Pacific Northwest Insect Management Handbook

Field and silage corn-Corn earworm

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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) Group 3A insecticide 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.
  • Bacillus amyloliquefaciens D747 TGAI/bifenthrin (Ethos 3D, Ethos XB) at 0.04 to 0.2 lb bifenthrin ai/A. Do not exceed 0.3 lb bifenthrin on field corn per season. REI 12 hr. PHI Group 3A insecticide, Group 44 fungicide.
  • beta cyfluthrin (Baythroid XL) Group 3 insecticide at 0.013 to 0.022 lb ai/A (1.6 to 2.8 fl oz/A). PHI 0 days for green forage and 21 days for grain or fodder. REI 12 hr. Maximum 2.8 fl oz/A in 7-day interval. Do not exceed four applications or 0.088 lb ai/A per season.
  • bifenthrin (Brigade 2EC, Sniper) Group 3A insecticide at 0.033 to 0.1 lb ai/A (2.1 to 6.4 fl oz/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/chlorantraniliprole (Elevest) at 0.098 to 0.167 lb ai/A. REI 12 hr. PHI 30 days. No more than three applications per year. Do not apply more than a total of 0.2 lb ai/A of chlorantraniliprole and 0.3 lb ai/A of bifenthrin per year. Group 3A and 28. Apply ELEVEST insect control when silking begins and repeat as necessary to maintain control. To control western bean cutworm, apply at egg hatch before they move into the ear.
  • bifenthrin/zeta-cypermethrin (Hero) Group 3A insecticide at 0.04 to 0.1 lb ai/A (4.5 to 11.2 fl oz/A). PHI 30 days grain and stover; 60 days forage. REI 12 hr. Do not graze for 30 days after treatment. Do not exceed 0.1 lb ai/A at-plant application or 0.099 lb/A zeta-cypermethrin and 0.398 lb/A bifenthrin per year.
  • Burkholderia spp. (Venerate XC) bioinsecticide at 1 to 4 quarts/A. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • carbaryl (Sevin 4F) insecticide 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) Group 3 & 28 insecticide at 0.045 to 0.08 lb ai/A (5 to 10.0 fl oz/A). For control before larva bores into plant stalk or ear. 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) Group 28 insecticide 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.
  • Chromobacterium subtsugae (Grandevo) bioinsecticide at 0.6 to 0.9 lb ai/A per 100 gal (2.0 to 3.0 lb product /A). PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • cyfluthrin (Tombstone) insecticide at 0.025 to 0.044 lb ai/A (1.6 to 2.8 fl oz/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) Group 3 insecticide at 0.018 to 0.022 lb ai/A (1.5 to 1.9 fl oz/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. 5 lb ai/A. PHI 21 days. REI 12 hr. Do not exceed 0.25 lb ai/A per season.
  • esfenvalerate (Asana XL) Group 3 insecticide at 0.03 to 0.05 lb ai/A (5.8 to 9.6 fl oz/A). PHI 21 days. REI 12 hr. Do not exceed 0.25 lb ai/A per season.
  • gamma cyhalothrin (Declare) Group 3 insecticide 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 (biopesticide). OMRI-listed for organic use.
  • indoxacarb (Steward EC) Group 22 insecticide 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) Group 3 insecticide 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.
  • malathion (Drexel 5EC, Fyfanon 57EC, Fyfanon 8 lb Emulsion and several other formulations)-See label for rates. Rates may vary between formulations. PHI 7 days. REI 72 hr for detasseling, 12 hr for other activities. Group 1.
  • methomyl (Lannate SP) Group 1A insecticide 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) Group 5 and 18 insecticide 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) Group 5 insecticide 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) Group 5 insecticide 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.
  • tebuconazole/lambda-cyhalothrin (Crossover) Group 3 fungicide/insecticide 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) Group 3A insecticide 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.). 2024 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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