Alfalfa seed-Lygus bug

Includes Lygus spp.

Pest description and crop damage Adults are 0.18 inch long and have a light yellow V on the back. Lygus bugs pierce buds and suck sap, injuring both vegetative and reproductive buds. Damage includes blasted buds, blossom drop, and shriveled seed.

Management-chemical control

First application-Apply insecticides on warm days in late May as populations approach three per sweep and appear to be increasing. Use at least 10 gal/a spray in aerial applications.

Second application-May need to reapply during bloom if lygus bugs (adults plus nymphs) reach three to four per 180° sweep of a 15 inch net but before most of the nymph field population reach fourth instar. Use bifenthrin (Capture 2EC). Naled (Dibrom) is not recommended during early season if leafcutting or alkalai bees are active. Capture 2EC (bifenthrin) at the lower label rate tends to be least destructive to beneficials.

  • bifenthrin (Brigade 2ECor Discipline 2EC) at 0.06 to 0.1 lb ai/a. REI 12 hr. Do not apply more than three times per season or at intervals less than 21 days. May not be used for hay, forage, or human consumption. Do not apply at ground level within 25 ft of aquatic habitat, 150 ft if applied by air. 24c SLN ID-070009 and 040009; OR-070011 and 040039; WA-070015 and 040027.
  • dimethoate 4EC at 0.25 to 0.5 lb ai/a. PHI 10 days. REI 48 hr. Do not apply if crop or weeds are in bloom. Effective only on cutting to which chemical is applied. Do not feed or graze livestock.
  • flonicamid (Beleaf) at 0.0875 lb ai/a. PHI not given on label. REI 12 hr. This product will also suppress aphids. Do not apply more than 2 applications at this rate closer than 7 days apart per crop year. 30 day plant back restriction. SLN OR-070023; ID 070014; WA-070013b; NV-070007; UT-07-0007; WY-080009.
  • formetanate hydrochloride (Carzol SP) at 0.46 to 0.92 lb ai/a. PHI 21 days. REI 4 days. Do not apply during bloom and do not exceed 0.92 lb ai/a per season. Do not use any crop part as feed. Treated fields must be cleared after harvest by burning or disking.
  • 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 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.
  • lambda-cyhalothrin (Warrior) at 0.02 to 0.03 lb ai/a. PHI 1 day for forage, 7 days for hay. REI 24 hr. Do not exceed 0.03 lb ai/a per cutting or 0.12 lb ai/a per season. Do not apply on ground within 25 ft of aquatic habitat, 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.
  • malathion 8EC at 0.75 to 1.25 lb ai/a. PHI 0 days. REI 12 hr. Not effective below 65°F.
  • naled (Dibrom 8E) 1.0 to 1.5 lb ai/a. PHI not given. REI 48 hr for 1 lb ai/a or less, 72 hr for rates greater than 1 lb ai/a. Allow at least 7 days between applications. Do not apply during bloom nor exceed three applications per season. No part of treated field may be used as feed. SLN ID-010017; OR-990032; WA-990028.
  • permethrin at 0.1 to 0.2 lb ai/a. PHI 0 days at rates equal to or less than 0.1 lb ai/a, 14 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.
  • zeta-cypermethrin (Mustang) at 0.035 to 0.05 lb ai/a. PHI 3 days for cutting or grazing, 7 days for harvest. REI 12 hr. Allow at least 7 days between treatments. Do not exceed 0.05 lb ai/a per cutting or 0.15 lb ai/a per season. Do not apply on ground within 25 ft of aquatic habitat, 150 ft if applied by air or 450 ft if applied from ULV.

Resistance management Growers are advised strongly to rotate insecticide families (i.e., organophosphates, carbamates, and synthetic pyrethroids) in their lygus control programs to help prevent developing insecticide resistance.