Salem-News.com Western Tent Caterpillars articles

Parts of Oregon Inundated by Western Tent Caterpillars

Western tent caterpillars produce one generation per year.

(SCAPPOOSE, Ore. ) - Oregon State University Extension offices in Columbia County are being inundated with calls by concerned members of the public about localized, often severe, defoliation of hardwoods in the northern portion of the county.

The defoliation has been most noticeable on red alders, cottonwoods, willows and fruit trees; however, other broadleaf trees and shrubs are also being affected. The damage is caused by an outbreak of western tent caterpillars (Malacosoma californicum), a moth native to the Pacific Northwest.