DCNR to spray thousands of acres in Forbes State Forest to combat fall cankerworms

Renatta Signorini TribLive Fri, May 8, 2026 • 05:01 AM

The fall cankerworn is a native insect that eats leaves off of trees. (Courtesy of Mandy Smith)

The state Department of Conservation and Natural Resources is set to begin treating 5,345 acres in Forbes State Forest for fall cankerworms.

The six aerial treatment blocks are in parts of Somerset and Fayette counties.

Those areas have seen pest damage in recent years, as well as drought, which DCNR officials said makes trees more vulnerable and could hinder forest recovery.

Fall cankerworms, a native insect, feed on the foliage of broadleaf tree species, such as oaks. Eggs hatch in the spring.

The treatments will happen around the same time as targeted aerial treatments on 3,100 acres to combat spongy moths elsewhere in the state.

Officials said they hope both suppression programs can minimize forest defoliation so trees can stay healthy. The insecticides will be sprayed by two helicopters.