University of Illinois Extension

University of Illinois Extension

Hort Answers

Insect Damage

Western Corn Rootworm

4 (1 = rare 5 = annual)
4 (1 = very little damage 5 = plants killed)
Corn and cucurbits

Plants Affected

The Western corn rootworm adults feed on corn silk and pollen in cucurbits thus reducing or destroying the crop yeild.

Life Cycle
They have yellow abdomen, and the wings do not cover posterior part of the abdomen. This distinguishes them from striped cucumber beetles. They appear in late July and early August.


European Corn Borer sprays can control adult western corn rootworms as well. The reduction in adult population is important for reducing the number of eggs laid which will hatch into larvae and start feeding on corn roots the following year.

Monitoring the moths, and spraying with insecticides (recommended in your state) but observe the pre-harvest interval.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic