The fall webworm infestation in certain Oklahoma trees has come back with a vengeance this fall, with the second generation of pests wrapping up webs in trees. The fall webworm larva hatch from eggs deposited on tree leaves, mainly pecan, walnut, persimmon, and other fruit bearing trees.
Some ornamental trees found in the landscape such as river birch and sweet gum can also be prone to attacks. My native pecan trees were hit back in June, and now some have about 50% of the foliage either gone from the earlier attack or with new webs forming around leaves and branches.
The caterpillar forms a web around the outside of branches and feeds on leaves while inside the web. They will soon pupate in the forest floor, on bark, or in the turf and overwinter, hatching out next year as small adult moths starting the cycle all over again.
How To Deal with Webworms
We really don’t recommend treating to get rid of webworms, especially this late in the growing season. Although they are unsightly, the worms will not kill the tree. It does put some stress on trees, especially if most of the tree is covered and/or the webworms attack the same trees every year. And as is the case with all stress, combined with other factors such as drought or disease, then some trees could actually die off at some point.
If you can reach webs from the ground or with a long pole, just knock them out of the tree, or spray them with a high pressure washer. With time, our Oklahoma winds and weather will knock them down.