Mexican Bean Beetle - Epilachna varivestis Mulsant

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 Coleoptera: Famly Coccinellidae

Description: Adults are oval in shape and orange to copper-colored with eight black spots on each wing cover. They resemble lady beetles and ar one of three coccinellid species which are plant feeders. Adults are about 6 to 8.5 mm in length. Larvae reach a maximum length of 9 mm; are yellow, soft, and grublike; and are covered with six rows of dark, branched spines. Hosts: Soybean and other legumes, including many varieties of beans, alfalfa, clover, cowpeas, beggarweed, and kudzu.

Mexican bean beetle adult Photo by: Philip Roberts, UGA

Damage: On soybeans larvae and adults cause injury by feeding on the surface of leaf tissues. The tissue that remains gives the leaf a lacy appearance. Damaged tissue will die and turn brown.

Life Cycle: Adults overwinter in plant debris and other protected places and emerge when surrounding temperatures reach 50 degrees. Because temperatures will vary by overwintering location, emergence occurs for several weeks. Adults live for about six weeks, and females lay several hundred yellow-orange, elliptical eggs in groups of 40 to 60 on the undersides of leaves. Eggs hatch in about a week (depending on temperature), and larvae feed 2 to 4 weeks. Last instar larvae attach their abdominal end to a leaf and pupate. The pupation period last 5 to 10 days. There are 3 to 4 generations each year.

Control: Treat based on defoliation thresholds. Soybean treatment thresholds:

Prior to full bloom: defoliation reaches 30 percent.

Full bloom until mid pod-fill: defoliation reaches 15 percent.

After full pod-fill: defoliation reaches 25 percent.

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