Includes:
Bertha armyworm (Mamestra configurata)
Variegated cutworm (Peridroma saucia)
Pest description and crop damage These larvae vary a lot in color. By day, larger larvae can be found in soil cracks or under duff or leaves; they commonly feed at night. Smaller larvae are visible on foliage during the day and can be sampled with a sweep net. They cut off young plants and feed on the foliage of older plants.
Management-chemical control
- azadirachtin (Aza-Direct, Atrevia 3% SL)-Aza-Direct at 0.015 to 0.021 lb ai/A; Atrevia 3% SL at 0.015 to 0.03 lb ai/A. REI 4 hr. PHI 0 days. OMRI-listed for organic use.
- Bacillus thuringiensis (Xentari, Biobit, BT NOW, Javelin)-Xentari and Biobit at 0.5 to 2 lb product/A; BT NOW at 1 to 3.5 pints/A; Javelin at 0.25 to 1.5 lb product/A. PHI 0 days. REI 4 hr. Armyworms only. Add an appropriate spreader-sticker to enhance control. Most effective on small, actively feeding larvae. OMRI-listed for organic use.
- carbaryl (Drexel Carbaryl 4L, Carbaryl 4L, Sevin XLR) at 1 to 1.5 lb ai/A. PHI 7 days before harvest or grazing. Use only once per cutting. REI 12 hr. Do not use carbaryl when clover is blooming or when bees are foraging actively.
- Chromobacterium subtsugae (Grandevo) at 1 to 3 lb product per 100 gal/Acre. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
- malathion (Drexel Malathion 5EC, Malathion 57 EC, Fyfanon 57% EC, Martin's Malathion 57%, Gowan Malathion 8, Malathion 8-E)- Drexel Malathion 5EC, Malathion 57 EC, Fyfanon 57% EC, Martin's Malathion 57% at 1.25 lb ai/A; Gowan Malathion 8, Malathion 8-E at 1 to 1.25 lb ai/A. PHI 0 days. Limit 2 treatments per cutting. Retreatment interval 14 days. REI 12 hr.
- spinosad (Entrust SC, Kibosh SC, Estero SC) at 0.031 to 0.062 lb ai/A. PHI 0 days forage; 3 days hay and fodder. REI 4 hr. Limit 6 treatments per year. Do not exceed 0.186 lb ai/A per season. Do not apply more than three times in a 21-day period. Do not graze cattle until spray has dried. Some formulations are OMRI-listed for organic use. Applying spinosad early in the season when the larvae are small leads to more effective control and reduces the need for additional applications
- zeta-cypermethrin (Mustang, Mustang Maxx, Cortes MAXX)-Mustang at 0.035 to 0.05 lb ai/A; Mustang Maxx or Cortes MAXX at 0.0175 to 0.025 lb ai/A. PHI 3 days for cutting or grazing; 7 days for seed. REI 12 hr. Do not apply more than 0.05 lb ai per cutting or 0.15 lb ai per season of Mustang or 0.025 lb ai per cutting and 0.075 lb ai per season of Mustang Maxx. Retreatment interval 7 days.