Charleston, W.Va. (AP) -- Agriculture Commissioner Gus Douglass says about 40,000 acres of woodlands in West Virginia have been treated this year to fend off hungry gypsy moths.

Douglass said Wednesday the annual spraying program helps to protect forests from the insects. He says the gypsy moth is "the most serious plant pest in West Virginia."

Douglass says gypsy moth caterpillars feed on more than 500 species of trees and shrubs, weakening or killing the plants.

At least 81,000 acres of forest were defoliated by the insects last year.

(Copyright 2009 by The Associated Press. All rights reserved.)