Elm Leaf Beetle

• In May when leaves are expanding on elm trees, adults vacate overwintering sites and move to the trees. Here they feed and lay eggs.
• Each female may lay up to 800 eggs during her lifetime.
• After about a week, the eggs hatch and larvae begin feeding on leaves.
• Upon reaching maturity, larvae migrate toward the base of the tree where they will complete development to adults. This transformation requires 1-2 weeks after which time new adults emerge, return to the leaves and begin feeding and egg laying.
• By mid to late summer, the second brood of larvae will have developed into overwintering adult beetles. These move to protected locations outdoors under bark or into indoor refuges such as attics. When beetles become active in the spring they may appear in large numbers inside of homes but cause no damage.

Management

• Contact a licensed arborist to treat infested trees.
• Adult beetles may be excluded from the home by screening, caulking, and weather stripping. Beetles that gain entry may be swept or vacuumed and disposed of.

Still have a question? Contact us at Ask Extension.