Webworms feeding in a tree near you this fall

Don’t let their name confuse you. In parts of the state, fall webworms have already made their presence known this year.

While driving through north Georgia last month, I couldn’t believe the number of webs I saw.

In Middle Georgia, the nests are just now becoming more noticeable as they grow along with their caterpillars inside. The webs, found at the tips of branches on a variety of hardwood trees, are easy to spot.

Not to be confused with the Eastern tent caterpillar, which shows up in the early spring, the fall webworm is prevalent in late summer through the fall. The Eastern tent caterpillar makes webs near the crotches of the branches (where they join), while fall webworms make theirs at the ends of the branches.

Fall webworms are more visible because of their web placement and because they remain in place even after the webworms are gone.

Fall webworms, one of our native insects, can be up to one inch long and come in two color forms.

The worms with black heads are yellowish white, while those with red heads are brown. Both forms are covered with long, soft gray hairs.

While the webworms feed on many different species of trees, their favorites tend to be pecan, black walnut, mulberry, elm, sweet gum, willow, apple, ash and oak. It is hard to pass a pecan orchard this time of year without spotting at least one or two webs.

The caterpillars form fine silken webs at branch tips, enlarging the webs if they need more leaves to feed on. They feed for a couple of weeks before they become pupae.

These pupae eventually turn into white moths, which can fly away to lay more eggs for subsequent generations of webworms. There can be up to four generations of fall webworms in a year. They survive the winter as pupae in cocoons in protected places.

While the caterpillars feeding on tree leaves may cause minor damage, the tree should recover. Healthy trees are able to withstand a great deal of insect damage to their leaves without lasting injury. They can lose almost all their leaves and still live.

This is true of most deciduous trees (trees that lose their leaves in the fall). If the trees are in some otherwise weakened state, the caterpillar feeding could be more problematic.

Since most trees will not die from caterpillar attack, spraying is not typically recommended. Chemical control is not easy because of the location of the web and the dense webbing.

If the webworms can be tolerated for a while, they will eventually leave.

In a homeowner situation, pesticides should be applied when the webs and caterpillars are still small. Consider products such as insecticidal soap, horticultural oils or Bt (Bacillus thuringiensis) to kill small caterpillars.

A second control tactic is to prune off and dispose of the nest. The easiest control option is to pull down and disrupt the webs with a pole or stick. This exposes caterpillars to bird and wasp predation. For information, visit: http://www.bugwood.org/factsheets/webworm.html

Upcoming Events

Fall Forages Program: Aug. 30 from 6-9 p.m. at the Putnam County Extension Office. Topics include establishment and maintenance of cool season forages, including weed control. The cost is $5, which includes dinner. Call 478-986-3958 or 706-485-4151 for details.

Master Gardeners of Central Georgia Fall Garden Plant Sale: Sept. 22 from noon to 5 p.m; Sept. 23 from 8 a.m. to 5 p.m.; and Sept. 24 from 8 a.m. to 3 p.m., at the State Farmers Market, 2055 Eisenhower Parkway. Master Gardeners will also be available to answer gardening questions. This year’s event will also include garden art and educational booths. Admission and parking are free. For more information, email askamg@mgcg.org or call 478-751-6338.

This story was originally published August 24, 2016 at 9:00 PM with the headline "Webworms feeding in a tree near you this fall."