Pasture and grass hay-Grass scale (mealybug)

Eriococcus insignis

Pest description and crop damage On timothy hay or timothy-alfalfa mixed-stand hay crops only. This scale weakens stands. It can be a serious pest in western regions where it has become established. A serious pest in all of western Washington.

Management-chemical control

  • bifenthrin (Brigade WSB) at 0.05 to 0.1 lb ai/a. PHI 30 days for forage and hay. REI 12 hr. Retreatment interval 14 days. Do not exceed 0.2 lb ai/a per season.
  • chlorantraniliprole/lambda-cyhalothrin (Besiege, Voliam Xpress) at 0.59 to 0.98 lb ai/a. PHI 0 days for grazing or cut for forage; 7 days for cut grass to be dried and harvested for hay. Retreatment interval 7 days. REI 12 hr. Do not exceed 0.09 lb ai/a lambda-cyhalothrin or 0.2 lb ai/a chlorantraniliprole.
  • gamma-cyhalothrin (Declare) at 0.01 to 0.015 lb ai/a. PHI 0 days for grazing or cut for forage; 7 days for cut grass to be dried and harvested. REI 24 hr. Do not exceed 0.045 lb ai/a per season.
  • lambda-cyhalothrin (Warrior II) at 0.02 to 0.03 lb ai/a. PHI 0 days for grazing and forage; 7 days to be dried for hay. REI 24 hr. Do not exceed 0.03 lb ai/a per cutting or 0.09 lb ai/a per season.
  • zeta-cypermethrin (Mustang) at 0.028 to 0.05 lb ai/a. PHI 0 days graze and hay; 7 days straw. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.2 lb ai/a per season.