Grape Root Borer - Vitacea polistiformes (Harris)

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

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.

Order Lepidoptera: Family Sesiidae

Description: Brown moths with yellow bands on the abdomen. Hind wings are clear with dark brown veination. Coloration and body size mimic paper wasps. Males have four tufts of scales projecting beyond the end of the abdomen. Females are heavier than males. Larvae are white to cream colored with brown heads and are 30 to 40 mm long when mature. Hosts: Grapes Damage: Larvae feed in the roots and stem base of grapevines causing large, gouge shaped wounds. They can severely damage roots, causing loss of vigor, vine decline and, ultimately, vine death. The slow nature of vine decline may mask the problem for several years. Infestations are usually two to three years old before vine decline becomes obvious. Life Cycle: Adults emerge from the soil from late June to September. Mated females lay red -brown eggs on the soil surface and on grape leaves within eight days of emergence. Females lay about 350 eggs. Larvae enter the soil and enter grape roots. They feed on

Grape root borer larvae Photo by: Dr. HC Ellis, UGA Extension Entomologist

Grape root borer adult male and female Photo by: Dr. James Dutcher, UGA Research Entomologist.

Control: Mounding soil over the base of vines prevents larvae from entering the root zone and pupae from emerging to the soil surface. Mounding is about 60 percent effective. Hoeing the soil above the infested area of each vine in June and July will also kill and expose some pupae. A preventative barrier of residual insecticide applied to the soil surface underneath vines is the most effective control. The chemical kills newly hatched larvae as they burrow into the soil. It is best to spray just as adults are beginning to emerge but preharvest application restrictions may make it necessary to wait until immediately after harvest to spray. Adult emergence can be monitored with pheromone traps. Spray 15 square feet of soil surrounding the base of each vine. Good weed control is critical to getting good coverage.

Updated from: Horton, D. L. and H C Ellis, 1997. Weevils and Borers. In: Hudson, R. D. and D. B. Adams. 1997. A County Agent's Guide to Insects Important to Agriculture in Georgia. Entomology 97, RDH (1). Univ. of GA, Col. Ag. Env. Sci, Coop. Ext. Serv., Tifton, GA 31793.

Selected References and Suggested Readings