Blister beetles occasionally cause localized areas of damage within soybean and alfalfa fields. However, the significance of damage to these crops is questionable. This is because the gregarious nature of the more commonly occurring blister beetles limits the area attacked and because soybean and alfalfa plants can compensate for substantial foliar losses. It is in this area that blister beetles may become a major concern. The bodies of blister beetles contain a substance called cantharadin. This chemical is an irritant capable of causing the formation of blisters upon those body tissues exposed to the chemical. Livestock may come into contact with blister beetles via the consumption of alfalfa hay containing dead beetles.
In the Old World two insects, called asparagus beetles, have been known as enemies of the asparagus since early times. In the year 1862 the common asparagus beetle was the occasion of considerable alarm on asparagus farms in Queens County, N.Y., where it threatened to destroy this, one of the most valuable crops grown on Long Island. Subsequent inquiry developed the fact that the species had begun its destructive work at Astoria, near New York City, in 1860, and it is now conceded that it was introduced in this locality about 1856.