Pacific Northwest Insect Management Handbook

Lettuce-Armyworm and cutworm

  • Facebook logo
Image related to Lettuce-Armyworm and cutworm
Variegated cutworm
Peridroma saucia Hubner
Newly hatched on host
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Bertha armyworm
Mamestra configurata Walker
Immature
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Beet armyworm
Spodoptera exigua Hubner
Immature female adult
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Beet armyworm
Spodoptera exigua Hubner
Egg(s) on host
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Black cutworm
Agrotis ipsilon Hugnagel
Adult
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Variegated cutworm
Peridroma saucia Hubner
Immature
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Beet armyworm
Spodoptera exigua Hubner
Adult
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Western yellowstriped armyworm
Spodoptera praefica Grote
Young immature showing damage on leaves
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Western yellowstriped armyworm
Spodoptera praefica Grote
Egg(s) on host
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Western yellowstriped armyworm
Spodoptera praefica Grote
Adult
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Variegated cutworm
Peridroma saucia Hubner
Adult
© Ken Gray Insect Image Collection
Image related to Lettuce-Armyworm and cutworm
Bertha armyworm
Mamestra configurata Walker
Adult
© Ken Gray Insect Image Collection

Includes

Beet armyworm (Spodoptera exigua)
Bertha armyworm (Mamestra configurata)
Western yellowstriped armyworm (Spodoptera praefica)
Black cutworm (Agotis ipsilon)
Variegated cutworm (Peridroma saucia)

Pest description, crop damage and life history

See:

Common Pests of Vegetable Crops

Management-cultural control

Weed control is important. Lambsquarters and wild mustard attract egg-laying females and provide a source of food for larvae. Fall tillage can help destroy overwintering pupae.

Home gardeners: Control weeds, grasses, and debris in the vegetable garden that provide cover; hand-pick cutworm larvae, using a flashlight to find them, if practical. Scratch the soil at the base of plants to find larvae in the daytime.

Management-chemical control: HOME USE

Apply any one of these materials to the soil surface at first sign of cutworm activity. Consult label. Minimum preharvest interval (PHI) varies with crop. Difficult to control. Where cutworms are on the soil surface, a carbaryl drench, when bees are not present, may help.

  • acetamiprid
  • azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
  • Bacillus thuringiensis var. kurstaki (Btk)-Some formulations are OMRI-listed for organic use.
  • bifenthrin (often as a mix with zeta-cypermethrin).
  • carbaryl
  • cyfluthrin
  • gamma-cyhalothrin
  • insecticidal soap-Some formulations are OMRI-listed for organic use.
  • kaolin-When applied as a spray to foliage and stems it acts as a repellent to some insect pests. Some formulations are OMRI-listed for organic use.
  • lambda-cyhalothrin
  • permethrin
  • plant essential oils (rosemary, etc.)-Some have demonstrated efficacy against lepidopteran larvae. Some formulations are OMRI-listed for organic use.
  • pyrethrins-Some formulations are OMRI-listed for organic use.
  • spinosad-Some formulations are OMRI-listed for organic use.
  • zeta-cypermethrin

Management-chemical control: COMMERCIAL USE

  • acephate (Acephate 90WDG) at 1 lb ai/a. PHI 21 days. REI 24 hr. Armyworm only. Crisp head lettuce only. Retreatment interval 7 days. Limit treatments per year. Do not exceed 2 lb ai/a per season. Do not graze or feed treated plants.
  • alpha-cypermethrin (Fastac EC) at 0.014 to 0.025 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.075 lb ai/a per season.
  • azadirachtin (Neemix 4.5) at 0.14 to 0.35 lb ai/a. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • Bacillus thuringiensis (Javelin) at 0.12 to 1.5 lb/a. PHI 0 days. REI 4 hr. Acts slowly; may need multiple applications. Add an appropriate spreader-sticker to enhance control. Most effective on small larvae. Some formulations are OMRI-listed for organic use.
  • beta-cyfluthrin (Baythroid XL) at 0.007 to 0.025 lb ai/a. PHI 0 days. REI 12 hr. Do not exceed 0.1 lb ai/a per season. Retreatment interval 7 days.
  • bifenthrin/avermectin (Athena) at 0.048 to 0.116 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Head lettuce only. Do not exceed 0.056 lb ai/a avermectin or 0.5 lb ai/a bifenthrin per season.
  • beta-cyfluthrin/imidacloprid (Leverage 360) at 0.07 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.1 lb ai/a beta-cyfluthrin or 0.2 lb ai/a imidacloprid per season.
  • bifenthrin (Brigade 2EC) at 0.033 to 0.1 lb ai/a. PHI 7 days. REI 12 hr. Head lettuce only. Do not exceed 0.5 lb ai/a per season. Retreatment interval 7 days.
  • bifenthrin/imidacloprid (Brigadier) at 0.08 to 0.095 lb ai/a. PHI 7 days. REI 12 hr. Do not exceed 0.24 lb ai/a imidacloprid and 0.5 lb ai/a bifenthrin. Retreatment interval 7 days.
  • bifenthrin/zeta-cypermethrin (Hero EW) at 0.04 to 0.1 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.45 lb ai/a per season. Head lettuce only.
  • borate complex (Prev-Am Ultra) apply as 0.8% solution. Spray to complete coverage. REI 12 hr. OMRI-listed for organic use.
  • Burkholderia spp. (Venerate XC) at 1 to 4 quarts/a product. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • carbaryl (Sevin 4F) at 1 to 2 lb ai/a. PHI 14 days. REI 12 hr. Do not exceed 6 lb ai/a per season. Retreatment interval 7 days. Limit 5 treatments per year. Armyworm only.
  • chlorantraniliprole (Coragen) at 0.045 to 0.098 lb ai/a soil or foliar. PHI 1 day. REI 4 hr. Do not exceed 0.8 lb ai/a chlorantrniliprole per season. Retreatment intervals 3 days foliar, 10 days drip chemigation. Limit 4 treatments.
  • chlorantraniliprole/lambda-cyhalothrin (Voliam Xpress) at 0.058 to 0.088 lb ai/a. PHI 1 day. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.3 lb ai of lambda-cyhalothrin or 0.2 lb ai of chlorantraniliprole per acre per growing season.
  • chlorantraniliprole/thiamethoxam (Voliam Flexi) at 0.1 to 0.172 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.172 lb ai of thiamethoxam or 0.2 lb ai of chlorantraniliprole per acre per growing season
  • Chromobacterium subtsugae (Grandevo) at 0.3 to 0.9 lb ai/a per 100 gal. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • cyantraniliprole (Exirel) at 0.045 to 0.088 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 5 days. Do not exceed 0.4 lb ai/a per year.
  • cyclaniliprole (Harvanta 50SL) at 0.036 to 0.054 lb ai/a. PHI 1 day. REI 4 hr. Retreatment interval 5 days. Do not exceed 0.22 lb ai/a per year.
  • cyfluthrin (Tombstone) at 0.013 to 0.05 lb ai/a. PHI 0 days. REI 12 hr. Do not exceed 0.2 lb ai/a per season. Retreatment interval 7 days.
  • cyfluthrin/imidacloprid (Leverage 2.7) at 0.08 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.17 lb ai/a cyfluthrin or 0.24 lb ai/a imidacloprid per year.
  • cypermethrin (Holster) at 0.05 to 0.1 lb ai/a. PHI 5 days. REI 12 hr. Retreatment interval 7 days. Head lettuce only. Do not exceed 0.5 lb ai/a per season.
  • diazinon (Diazinon 50W) at 2 lb ai/a. Broadcast just before planting and incorporate. PHI 14 days. REI 3 days. Cutworms only.
  • emamectin benzoate (Proclaim) at 0.008 to 0.015 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.09 lb ai/a per season. Do not graze.
  • gamma-cyhalothrin (Declare) at 0.0075 to 0.015 lb ai/a. PHI 1 day. REI 24 hr. Do not exceed 0.15 lb ai/a per season. Adding an oil or nonionic surfactant improves performance.
  • indoxacarb (Avaunt) at 0.065 to 0.11 lb ai/a. PHI 3 days. REI 12 hr. Use of wetting agent recommended. Retreatment interval 3 days. Do not exceed 0.44 lb ai/a per season. Armyworm only.
  • lambda-cyhalothrin (Warrior II) at 0.015 to 0.03 lb ai/a. PHI 1 day. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.3 lb ai/a per season.
  • lambda-cyhalothrin/thiamethoxam (Endigo ZC) at 0.064 to 0.072 lb ai/a. PHI 7 days. REI 24 hr. Retreatment interval 7 days. Do not exceed 0.3 lb ai/a of lambda-cyhalothrin or 0.172 lb ai/a of thiamethoxam per season.
  • methomyl (Lannate SP) at 0.45 to 0.9 lb ai/a. PHI 7 days at low rate; 10 days at high rate. REI 48 hr. Retreatment interval 2 days. Do not exceed 3.6 lb ai/a on leaf or 7.2 lb ai/a on head lettuce per season.
  • methoxyfenozide (Intrepid 2F) at 0.06 to 0.12 lb ai/a early season and 0.12 to 0.16 lb ai/a mid to late season. PHI 1 day. REI 4 hr. Do not exceed 1 lb ai/a per season.
  • permethrin (Loveland Permethrin) at 0.1 to 0.2 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.8 lb ai/a per season. Beet armyworm only.
  • spinetoram (Radiant SC) at 0.039 to 0.078 lb ai/a. PHI 1 day. REI 4 hr. Retreatment interval 4 days. Do not exceed 0.266 lb ai/a per season. Limit 6 treatments per season. Do not apply to seedling leafy vegetables grown for transplant within a greenhouse, shade house, or field plot. Armyworms only.
  • spinosad (Success, Entrust SC) at 0.063 to 0.125 lb ai/a. PHI 1 day. REI 4 hr. Armyworms only. Do not exceed six applications or 0.45 lb ai/a per crop. Entrust SC is OMRI-listed for organic use.
  • Spodoptera frugiperda (Fawligen) at 1 to 2.4 fl oz product per acre. PHI 0 day. REI 4 hr. Beet armyworm only.
  • tebufenozide (Confirm 2F) at 0.09 to 0.12 lb ai/a early-year; 0.12 lb ai/a mid- to late-year. PHI 7 days. REI 4 hr. Do not exceed 0.12 lb ai/a per application or 0.625 lb ai/a per season. Reapplication on a 10- to 14-day schedule may be necessary for heavy infestations.
  • thiamethoxam/chlorantraniliprole (Durivo) at 0.195 to 0.257 lb ai/a soil. PHI 30 days. REI 12 hr. Do not exceed 0.257 lb ai/a per season.
  • zeta-cypermethrin (Mustang) at 0.028 to 0.05 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.3 lb ai/a per season.

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.

Trade-name products and services are mentioned as illustrations only. This does not mean that the participating Extension Services endorse these products and services or that they intend to discriminate against products and services not mentioned.