Sweetpotato Weevil - Cylas formicarius elegantulus (Summers)

Dr. D. L. Horton, Professor and Extension Entomologist, The University of Georgia, Department of Entomology, Athens, GA 30602,
Dr. H C Ellis, Professor and Extension Entomologist, The University of Georgia, Department of Entomology, Tifton, GA 31793

Order Coleoptera: Family Curculionidae

Description: Adults are ant-like, shiny, blue-black, snout beetles whose "waist" and legs are bright orange-red. They are about 6 mm long. Larvae are legless, white to cream colored with a pale brown head. Larvae are about 9 mm long. Hosts: Sweet potato, morning glory, and other plants of the same family. Damage: Larvae cause damage by burrowing through the stem and roots. Even slightly infested sweet potatoes are unfit for food. Heavily infested tubers are unfit even for stock feed.

Sweet potato weevil adult and larvae Photo by: HC Ellis, UGA

Life Cycle: Breeding is continuous throughout the winter, especially in potatoes in storage. Eggs are laid singly in small cavities eaten out in the stem or tuber. Eggs hatch in less than a week and larvae feed inside for two to three weeks. Pupation occurs in the potatoes. The pupal stage lasts about a week to 10 days. There can be as many as eight generations per year.

Control: Sweet potatoes should not be planted in infested areas until permission and instructions have been obtained from the Division of Entomology and Pesticides, Georgia Department of Agriculture, 19 Martin Luther King Drive, SW, Atlanta, Georgia 30344.

In: Roberts, P. M. and G. K. Douce, Coordinators. 1999. Weevils and Borers. 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