Scouting for pests: Blister beetle

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included

Blister beetle adults are 19 mm long and elongated. They vary in color from black and blue to brown, with or without stripes (view photos). They possess a characteristic constricted neck. These beetles overwinter as larvae in the soil. Adults feed on flowers and leaves, creating small rounded or irregularly shaped holes.


Adults can be hand picked, but it is important to wear gloves because these insects release a caustic substance when crushed that can cause blisters and welts on the skin. Contact insecticides may be used to control the adults.

Individual plants can be sprayed with Sevin (carbaryl) to protect them from grasshopper or blister beetle damage.  Repeat sprays may be needed if blister beetles or grasshoppers continue to move to sprayed plants from the surrounding area.

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