Blister Beetle Management in Alfalfa

Abstract

In Missouri, blister beetles are an infrequent pest of alfalfa. When present in sufficient numbers, however, the consequences can be serious. These insects cause only limited plant damage to alfalfa and soybeans. Striped blister beetle, Epicauta vittata, and other species of blister beetles, may occur in large numbers within localized areas of soybean and alfalfa fields during July and August. Rapid defoliation can occur, but the real problem with blister beetles is that they produce cantharidin, a toxin which, when ingested by horses, can cause the animals to become sick and possibly die. This publication provides some general information about blister beetles, their effect on livestock, and guidelines for reducing the number of these beetles in alfalfa.