Friday, August 19, 2016

Fall Webworms Spinning Their Webs

by Karla Salp
Pest Program Outreach Coordinator

If you’re seeing web “nests” or “tents” in trees and lots of little caterpillars nearby, you have probably spotted a gypsy moth imposter.
Fall webworms in lilac tree

We have been receiving many reports recently of gypsy moths from concerned citizens who have spotted some of these webs. We definitely want to know about gypsy moths, but luckily what you are seeing right now are just fall webworms.
Close up of fall webworm nest. Black spots are frass (poop.)

Fall webworms hatch out of eggs in mid to late summer and begin spinning protective webs in trees. The webs protect them from predators, such as birds, so they can eat the leaves of the tree where they find themselves in relative peace.

While the web-covered branch or branches may be unsightly, the fall webworm infestations are usually nothing to be too worried about. Unlike gypsy moths, which can decimate entire forests, fall webworm infestations are usually limited to a branch or two within a tree.
Burning infested branches

You don’t have to take any action, but if you want to, controlling the pest is relatively easy. You can simply prune out the infested branch and burn it. Remove it as soon as the fall webworms are detected as the caterpillars will continue to grow and expand their nest, eating more of your tree along the way.

Learn more about the gypsy moth and common imposters on WSDA’s website.

Note: Before burning branches, be sure that there isn't a burn ban in effect in your area.