Within a month of finding suitable food, the larvae go through three more, increasingly sedentary, stages. They remain in this stage for the next seven months. Importance to Crops Blister beetles occasionally cause localized areas of foliage damage as they feed within soybean and alfalfa fields. However, the threat of inflicting economic damage through leaf feeding alone is questionable. Soybean and alfalfa plants compensate for substantial foliar losses so that little to no yield loss results from blister beetle feeding.
Beetles feed and then move about or leave the field.
Importance to Livestock Blister beetles contain a substance called cantharidin. This chemical is an irritant capable of blistering internal and external body tissues exposed to the chemical. Livestock most frequently come into contact with blister beetles as they consume alfalfa hay containing dead beetles. Blister beetles can be crushed and killed as alfalfa is swathed. Cantharidin may contaminate hay without the beetle bodies being evident if the beetles are squashed during haymaking.