Pasture and grass hay-Cereal leaf beetle

Oulema melanopus

Pest description and crop damage Adults are 0.25 inch long with a brightly colored, orange-red thorax, yellow legs, and metallic-blue head and elytra (forewings). This is a quarantine pest, and although damage is seldom seen in pasture grasses, California has strict import laws governing interstate movement of pasture hay from counties in other states known to be infested with CLB. Only grass hay from cereal leaf beetle-free PNW counties or fumigated hay from infested counties is allowed into California.

Management-chemical control

  • beta-cyfluthrin (Baythroid XL) at 0.013 to 0.015 lb ai/A. PHI 0 days for grazing or hay. REI 12 hr. Do not exceed 0.089 lb ai/A per season. Retreatment interval 5 days.
  • 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.
  • carbaryl at 1 lb ai/A. PHI 14 days. REI 12 hr. Do not exceed two applications. Retreatment interval 14 days. This pest does not occur on the carbaryl labels but when this general use insecticide is applied to control other pests when CLB is present, control is good.
  • chlorantraniliprole/lambda-cyhalothrin (Besiege, Voliam Xpress) at 0.059 to 0.098 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.
  • malathion (Malathion 5EC) at 1.25 lb ai/A. PHI 0 days. REI 12 hr. One application limit per cutting.
  • zeta-cypermethrin (Mustang, Mustang Maxx) Mustang at 0.035 to 0.05 lb ai/A; Mustang Maxx at 0.0175 to 0.025 lb ai/A. PHI 3 days for cutting and grazing; 7 days for seed. REI 12 hr. Do not apply more than 0.05 lb ai per cutting or 0.15 lb ai per season of Mustang or 0.025 lb ai per cutting and 0.075 lb ai per season of Mustang Maxx. Retreatment interval 7 days.