed 0.22 lb ai/a per year.
  • lambda-cyhalothrin (Warrior II) at 0.015 to 0.025 lb ai/a. PHI 21 days. REI 24 hr. Do not apply more than 0.12 lb ai/a per season, 0.06 lb ai/a after silk initiation, or 0.03 lb ai/a after milk stage.
  • methomyl (Lannate SP) at 0.22 to 0.45 lb ai/a. PHI 21 days for ears, 3 days for forage, 21 days for fodder. Do not exceed 2.25 lb ai/a or 5 treatments per season. REI 48 hr. Retreatment interval 5 to 7 days.
  • methoxyfenozide/spinetoram (Intrepid Edge) at 0.188 to 0.281 lb ai/a. PHI 28 days. REI 4 hr. Do not exceed 0.625 lb ai methoxyfenozide and 0.125 lb ai spinetoram per acre per year. Limit 3 treatments. Retreatment interval 4 days except 2 days for silking.
  • permethrin (Ambush 25W) at 0.1 to 0.2 lb ai/a. PHI 0 days for forage; 30 days for grain harvest or fodder. REI 12 hr. Allow 6 days between treatments. Do not apply more than 0.6 lb ai/a per season.
  • spinetoram (Radiant SC) at 0.023 to 0.047 lb ai/a. PHI 3 days forage or fodder; 28 days grain. REI 4 hr. Do not exceed 0.125 lb ai/a per year. Do not exceed 3 treatments. Retreatment interval 4 days.
  • spinosad (Success) at 0.047 to 0.094 lb ai/a. PHI 28 days grain or fodder; 7 days forage. REI 4 hr. Do not exceed 0.188 lb ai/a per season. OMRI-listed for organic use.
  • Spodoptera frugiperda MNPV-3AP2 (Fawligen, Spexit) at 1 to 2.5 fl oz product per acre. PHI 0 day. REI 4 hr. Beet armyworm and fall armyworm only.
  • tebuconazole/lambda-cyhalothrin (Crossover) at 0.14 to 0.16 lb ai/a. PHI 21 days fodder and silage. REI 24 hr. Retreatment interval 7 days. Do not exceed 0.48 lb ai/a tebuconazole or 0.12 lb ai/a lambda-cyhalothrin per season.
  • zeta-cypermethrin (Mustang) at 0.022 to 0.05 lb ai/a. PHI 7 days for grain, stover and forage. Do not exceed 0.2 lb ai/a per season. REI 12 hr. Retreatment interval 3 days.

Related Links

Kaur, N. (Ed.). 2023 Pacific Northwest Insect Management Handbook.
© Oregon State University.

Use pesticides safely!

  • Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
  • Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
  • Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.

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