The Elm Leaf Beetle—The First Step to Elm Tree Loss

The elm leaf beetle is a dangerous pest of the elm tree. Native to Europe, it was unintentionally brought to North America. Both the adults and larvae feed on the emergent leaves of the elm.

This insect usually does not kill the tree, but weakens it to the point that diseases can step in and finish the tree off.

The adult and larvae do most of the damage, but all development stages do damage to elms.

The larvae leave the upper surface and veins of the leaf undamaged, but cause them to shrivel up and fall.

The immature beetles create small, rough but distinct holes in the leaves, and are in general less damaging than their young.

The elm leaf beetle spends the winter in dry, protected spots.

The Elm Leaf Beetle Life Cycle

The following photos show the various stages of the Elm Leaf Beetle and the damage done to elm trees.

The mature beetles are generally 1/4" (6 mm) long, yellowish-green with a somewhat black stripe surrounding the top. They also have yellowish legs and feelers.

Early in the year they journey to elms and feast. At the end of May and early June, females lay eggs in tiny, yellow-colored groups of approximately twenty each, attaching them to the bottom of foliage. Most of these eggs hatch out within one week.

Larvae develop to around 1/2" (1.25 cm) long. They're yellowish in color. Larvae depart from the undersides of the leaf after 3 to 4 weeks.

Eggs Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org	Larva Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org
Pupae Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org	Adult Photo courtesy of Gyorgy Csoka, Hungary Forest Research Institute Bugwood.org
Damage Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org

Controlling the Elm Leaf Beetle

These bugs are hard to control. However, using neem oil, Bacillus thuringiensis and soap spray on the foliage is effective.

If this page was valuable for you, please share your new knowledge. Click Like...