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The elm leaf beetle (not to be confused with the elm bark beetle) is a pest which poses some danger to the elm tree. Adult beetles are approximately ¼ inch long. Their colour fades from yellow to olive as they mature. They have black stripes on their wing covers and four black spots on the thorax. The larvae are about 1/2 inch long and a dull yellow colour.
The adults lay eggs on the underside of elm leaves in late May and early June. After they hatch, the larvae begin feeding on the flesh of the leaf, leaving only the veins intact. About three weeks later, the adults emerge and chew small holes in the leaves.
A tree can survive an infestation of elm leaf beetles. However, its weakened state will make it more susceptible to other diseases such as Dutch elm disease.
Birds, toads, and other insects are natural enemies of the elm leaf beetle. There are also a number of effective pesticides.
To control Elm Leaf Beetles, use Borer-Miner Killer. Repeat the spray a few times, at intervals of about fourteen to eighteen days. If the trees are too tall to spray effectively, apply Once-A-Year Insecticidal Drench w/Merit.