There are numerous varying species of blister beetle and many varieties exist within Canada. The adult blister beetle should be handled cautiously as it contains the toxin cantharadin, which results in the blistering of human skin (thus the common name). Additionally, the toxin is active when ingested; therefore, when livestock accidentally consume the blister beetle, there is the potential for digestive difficulties.
The adult blister beetle varies in colour as there are several species; which range in colour from black to magenta. The shape of the beetle is long and narrow with a wider head in comparison to the thorax. The female blister beetle will lay her eggs in the soil during late summer or early fall and they will hatch in about two weeks. The larvae feed on grasshopper eggs and then over-winter in the soil.
Optimal conditions for infestation
Blister beetles adults feed on foliage, pollen and nectar of alfalfa, canola, soybean and weed plants.
Since blister beetles are readily attracted to flowering plants, controlling the number of flowering weeds in the field and cutting alfalfa prior to bloom stage will reduce the potential for infestation.