University of Illinois Extension
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Cucumber Beetles - Cucurbits


There are two types (striped and spotted) of cucumber beetles, which attack cucumbers, squash, and melons. Striped cucumber beetle is more common in Illinois than spotted cucumber beetle. Striped cucumber beetle adults overwinter in protected areas and become active in spring from mid April to early June. The adults lay eggs in the soil around the bases of cucurbit plants. The eggs hatch into larvae that feed on the roots, pupate in the soil and emerge as second-generation adults, which appear from mid July to early September. The spotted cucumber beetle does not overwinter in Illinois. Both striped and spotted cucumber beetles transmit the pathogen causing bacterial wilt disease, which requires the plants to be destroyed to reduce the spread of the disease.


Use of row covers, spraying with insecticides (recommended in your state – follow label instructions) when bees are out of the field, and observe pre-harvest intervals. Insecticides do not usually kill the insect fast enough to stop infection of the plant with bacterial wilt (See Bacterial Wilt in disease section).


cucumber beetle eating a leaf

cucumber beetles on a yellow flower

cucumber beetle close-up

cucumber beetle on a plant sprout

cucumber beetles doing massive damage to a leaf