1. Insect
  2. Hay and Pasture Crops
  3. Pasture and Grass Hay Pests

Pasture and grass hay-Cereal leaf beetle

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Adult cereal leaf beetle is 4 to 5 mm long

Michael Bush, WA State University Extension

Cereal leaf beetle larva and the characteristic damage it causes to wheat and pasture grasses.

Michael Bush, WA State University Extension

Oulema melanopus

Pest description and crop damage The cereal leaf beetle is a quarantine pest with adults measuring 0.25 inch in length, with a brightly colored, orange-red thorax, yellow legs, and metallic-blue head and elytra (forewings). While damage to pasture grasses is rare, its presence has led to strict interstate movement regulations in states like California. Only grass hay from cereal leaf beetle-free PNW counties or fumigated hay from infested counties is allowed into California. Feeding by both the adults and larvae can lead to "windowpaning" on leaves, reducing photosynthesis and plant vigor.

Management-chemical control

  • beta-cyfluthrin (Baythroid XL, Cryptoid XL, Sultrus) 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 2EC, Discipline 2EC, Sniper, Bifenture EC, Discipline 2EC, Lancer 2EC) 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 year.
  • carbaryl (Drexel Carbaryl 4L, Carbaryl 4L, Sevin XLR ) 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 0.0391 to 0.0652 lb ai/A for chlorantraniliprole and 0.0195 to 0.0325 lb ai/A for lambda-cyhalothrin. 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, Lambda-Cy EC, Ravage II, Lamcap II, Crusader 2ME) 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.