Western Corn Rootworm

Western Corn Rootworm Life StagesWestern Corn Rootworm Life Stages
Western Corn Rootworm and Feeding Damage on CornWestern Corn Rootworm and Feeding Damage on Corn
Feeding Damage on Corn SilkFeeding Damage on Corn Silk
Corn Root Damage from Larval FeedingCorn Root Damage from Larval Feeding

HOSTS

  • Corn

DESCRIPTION

Adults are small beetles with yellow-green bodies and three black stripes on the forewings. Larvae are creamy white with a brown head capsule.

BIOLOGY

Egg | Larva | Pupa | Adult

Western corn rootworms are active early June to mid-July. There is one generation per year. They overwinter as eggs in the soil. Monitor adults with yellow sticky traps; check and replace traps weekly. 

SYMPTOMS

Larvae feed with chewing mouthparts on roots causing browning, lesions, tunneling, curved cornstalks (goosenecking), yield losses, and susceptibility to root and stalk diseases. Adults feed with chewing mouthparts, resulting in poorly-filled ears.

GENERAL MANAGEMENT

Larval feeding is the most damaging, while adult feeding will not typically result in economic loss.

  • Rotate corn crops
  • Plant early
  • Select varieties with vigorous root systems that are well adapted to the area

INSECTICIDES

Consider treatment if adults exceed 35 per trap per week in continuous corn (fields where corn is planted for two or more consecutive years).

























Precautionary Statement: Utah State University and its employees are not responsible for the use, misuse, or damage caused by application or misapplication of products or information mentioned in this document. All pesticides are labeled with ingredients, instructions, and risks, and not all are registered for edible crops. “Restricted use” pesticides may only be applied by a licensed applicator. The pesticide applicator is legally responsible for proper use. USU makes no endorsement of the products listed in this publication.