Blister Beetle

Blister Beetle Larvae and AdultBlister Beetle Larvae and Adult

Blister Beetles of UtahBlister Beetles of Utah

Striped Blister Beetles and Feeding DamageStriped Blister Beetles and Feeding Damage

Alfalfa Fields can Attract Blister BeetlesAlfalfa Fields can Attract Blister Beetles

HOSTS

  • Alfalfa
  • Legumes
  • Solanaceae
  • Potatoes

OVERVIEW

Blister beetles in the genera Epicuata are found throughout North America and can be found in a variety of different colors and patterns. Multiple species have been known to feed on vegetable crops, yet few usually cause destructive feeding damage.  

Blister beetle populations are of economic concern when found in forages, such as alfalfa, intended for livestock feeding. Blister beetles produce cantharidin, a natural toxin that can cause painful blistering and swelling in animals and humans. If blister beetles or cantharidin is consumed by livestock, especially horses, it can be potentially lethal.

DESCRIPTION

Adult Epicuata species are elongated and slender. The “neck-like” thorax is narrower than the abdomen and head. Larva are cream-colored with brown heads. The first instar is mobile with long legs, but later stages have reduced legs and move little.

BIOLOGY

Egg | Larva | Pupa | Adult 

Blister beetles lay clusters of 100-200 eggs in the soil. After hatching, larvae actively search for grasshopper or bee egg cases to feed on to complete their juvenile life stages. They will overwinter as larvae in the soil and pupate in the spring. Adults emerge from the soil during the growing season to feed on plant flowers and foliage. For many species, a single generation occurs per year. 

SYMPTOMS

Adults feed on plant foliage and blossoms. They can often be found aggregating in feeding groups, especially during periods of bloom. Large groups of blister beetles can cause severe defoliation to crops.  

Both live and dead blister beetles contain cantharidin. Beetles can be incorporated into hay bales when the hay is harvested. Crushing or crimping hay containing blister beetles can further incorporate their bodies into the forage

SCOUTING

  • Feeding damage can be concentrated in areas where the beetles are congregating and on field edges. 

GENERAL MANAGEMENT

  • Blister beetle populations are influenced by grasshopper populations, as they serve as a food source for larvae. Reducing grasshopper populations indirectly suppresses blister beetle populations.
  • Row covers can physically exclude blister beetle adults from crops.
  • Blooming alfalfa attracts blister beetles. Cutting the hay before peak bloom can reduce the chance of blister beetles in the alfalfa. 

INSECTICIDES

Coming Soon

Precautionary Statement: Utah State University and its employees are not responsible for the use, misuse, or damage caused by application or misapplication of products or information mentioned in this document. All pesticides are labeled with ingredients, instructions, and risks, and not all are registered for edible crops. “Restricted use” pesticides may only be applied by a licensed applicator. The pesticide applicator is legally responsible for proper use. USU makes no endorsement of the products listed in this publication.