bean beetle, common name for a destructive beetle, Epilachna varivestis, of the ladybird beetle family. Although nearly all other members of this family are beneficial carnivores, the bean beetle attacks leguminous plants, especially beans. Both larva and adult feed on the undersides of leaves and sometimes on the pods. The adult is yellow, with black spots; the yellow, oval-bodied larva has forked spines. Bean beetles overwinter as adults and in early spring lay masses of 10 to 50 eggs on the undersides of leaves. One to four generations occur annually, each requiring about a month to mature. Since most damage occurs during July and August, early-maturing beans suffer the least damage. Removing old bean plants helps to destroy overwintering beetles, although many escape to nearby sheltered areas. Chemical insecticides are used for control. Before 1920 the bean beetle, also called Mexican bean beetle, was found only in the SW United States, but it now occurs throughout most of the United States, except on the Pacific coast. It is classified in the phylum Arthropoda, class Insecta, order Coleoptera, family Coccinellidae.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.