Three Things You Need To Know About Elm Leaf Beetles

Elm leaf beetles are an invasive pest that can destroy your backyard elm trees. Here are three things you need to know about elm leaf beetles.

What do elm leaf beetles look like?

Elm leaf beetles are large—about 13 millimeters long—and have yellow or olive bodies with dark bands, so they'll stand out against the bark of your elm trees. The larvae are also quite distinctive; they have yellow bodies and a black stripe.

How do elm leaf beetles affect trees?

Female elm leaf beetles lay their eggs on the leaves of your prized elm trees. A single female beetle can lay 800 eggs in her lifetime, so it doesn't take many female beetles to infest your trees. When the eggs hatch, the larvae feed on the elm leaves, as do the adults.

When elm leaf beetles feed on your trees, you'll notice that the leaves are turning brown and that the leaves are dropping earlier in the season than they should. This doesn't just make your trees look unattractive; it also puts them at risk of problems like limb dieback. After two or three years of severe defoliation, affected elm trees can even die and need to be removed by a tree removal company.

How can you get rid of elm leaf beetles?

To get rid of elm leaf beetles, you'll need to break their life cycle. This can be done by treating the affected trees with insecticides. Elm leaf beetles are susceptible to a variety of insecticide products, including insecticidal soap and permethrin, that are available at garden centers.

To time the application properly, start monitoring your trees in May for the appearance of adult beetles. Wait for the beetles to lay their eggs, and as soon as they hatch, spray the trees. Use a hand-pump garden sprayer to apply the insecticide, and try to coat both the trunk and the foliage. If your tree is large, or if you're not comfortable working with insecticides, hire an arborist to help you.

Insecticides can kill good types of bugs, like bees, so you may want to try to control the elm leaf beetles with bands. Bands are sticky traps that extend around the diameter of the trees' trunks and capture any crawling insects that try to climb the trunk. For best results, bands should remain in place until mid- to late-May. The bands need to stay sticky to be effective, so you'll need to reapply the sticky substance as needed.

If you need help saving your elm trees from elm leaf beetles, hire a tree service like Coryell Tree Service.