Includes
Bertha armyworm (Mamestra configurata)
Western yellowstriped armyworm (Spodoptera praefica)
Pest description and crop damage Caterpillars are 1.5 to 2 inches long when mature. Color varies within a species and within larvae in a field. They may be velvety black-with two prominent and several fine, bright yellow stripes on the sides-to plain green. Both species may be found on foliage during the day as well as night.
Management-chemical control
- Bacillus thuringiensis kurstaki (Deliver) at 0.25 to 1.5 lb product/A. PHI 0 days. REI 4 hr. Most effective on small caterpillars; use highest recommended rate for fully developed ones. A spreader-sticker may improve performance.
- chlorantraniliprole (Coragen) at 0.045 to 0.098 lb ai/A. PHI 0 days. REI 4 hr. Make no more than 4 applications per acre per crop. Do not make more than one application per cutting. Do not apply more than 15.4 fl oz Coragen or 0.2 lb ai of chlorantraniliprole per acre per crop.
- chlorpyrifos (Chlorpyrifos 4E-AG) at 0.5 to 1 lb ai/A. REI 24 hr. Application rates will vary depending on the nozzle droplet type. Toxic to fish, aquatic invertebrates, small mammals and birds. Highly toxic to bees. Buffer zones must be utilized for aquatic areas when using ground boom (25 ft), chemigation (25 ft), orchard airblast (50 ft), and aerial (150 ft). Do not cut or graze alfalfa within 7 days after application of 0.5 pint/acre, 14 days after application of 1 pint, and 21 days after application of > 1 pint/A. Labeled for Idaho.
- gamma-cyhalothrin (Proaxis, Declare) at 0.01 to 0.015 lb ai/A. PHI 1 day for forage, 7 days for hay. REI 24 hr. Do not exceed 0.06 lb ai/A per cutting or 0.015 lb ai/A per cutting. Do not apply on ground within 25 ft of aquatic habitat, 150 ft if applied by air, or 450 ft if applied from ULV.
- lambda-cyhalothrin (Serpent 1EC, Warrior II) at 0.02 to 0.03 lb ai/A. PHI 1 day for forage, 7 days for hay. REI 24 hr. Do not apply more than 0.03 lb ai (3.84 fl oz or 0.24 pint of product) per acre per cutting, or more than 0.12 lb ai (15.36 fl oz or 0.96 pint of product) per acre per season. Do not apply on ground within 25 ft of aquatic habitat (groundboom, overhead chemigation, or airblast), 150 ft if applied by air, or 450 ft if applied from ULV. Do not apply while bees are active. Advisable to move bee shelters for 2 to 3 days after application. Avoid application when bees are actively foraging by applying during the early morning or during the evening hours.
- lambda-cyhalothrin + chlorantraniliprole (Besiege) at 0.03 to 0.06 lb ai/A. PHI 1 day for forage and 7 days for hay. Do not exceed a total of 31.0 fl oz per year. Do not apply more than 10.0 fl oz per acre per cutting and no more than 1 application per cutting. Avoid application when bees are actively foraging by applying during the early morning or during the evening hours. It may be advisable to remove bee shelters during and for 2 to 3 days following application. Avoid direct application to bee shelters.
- malathion 8EC at 1.0 to 1.25 lb ai/A. PHI 0 days. REI 12 hr. Not effective below 65ºF. Not recommended for fields pollinated with leafcutting bees. WA only.
- permethrin at 0.05 to 0.2 lb ai/A. PHI 0 days at rates equal to or less than 0.1 lb ai/A, 30 days at rates greater than 0.1 lb ai/A. REI 12 hr. Do not reapply at less than 7-day intervals or exceed 0.2 lb ai/A per cutting. If used during bloom, remove bees from field for 3 days. Do not apply on ground within 25 ft of aquatic habitat, 100 ft if applied by air, or 450 ft if applied from ULV.
- zeta-cypermethrin (Mustang Max) at 0.014 to 0.025 lb ai/A. PHI 3 days for cutting or grazing, 7 days for harvest. REI 12 hr. Allow at least 7 days between applications. Do not exceed 0.05 lb ai/A per cutting or 0.15 lb ai/A per year. Do not apply on ground within 25 ft of aquatic habitat, 150 ft if applied by air, or 450 ft if applied from ULV.