Fall webworms

County Agent’s Corner



Even though fall may feel like an eternity away, keep a lookout for a traditionally late summer/early autumn pest a little sooner than expected this year. I am referring to the fall webworm caterpillar, Hyphantria cunea.

Fall webworms construct webs at the end of branches, encapsulating all of the leaves. These leaves serve as their food source with the web expanding as the caterpillars feed.

One point to mention – they are not picky eaters. Fall webworms have a wide host range, feeding on more than 100 deciduous trees and shrubs in our region.

As ominous as it may seem, the bark of the fall webworm is worse than its bite. This pest only feeds on the current year’s growth, leaving leaf buds for next year intact.

Additionally, there are more than 50 predators and 36 parasites that consider the fall webworm their meal of choice. Therefore, large numbers are usually never a problem.

Historically, gardeners have taken unnecessary extreme measures to control this pest. Branches have been burned or removed. Pesticides have been applied overhead, resulting in getting more pesticide on the gardener than the pest. In fact, these actions do much more damage to the tree than the fall webworms.

If a large tree is plagued with these pests, there is really no need to worry at all. The fall webworms are basically just a nuisance. However, if a smaller tree is engulfed, breaking up and removing the web is helpful.

Take a stick or garden tool handle and push a hole in the sticky webbing and then pull. Submerge the webby mass in a bucket of soapy water for a day or so. Any remaining webworms left in the tree will be fair game for the predators mentioned above.

So, if you see these pesky (but harmless) creatures in your tree, look on the bright side. That just means that summer is winding down and fall is on its way.

Good luck and happy gardening!

This column includes research-based information from land-grant universities around the country, including Alabama A&M and Auburn Universities. Email questions to O’Rear at Bethany@aces.edu or call 205-612-9524. Like us on Facebook. Follow us on Twitter. The Alabama Cooperative Extension System (Alabama A&M University and Auburn University), is an equal opportunity educator and employer.