Dr. Phillip Roberts, Extension Entomologist, The University of Georgia, Department of Entomology, Tifton, GA 31793
Dr. Paul Guillebeau, Extension Entomologist, The University of Georgia, Department of Entomology, Athens, GA 30602

Order Lepidoptera: Family Crambidae

Description: Adult: Wingspan around ½ inch. Brown-yellow forewings mottled with darker brown; hind wings pale gray. Short erratic flights when disturbed Larvae: First instar less than 1/8 inch, yellow-gray with a wide, dark head. Larger larvae yellow-gray with five dark longitudinal stripes. Black head has 'V' shaped mark. Larvae reach 1/2 to 3/4 inch. Hosts: Most crucifers and related weeds, including cabbage, turnip, beet, collard, cauliflower, kale, rutabaga, radish, kohlrabi, mustard, rape, horseradish, shepherds purse, and purslane.

Webworm Photo by: Philip Roberts, UGA

Damage: Typically damage only late summer or fall crops. Larvae bore into buds, stems, and stalks, which disfigures or kills plants. Feeding on outer leaves is not usually economically important. Feed during the day under silken webs.

Life Cycle: Life cycle information is incomplete. Related species overwinter in soil as pupae or larvae in silk-lined cells. Moths lay up to 350 eggs on host plant buds. Eggs hatch in 3 days. Larvae feed in buds, later moving to outer leaves and spinning webs. Pupate in leaf debris.

Control: Typically unnecessary on spring crops. Usually a minor pest in the late-summer and fall. When pesticides are necessary, organophosphates, carbamates, pyrethroids, and Bacillus thuringiensis are used.

In: Roberts, P. M. and G. K. Douce, Coordinators. 1999. Foliage Feeding Insects. A County Agent's Guide to Insects Important to Agriculture in Georgia. Univ. of GA, Col. Ag. Env. Sci., Coop. Ext. Serv., Tifton, GA USA. Winter School Top Fifty Agricultural Insect Pests and Their Damage Sessions, Rock Eagle 4-H Ctr., Jan. 20, 1999.

Selected References and Suggested Readings