(especially tomatoes) and ornamentals of their foliage.
There are several species of blister beetles which vary in
size (often between 0.5-0.75 inch long) and color (such as
black, gray or brown-striped), but most are recognized by
their elongated, narrow, cylindrical, soft bodies with
middle body part (thorax) narrower than the head or
Some home gardeners like to use hand picking as a nonchemical method for controlling these
large insects. However, wear gloves and use caution because these beetles contain a substance
called cantharidin. This chemical is an irritant capable of blistering internal and external body
tissues exposed to the chemical. On tender human skin, body fluids of adult blister beetles may
cause large, erect, watery blisters.
Chemical control of blister beetles is also possible. Cyfluthrin (Bayer Vegetable and Garden
Insect Spray) and gamma- or lambda-cyhalothrin (Spectracide Triazicide, Bonide Beetle Killer,
Bonide Caterpillar Killer) can be used for control. Cyfluthrin has a 0 day waiting period and
lambda-cyhalothrin has a 5-day waiting period on tomatoes. (Ward Upham)