|Margined blister beetles|
Blister beetles can be quite a sight in the home garden. About this time of year, their populations build up to incredible numbers. They amass on and can defoliate plants in a day or two if the infestation is severe enough. They seem to prefer plants in the Solanaceous family like tomatoes, eggplant, and peppers.
Beetles are about a half-inch long. Their name comes from the defensive chemical, a blistering agent, that is released when they are handled or disturbed. These insects are most active in the morning and late afternoon and may disappear during the hottest part of the day. They are easily disturbed and will drop off the plant or run away if disturbed.
The striped blister beetle has a yellow-orange head and body with three long black stripes running along each wing cover. It will feed on many different vegetables but seems to prefer the fruits of solanaceous plants. They also are foliage feeders with big appetites. Striped blister beetles form large mobile feeding masses so they can descend on an area and cause a lot of damage in a short time. Other species in the area include the black blister beetle and the margined blister beetle. The latter has a black body with thin gray stripes along the wing covers and a gray abdomen. These two species frequently feed on flowers, the black blister beetle can be found on alfalfa flowers.
Pyrethroid products work well against blister beetles. Neem may be of help as a feeding deterrent. Organic controls include Neem, spinosad products, and shaking the beetles into soapy water.
Blister beetles can kill horses. For more information, http://www.ca.uky.edu/entomology/entfacts/ef102.asp