Webworm Worries

How ‘bout those webworms? Seasonal changes are typically subtle, except for the perceived blight of these larvae defoliators. How lasting is their impact?

by Peter Gordon, Elachee’s Director of Education

Although unsightly, webworms do not cause long-term harm to their host tree.Many of the indicator signs that northeast Georgia has begun its slow and gradual transition from summer to fall escape our notice. Bird songs, so symphonic during spring nesting season, have largely disappeared from our auditory landscape. Nuts are appearing on hickory and oak trees; berry producers like dogwood, black gum and sourwood have set fruit. Blackbirds are flocking and the sun sets a little earlier each night. Isn’t nature subtle?

And then there are the fall webworms (Hyphantria cunea)!

These little defoliators are as subtle as mud on a white rug, a missing tooth from a perfect smile or an open bag of mixed garbage dropped on a residential drive. They seem to be more prevalent this year, but this same claim goes back several years in adjoining states and regions. 

Webworms are the larvae of the Fall Webworm Moth which is found in most of the lower 48 states. It lays 40-100 minute, marble-shaped eggs on the outer limbs and leaves of trees and shrubs. Favorite targets appear to be black cherry, sourwood, redbud, hickory, dogwood and other tree species. 

Upon hatching, the tiny caterpillars, the larvae of the Fall Webworm Moth, construct a protective web that shield them from birds and other predators.

Upon hatching, the tiny caterpillars construct a protective web that shield them from birds and other predators. Then they begin to eat, grow and go through as many as 11 different stages of development, or instars, before becoming an adult.

Tent caterpillars (Malacosoma disstria) choose similar tree species to inhabit, but do so in spring and always lay their eggs in the crotches of trees.

Fear not. The good news is the webworm’s gluttonous impact is cosmetic and has no long-term impact on the host tree. The caterpillars are also an important source of food to a large variety of birds, spiders and wasps.

The bad news is the unsightly webs will linger well into the fall. It may take weeks for the caterpillars to complete their full development cycle into adulthood. 

And, for good or bad, this insect does give us something to talk about. They are fodder for nature-inspired conversation as webworms really have no competing peer to discuss as we move into the autumn season.  

What’s in Your Yard?

We have found so many interesting creatures and witnessed many rare sightings this summer, we want to know if you have, too. Share your stories and photos. Send us an email.

Have you read other Elachee Nature Mixed In blog posts this summer? If not, check out the blog.