South Carolina Forestry Commission
News Release

FOR IMMEDIATE RELEASE
August 21, 2007

FALL WEBWORMS:MAJOR EYESORE, BUT NOT MUCH MORE

Webworm

(Columbia, SC) --It happens every year. Your healthy trees are soaking up the last of summer’s rays. Deep inside, they’re just starting those chemical processes that lead to the beautiful fall colors we look forward to. Then we glance up to admire our favorite tree and there they are. Webworms! Ugly gray sacks of who-knows-what clinging to a branch. It’s enough to make you cancel autumn.

South Carolina Forestry Commission insect and disease specialists say it’s time to start anticipating the Fall Webworm’s (Hyphantria cunea (Drury)) return. In early July through September, masses of webbing on the branch ends of pecan, sourwood, persimmon, and other trees may start to appear. Fall Webworm caterpillars are a common pest throughout the United States. These caterpillars are known to feed on more than 80 species of trees and shrubs.

The caterpillars live in the silken mass and feed by skeletonizing the leaves (feeding on leaf tissue between the veins) which causes the leaves to turn brown, curl up, and eventually die. As the caterpillars eat the leaves inside the nest, they expand the webbing, often covering the entire branch. The caterpillars are covered in long, grey hairs. The body color ranges from pale yellow, to brown, to green with stripes on the top and sides of the body.

Fall Webworm

According to Laurie Reid, Insect and Disease scientist with the South Carolina Forestry Commission, even though the webs are displeasing to the homeowner, there is little damage done to healthy, well established trees. Reid says, “When these caterpillars are feeding, most trees have already stored enough energy for growth and survival.”

“However, if a tree has been repeatedly defoliated over several years and there is additional stress, such as drought, these factors may lead to branch death and tree decline,” Reid said.

Although control is usually not necessary, there are a few methods of non-chemical control if the homeowner finds the webs too unsightly. Where the webs are low enough, the homeowner can prune out and destroy the webs by sealing the webs in a trash bag. If pruning will affect the shape of the tree, a stick can be used to open the web. Opening the nest will allow natural predators such as birds and insects (wasps, stinkbugs, and predatory flies) to feed on the caterpillars.

At the very least what you have is an eyesore. At the very best, you have a good learning opportunity about biology to share with the children in your family!

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For more information, contact Scott Hawkins, SCFC Public Information Officer at(803) 896-8820

 

 

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