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Brown elm leaves a sign of beetles’ destruction

Homeowners in Middle and Morth Georgia are urged to report damage from elm leaf beetles

 

Elm trees across middle and northern Georgia may see their leaves turning brown and lacy earlier this year, not because of the fall weather, but because of an infestation of beetles.

Map of counties affected by elm leaf beetlesElm leaf beetles, a species native to Europe, either leave a pattern of holes across leaves or strip the tissue off of leaves leaving a skeleton of veins, causing them to prematurely turn brown. This year elm leaf beetles have been reported in a swath of counties from Macon to Elberton. While the trees don’t typically die from the damage, a tree’s health can suffer if the leaves are eaten by the insects for several years in a row.

“Defoliation is expected to continue into the fall, so this is likely to be an issue for Extension agents for numerous weeks,” said Elizabeth McCarty, forest health specialist with the University of Georgia Warnell School of Forestry and Natural Resources.

McCarty said the Georgia Forestry Commission and UGA Extension agents have been receiving many reports of damage, and the commission is now collecting data on beetle damage from the affected counties. If a property owner sees an elm tree with prematurely brown leaves—often with a pattern called “skeletonized,” which leaves the larger veins intact—McCarty recommends they contact their local Extension agent or the Georgia Forestry Commission.

It’s also important, she added, that homeowners don’t spray an entire tree to kill the beetles.

“Systemic insecticides can be applied earlier in the year if an infestation is expected,” she said. “But, at this point, they will not be very effective.”

Tree with leaves affected by elm leaf beetlesIn late summer and early fall, the beetles begin to move to protected sites, such as woodpiles or mulch, where they stay during the winter. They typically move back to the trees in the spring once elm trees’ leaves emerge, lay their eggs while feasting on the new leaves, and then the beetles’ larvae crawl back down the tree to prepare for a second generation in the same year.

Adult beetles produced toward the end of the summer continue to eat the leaves but do not lay another round of eggs. Instead, they move to sheltered areas for the winter, and the cycle continues. Often elm trees are also affected by the larger elm leaf beetle, which only has one generation per year.

The Colorado State University Extension reports that the best method of controlling elm leaf beetles is naturally, through long, cold winters or a late spring freeze. But another method that’s likely easier for homeowners to control involves applying an insecticide, such as imidacloprid, into the soil around the tree. Other control methods involve applying an insecticide to the trunk of the tree, aiming to stop the larvae as it crawls down in early summer.

For more details or to report beetle damage, visit the Georgia Forestry Commission's website.

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