Western Sycamore Borer-This borer is a moth that resembles a yellow jacket wasp. Adults are yellow with black marks. Larvae mines on oaks and sycamores bark, creating several tunnels under the surface. Larvae rarely damage the cambium or feed into the wood of the tree. Brown and reddish sawdust that resembles coffee grounds is found outside the tunnels or on the ground below infested areas of the tree. This reddish brown frass is a sign of new attack on the tree. Larvea normally pupaes under the bark and only one generation occurs per year. Adults merge from May through August. Old trees and injured tissues are the favorite spots for laying eggs and feeding. The damage from Western Sycamore Borer is considered to be of minor importance to the overall health of the tree, but creates an advious cometic damage on the bark. Depending on the severity of the damage, insecticides can be applied in May through August but multiple application may be needed.
Damage to Bark