1. Insect
  2. Agronomic Crops
  3. Small Grain Pests

Small grain-Cutworm and armyworm

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Darksided cutworm
Euxoa messoria Harris
Immature
© Ken Gray Insect Image Collection
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Bertha armyworm
Mamestra configurata Walker
Adult
© Ken Gray Insect Image Collection
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Variegated cutworm
Peridroma saucia Hubner
Newly hatched on host
© Ken Gray Insect Image Collection
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Variegated cutworm
Peridroma saucia Hubner
Adult
© Ken Gray Insect Image Collection
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Variegated cutworm
Peridroma saucia Hubner
Immature
© Ken Gray Insect Image Collection

Includes

Army cutworm (Chorizagrotis auxiliaris)
Black cutworm (Agrotis ipsilon)
Fall Armyworm (Spodoptera frugipedra)
Variegated cutworm (Peridroma saucia and Euxoa spp.)
Wheat head armyworm (Faronta diffusa)

Pest description and crop damage Young plants often are damaged in early spring. In recent years, growers in Washington and Idaho have made reports of these pests damaging barley and wheat crops. They feed on foliar tissue and can consume young seedlings to the ground. During the day, they hide in plant litter and/or just below the soil surface. Fall armyworm infestations in winter wheat have also been reported in south and southeastern Idaho in fall. There are no set thresholds and management recommendations depend on the stages of plant and larval development and the extent of the damage. More than 2-3 larger larvae (> 1/2in) per square foot may require control. Scout as many spots as possible within a field.

Management-chemical control

Foliar sprays

  • alpha-cypermethrin (Fastac EC) at 0.008 to 0.025 lb ai/A. PHI 14 days for grain, forage and hay. REI 12 hr. Retreatment interval 14 days. Do not exceed 0.075 lb ai/A per season. Wheat and triticale.
  • azadirachtin (Aza-Direct, Ecozin 3EC) at 0.0125 to 0.043 lb ai/A. PHI 0 days. REI 4 hr. Best results can be obtained following 2 to 3 applications made at 7- to 10-day intervals. Some formulations are OMRI-listed for organic use.
  • Bacillus thuringiensis kurstaki (Javelin) at 0.85 to 1.275 lb ai/A. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • beta-cyfluthrin (Baythroid XL) at 0.008 to 0.019 lb ai/A. PHI 30 days, 3 days for grazing or foraging. REI 12 hr. Retreatment interval 3 days. Do not exceed 0.038 lb ai/A per season.
  • Burkholderia spp. (Venerate XC) at 1 to 4 quarts/A. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • chlorantraniliprole (Coragen) at 0.045 to 0.098 lb ai/A. PHI 1 day. REI 4 hr. Retreatment interval 7 days. Do not exceed 0.2 lb ai of chlorantraniliprole per acre per year. Limit 4 treatments. Armyworms only.
  • Chromobacterium subtsugae (Grandevo WDG) at 0.3 to 0.9 lb ai/A. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • cyfluthrin (Tombstone) at 0.016 to 0.038 lb ai/A. PHI 30 days, 3 days for grazing or foraging. REI 12 hr. Retreatment interval 3 days. Do not exceed 0.076 lb ai/A per season of cyfluthrin alone, or the combined total of cyfluthrin plus beta-cyfluthrin. Wheat only.
  • gamma-cyhalothrin (Declare) at 0.0075 to 0.015 lb ai/A. PHI 30 days, 7 days for grazing or foraging. REI 24 hr. Do not exceed 0.03 lb ai/A per season.
  • GS-omega/kappa-Hxtx-Hv1a (Spear Biological Insecticide) at 0.17 to 0.34 lb ai/A. PHI 0 days. REI 4 hr. Do not exceed 5 applications or 1.7 lb ai/A per year. Must be tank mixed with Bacillus thuringiensis (Bt).
  • lambda-cyhalothrin (Silencer, Warrior II) at 0.015 to 0.03 lb ai/A. PHI 30 days, 7 days for grazing or foraging. REI 24 hr. Do not exceed 0.06 lb ai/A per season.
  • lambda-cyhalothrin/chlorantraniliprole (Besiege) at 0.049 to 0.078 lb ai/A. PHI 30 days, 7 days for grazing or foraging. REI 24 hr. Retreatment interval 7 days. Do not exceed 0.06 lb ai lambda-cyhalothrin or 0.2 lb ai chlorantraniliprole per year.
  • lambda-cyhalothrin/tebuconazole (Crossover) at 0.14 lb ai/A. PHI 30 days, 7 days for grazing or foraging. REI 24 hr. Do not exceed 0.11 lb ai/A tebuconazole or 0.06 lb ai/A lambda cyhalothrin per season. Do not exceed 8 fl oz/A or 0.139 lb ai/A per season. Barley, triticale and wheat.
  • lambda-cyhalothrin/thiamethoxam (Endigo ZC) at 0.056 to 0.072 lb ai/A. PHI 30 days, 7 days for grazing or foraging. REI 24 hr. Retreatment interval 7 days. Do not exceed 0.06 lb ai/A lambda-cyhalothrin or 0.125 lb ai/A thiamethoxam per season. Groundwater advisory. Barley only.
  • malathion (Malathion 8) at 1.0 lb ai/A. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Limit 2 treatments per year. Barley, oat, rye and wheat.
  • methomyl (Lannate SP) at 0.225 to 0.45 lb ai/A. PHI 7 days. REI 48 hr. Do not exceed 1.8 lb ai/A per season. Do not exceed 4 applications per season. Wheat only.
  • pyrethrin-There are several pesticides containing various amounts of pyrethrins. Check each label for the use and amount needed.. Some formulations are OMRI-listed for organic use.
  • spinetoram (Radiant SC) at 0.023 to 0.047 lb ai/A. PHI 21 days for grain and straw; 3 days for forage, fodder, or hay harvest. REI 4 hr. Retreatment interval 4 days. Do not exceed 0.141 lb ai/A per year. Limit 3 applications per year.
  • spinosad (Success, Entrust SC) at 0.047 to 0.094 lb ai/A. PHI 21 days for grain and straw; 3 days for forage, fodder or hay. REI 4 hr. Retreatment interval 4 days. Do not exceed 0.28 lb ai/A per year. Limit 3 treatments per year. Armyworms only. Entrust SC is OMRI-listed for organic use.
  • zeta-cypermethrin (Mustang) at 0.016 to 0.05 lb ai/A. PHI 14 days for grain, forage, and hay. REI 12 hr. Retreatment interval 14 days. Do not exceed 0.25 lb ai/A (0.125 lb ai/A for MustangMaxx) per year.