Onion-Armyworm and cutworm

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:

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. 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.
  • Beauveria bassiana-Some formulations are OMRI-listed for organic use.
  • cyhalothrin
  • deltamethrin
  • gamma-cyhalothrin
  • 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-derived essential oils (rosemary, peppermint etc.)-These have some 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

  • Bacillus thuringiensis (Javelin) at 0.12 to 1.5 lb/a. PHI 0 days. Small armyworms only. Use a spreader-sticker to enhance control. Some formulations are OMRI-listed for organic use.
  • chlorantraniliprole (Coragen) at 0.045 to 0.065 lb ai/a. PHI 1 day. REI 4 hr. Retreatment interval 14 days. Do not exceed 0.2 lb ai/a per season. Limit 4 treatments per season.
  • cypermethrin (Holster) at 0.04 to 0.1 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.5 lb ai/a per season. Do not graze or feed crop residues to livestock.
  • deltamethrin (Delta Gold) at 0.012 to 0.018 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 5 days. Do not exceed 0.112 lb ai/a per season.
  • gamma-cyhalothrin (Declare) at 0.0075 to 0.0125 lb ai/a for cutworms and 0.01 to 0.015 lb ai/a for armyworms. PHI 14 days. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.12 lb ai/a per season. An oil or nonionic surfactant improves control.
  • GS-omega/kappa (Spear Biological Insecticide) at 0.8 lb ai/a. PHI 0 days. REI 4 hr. Do not exceed 2 lb ai/a per year.
  • lambda-cyhalothrin (Warrior II) at 0.015 to 0.025 lb ai/a for cutworm; or 0.02 to 0.03 lb ai/a for armyworm. PHI 14 days. REI 24 hr. Retreatment interval 5 days. Do not graze or feed to livestock. Do not exceed 0.24 lb ai/a per season. An oil or surfactant adjuvant improves control.
  • methomyl (Lannate SP) at 0.45 to 0.9 lb ai/a. PHI 7 days. REI 48 hr. Do not exceed, per season, 5.4 lb ai/a on green onion and 3.6 lb ai/a on dry bulb onion. Limit 8 treatments per season. Retreatment interval 5 days.
  • methoxyfenozide (Intrepid 2F) at 0.06 to 0.12 lb ai/a for early season; 0.12 to 0.19 lb ai/a for mid- to late-season applications. PHI 1 day. REI 4 hr. Do not exceed 1 lb ai/a per season. Limit 6 treatments.
  • permethrin (Ambush 25WP, Pounce 25WP) at 0.15 to 0.3 lb ai/a for armyworm and 0.1 to 0.3 lb ai/a for cutworm. PHI 1 day. REI 12 hr. Do not exceed 2 lb ai/a per season. Do not feed culls or graze. Toxic to fish.
  • spinetoram (Radiant SC) at 0.039 to 0.078 lb ai/a. PHI 1 day. Retreatment interval 4 days. Do not exceed five applications or 0.234 lb ai/a per season. Follow resistance management procedures on the label.
  • spinosad (Success) at 0.047 to 0.094 lb ai/a. PHI 1 day. REI 4 hr. Retreatment interval 4 days. Do not exceed 0.45 lb i/a per season. Some formulations are OMRI-listed for organic use.
  • zeta-cypermethrin (Mustang) at 0.028 to 0.05 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.25 lb ai/a per year.