Extension > Garden > Diagnose a problem > What insect is this? > Garden Pests > Beetles, bugs, ants, and other insects without obvious wings - 1/4 inch - 1/2 inch long > Bean leaf beetle

Bean leaf beetle

Cerotoma trifurcata

Jeff Hahn, University of Minnesota Extension

Jeff Hahn, University of Minnesota Extension

Description: 1/4 inch long.
Color varies from yellow to green to orange to red; four medium sized and two smaller black spots along with a black margin on the wing covers are usually present but this can vary. All beetles have a black triangle located at the top of the wing covers.

Where/When: Feeds on leaves of snap peas (string peas, green beans). Also, on soybean, clover, and other legumes. Adults are active mid-May to early June and mid-July through September.

Significance: Low numbers usually not injurious. High numbers can defoliate plants and kill young seedlings; they can also reduce vigor and yield of plants. Feeding on bean pods later in season is usually just cosmetic.

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