Fall Webworms
We’ve been getting a lot of calls about web-like nests in trees. These are from Fall Webworms. They are similar to tent caterpillars, however, they stay in their nest chewing the leaves as they go. We put a lot of pressure on our plants to look beautiful all the time. Then something like this seems devastating when in reality they are chewing on leaves that the trees were considering ditching soon anyway.
Fall Webworms are the larval stage of the moth. One generation per year emerges in the northern part of North America, with larvae appearing in late summer through early fall. This is why you are seeing the caterpillars now. The adult moth is mostly white in the North America regions, but in the south, it may be marked with black or brown spots on the wings. These moths have a wingspan of 35-42 millimeters. The webs are not the most aesthetically pleasing in your yard, but the caterpillars themselves are relatively harmless. Because it is almost autumn, the leaves they are eating will be gone soon anyways.
There are many predatory birds that would love a live snack such as Fall Webworm. Why not leave it and let it be? So what if it looks bad for a little bit. It’s not going to harm the tree and the insects are providing food for birds. The branches can be cut off to improve the look, however, isn’t that like cutting off your nose to spite your face? We do have an insecticidal soap that can help if you want but again it’s really not necessary.