The Elm Leaf Beetle (not to be confused with the Elm Bark Beetle) is a serious pest of Elm trees throughout Colorado. The insects feed on Elm leaf flesh causing death and the appearance of brown . Repeated injuries can weaken a tree through stress, making it more susceptible to even more serious conditions including Dutch Elm Disease.
Adult beetles overwinter in protected locations, emerging in the spring to mate and lay eggs. In the spring, females lay a yellow egg mass on the underside of leaves. Larvae (grubs) can hatch multiple times throughout the warmer months. The larvae hatch and eat the underside of the Elm leaves, causing browning and premature dropping. Later in the season, the larvae pupate and emerge as adults to overwinter and begin the cycle again. The beetles can become a nuisance in the house, as they attempt to find a suitable place to spend the winter.
The Elm Leaf Beetle adult is approximately ¼ inch long with color fading from yellow to green as an indication of age. They have black stripes on their wing covers and four black spots on the thorax. The larvae are about ½ inch long and have a dull-yellow appearance.
Insecticide application and trunk banding are commonly used methods for dealing with the Elm Leaf Beetle. Walker Tree Care has as a plant healthcare department trained to deal with all instances of Elm Leaf Beetle.