BLISTER BEETLES (Spanish Fly)

Beetles of the Coleoptera Family Meloidae are

Predators of bee and grasshopper egg masses as

larvae. Most are active, colorful beetles, of green,

blue back, spotted, or grey. They feed on flowers,

and sometimes leaves, of many plant species. Blister

beetles are called blister beetles because their fluids

contain the chemical Cantharidin which is very toxic

to mammals, especially horses. Horses in SER Washington

are sometimes poisoned by dead blister beetles in

alfalfa hay. It is very important for horse owners

to buy blister beetle free hay and for alfalfa growers to

avoid late cutting of blooming hay and keep their

fields clean of blisters beetles.

The genus Lytta (Lytta nutalli and L. versicatoria) are

large green blister beetles found in the PNW and Canada.

Lytta versicatoria L. is a cosmopolitan species originally

from Europe which is the commercial source of Cantharidin

known as the Spanish fly. L. nutalli is known from Canola in

Canada.

Blister beetles are pests of home garden flowers, often

damaging Iris and other showy flowers in the late spring.

Since they are large chewing beetles, home garden

pesticides are effective when needed. Read and follow labels.