Pacific Northwest Insect Management Handbook

Field and silage corn-Cutworm

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Western bean cutworm
Loxagrotis albicosta Smith
Female adult
© Ken Gray Insect Image Collection
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Western bean cutworm
Loxagrotis albicosta Smith
Showing damage
© Ken Gray Insect Image Collection
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Western bean cutworm
Loxagrotis albicosta Smith
Newly hatched
© Ken Gray Insect Image Collection
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Black cutworm
Agrotis ipsilon Hugnagel
Adult
© Ken Gray Insect Image Collection

Includes

Black cutworm (Agrotis ipsilon)
Western bean cutworm (Loxagrotis albicosta)

Pest description and crop damage Brown to black larvae up to 1.5 inches at maturity. They clip seedlings and tunnel into the bases of older plants. Larvae are usually in soil at planting. Look for seedlings wilting, leaf cutting and missing plants.

Management-chemical control

  • alpha-cypermethrin (Fastac CS, Fastac EC) Group 3A insecticide at 0.008 to 0.018 lb ai/A or 0.001 lb ai/1,000 row ft as in furrow, band or T-band. 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.
  • azadirachtin (Neemix 4.5)-PHI 0 days. REI 12 hr. See label for rates. Slow acting. Apply early. Thorough coverage and repeat applications are necessary. Some formulations are OMRI-listed for organic use.
  • 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 0.007 to 0.013 lb ai/A (0.8 to 1.6 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, Capture LFR) Group 3A insecticide at 0.033 to 0.1 lb ai/A foliar, 0.0023 to 0.0046 lb ai/1,000 row ft at plant, 0.047 to 0.062 lb ai/A preplant incorporated, or 0.04 lb ai/A preemergence. PHI 30 days for harvest, grazing, or cutting for feed. REI 12 hr. Do not apply more than 0.1 lb ai/A as an at-plant application. Apply Brigade 2EC in a minimum of 3 gal finished spray per acre. Do not apply Capture LFR as foliar treatment.
  • bifenthrin/chlorantraniliprole (Elevest) at 0.084 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.
  • bifenthrin/chlorethoxyfos Group 1B insecticide
  • SmartChoice 5G application rate of 3.0 to 3.5 oz/100 ft. REI 2 days or 3 days where annual rainfall is less than 25 inches. T-band over the row or apply in furrow. Apply with Smartbox system. Do not exceed one application per year.
  • SmartChoice HC application rate at 1.15 to 1.67 oz/1,000 row ft. See spacing charts in label for actual application rates per A. REI 2 days or 3 days where annual rainfall is less than 25 inches. T-band over the row or apply in furrow. Apply with Smartbox system. Do not exceed one application per year.
  • bifenthrin/zeta-cypermethrin (Hero, Hero EW) Group 3A insecticide at 0.04 to 0.10 lb ai/A (4.5 to 11.2 fl oz/A) see label for specifics on lb per linear ft based on row spacing. PHI 30 days grain and stover; 60 days forage. REI 12 hr. Do not graze for 30 days after treatment. Do not exceed 0.099 lb/A zeta-cypermethrin and 0.398 lb/A bifenthrin per year..
  • carbaryl (Sevin 4F, Sevin 5 Bait)-Apply bait or spray at 2 lb ai/A. PHI 14 days for harvest or grazing forage or silage, and 48 days for grain or fodder harvest. REI 24 hr. Do not exceed four applications per season. Early season applications when plants are 6 to 12 inches high should be directed to the lower stalk portions and soil around the plant bases. Do not use if bees are foraging actively in the field.
  • chlorantraniliprole/lambda-cyhalothrin (Besiege) Group 3 & 28 insecticide at 0.045 to 0.098 lb ai/A (6.0 to 10.0 fl oz/A). PHI 21 days. REI 24 hr. Do not exceed 0.12 lb ai of lambda-cyhalothrin or 0.2 lb ai/A of chlorantraniliprole per growing season. Retreatment interval 7 days.
  • chlorethoxyfos/bifenthrin (SmartChoice 5G, Smartchoice HC) Group 1B insecticide-Apply SmartChoice 5G at 4.5 to 5.0 oz per 1,000 row ft; Smartchoice HC application rate of 1.0 to 1.67 oz / 100 ft row. REI 2 days or 3 days where annual rainfall is less than 25 inches. T-band over the row or apply in-furrow. Apply with Smartbox system. Do not exceed one application per year.
  • 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 (2 to 3 lb/A). REI 4 hr. OMRI-listed for organic use.
  • cyantraniliprole (Fortenza) at 0.125 to 0.5 lb ai/seed. REI 12 hr. Do not exceed 0.4 lb ai/A of cyantraniliprole products per year.
  • cyfluthrin (Tombstone) insecticide at 0.013 to 0.025 lb ai/A (0.8 to 1.6 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 0.012 to 0.018 lb ai/A (1.0 to 1.5 fl oz/A). PHI 21 days for grain or fodder or 12 days for forage or grazing. REI 12 hr. Re-treatment interval is 21 days. Do not exceed 0.095 lb ai/A per season. Retreatment interval 21 days. Limit 5 treatments per year.
  • esfenvalerate (Asana XL) Group 3 insecticide at 0.03 to 0.05 lb ai/A (5.8 to 9.6 fl oz/A), foliar or 0.0023 lb per 1,000 row ft at plant. PHI 21 days. REI 12 hr.
  • ethoprop (Mocap 15G) nematicide/insecticide at 3.0 lb ai/A broadcast three days before planting to planting time. REI 48 hr or 72 hr where annual rain is less than 25 inches. One application per season. Mix with the top two inches of soil.
  • gamma-cyhalothrin (Declare) Group 3 insecticide at 0.0025 lb ai/1,000 row ft at plant; 0.0075 to 0.0125 lb ai/A foliar application. PHI 1 day for grazing and forage, or 21 days for fodder or silage. REI 24 hr. Do not exceed 0.06 lb ai/A per season.
  • lambda-cyhalothrin (Warrior II) Group 3 insecticide at 0.015 to 0.025 lb ai/A foliar or 0.005 lb ai/1,000 row ft at planting. PHI 21 days. REI 24 hr. Do not apply more than 0.12 lb ai/A at plant and foliar applications per season, 0.06 lb ai/A after silk initiation, or 0.03 lb ai/A after milk stage.
  • methomyl (Lannate SP) Group 1A insecticide at 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. Retreatment interval 5 to 7 days.
  • methoxyfenozide (Intrepid 2F) Group 18 insecticide at 0.06 to 0.25 lb ai/A. PHI 21 days. REI 4 hr. Do not exceed 1 lb ai/A per season. Western bean cutworm only.
  • methoxyfenozide/spinetoram (Intrepid Edge) at 0.188 to 0.281 lb ai/A. Specific to western bean cutworm. 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. Group 5 and 18 insecticide.
  • permethrin-Group 3 insecticides:
    • Ambush 25W at 0.1 to 0.2 lb ai/A foliar or as preemergent. PHI 0 days for forage harvest or 30 days for grain harvest or fodder. REI 12 hr. Allow 6 days between applications. Do not apply more than 0.6 lb ai/A per season.
    • Loveland Permethrin Cutworm Bait at 0.1 to 0.15 lb ai/A. REI 12 hr. PHI 0 days for forage; 30 days for grain harvest or fodder. Retreatment interval 7 days. Do not exceed 0.45 lb ai/A per season.
    • Pounce 1.5G at 0.0075 to 0.015 lb ai/1,000 row ft soil or 0.1 to 0.15 lb ai/A broadcast. Apply in furrow or as band at planting. PHI 0 days for forage harvest or 30 days for grain harvest or fodder. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.45 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. Western bean cutworm only.
  • 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. Western bean cutworm only.
  • 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.
  • tefluthrin (Force 3G) Group 3 insecticide at 0.0056 to 0.075 lb ai/1,000 row ft. T-band or in-furrow at planting. REI 0 days.
  • zeta-cypermethrin (Mustang) Group 3A insecticide at 0.016 to 0.035 lb ai/A foliar. PHI 7 days for grain, stover and forage. REI 12 hr. Do not exceed 0.2 lb ai/A per season.

Seed treatments

  • clothianidin (Poncho)-Commercial treaters only. See label instructions.
  • clothianidin/Bacillus firmus (Poncho Votivo) at 0.5 mg ai/seed. Do not exceed 0.5 mg ai/seed.
  • thiamethoxam/Abamectin/Azoxystrobin (Avicta Complete). Refer to label instructions.

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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