Alfalfa seed-Webworm

Includes beet webworm (Loxostege sticticalis)

Pest description and crop damage Caterpillars vary from light to dark with three white longitudinal stripes and many black and white tubercles.

Management-chemical control

  • chlorantraniprole (Coragen) at 0.045 to 0.065 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 0.75 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 0.0075 to 0.0125 lb ai/A. PHI 1 day for forage, 7 days for hay. REI 24 hr. Do not exceed 0.06 lb ai/A per season 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.
  • indoxacarb (Steward EC) at 0.065 to 0.11 lb ai/A. REI 12 hr. PHI 7 days. Make no more than one application per season. Do not apply when bees are in the area. Chemigation applications through center pivot is permitted.
  • 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.
  • 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.