Pasture and grass hay-Black grass bug

Labops hesperius and other Labops spp.
Irbisia pacifica and other Irbisia spp.

Pest description and crop damage Insect is grayish black with silvery scales, about 0.25 inch long, and somewhat pear-shaped. Adults have prominent compound eyes and can have shortened or absent wings. Black grass bugs will feed on a variety of range grasses (e.g., wheatgrass, brome grass, orchardgrass, bluegrass) and field crops (e.g., barley, wheat, rye, oats). Great Basin wildrye and wheatgrasses are preferred if available, especially blue bunch wheatgrass, crested wheatgrass, and intermediate wheatgrass. Feeding causes pale spots on the leaves of cereals and, when severe, a general yellowish, stippled appearance.

Management-chemical control

  • carbaryl (Sevin 4F) at 0.5 to 1 lb ai/a. PHI 14 days. REI 12 hr. Limit 2 treatments per year. Retreatment interval 14 days. Do not exceed 3 lb ai/a per year. (see various labels under "rangeland").
  • 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 0.015 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. Do not exceed 0.2 lb ai/a per season.