University of Illinois Extension

University of Illinois Extension

Hort Answers

Insect Damage

Imported Cabbageworm

3 (1 = rare 5 = annual)
3 (1 = very little damage 5 = plants killed)
Cabbage, Cauliflower, Broccoli, Brussel sprouts and related crops

Plants Affected

They attack heads of cabbages, flowers of broccoli, and curds of cauliflowers making them unmarketable. Defoliation can be severe making crop unfit for sale or consumption.

Life Cycle
Imported cabbageworm adults are white or yellowish-white butterflies with black spots on the wings. They first appear in mid April and they continue to be a problem until mid September. The butterflies fly during the day and lay eggs singly on the leaves of cole crops. The eggs hatch into velvet-green larvae that feed on the upper surface of the leaf leaving the midribs intact. The bright green pupa is attached to the lower surface of the leaf by a silky thread. The pest overwinters as pupae in crop debris. The life cycle is about 5 weeks and 3-6 generations can occur in a year.


Consider using Bt insecticides, early planting and/or floating row covers in small gardens.

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