Washington has numerous beetles belonging to several families like scarab, and longhorn beetles, distributed in the eastern and western parts. Eastern Washington houses species like the mountain pine beetle, a significant threat to the forests, alongcol3 Northern Carrion beetle, American oil beetle, etc.
The ten-lined June beetle measuring up to 28 mm found between June and July mainly occurs in the southeastern parts of the state. The big-sized Japanese beetle is not a native here but can be found in some parts infesting plants. Another annoying pest here is the blister beetles found in alfalfa plants, which are harmful to horses.
Beetles in Washington (WA)
Largest Beetles: Ten-lined June Beetle, Japanese Beetle, California Prionus Beetle