Webworm moths making more nests in trees
Pose no threat to trees, residents

They’re hard to miss, with their large, dense white webs that seem to hang from every tree throughout the state.

Each year, Forsyth County residents experience the unsightly nests, home to the fall webworm moth, which is primarily known for the webbed nests that pop up on hardwood trees in the late summer and early fall.

While it is an annual phenomenon, this year, locals have started noticing the insect’s homes earlier and in greater abundance, though it is not exactly clear why, according to Heather Kolich, Forsyth County’s agriculture and natural resources agent.

“Though they have been more noticeable this year, it’s an annual event,” she said. “Every year, the webworm moths go for deciduous trees, where, for four to six weeks, the [caterpillars] eat the leaves at the tips of the branches, leaving next spring’s buds [alone].

“The caterpillars eat and grow and shed their skin and eat and grow and shed their skin for six instars of development and weave the web as they grow, expanding the nest, which is why we notice them more.”

Kolich said usually, the adult moths — which hatch in the spring — lay their eggs on the trees’ leaves in late summer, though they have been doing so earlier this year, which is contributing to the abundance.

In addition, she said, residents may be noticing the webs more due to the fact that the caterpillars strip the trees of their leaves as they eat.

“They don’t eat as much when they’re small, so we don’t notice them as much,” Kolich said. “As they eat more, we can see it more and I’ve even seen some trees that look like they’ve been decimated.

“They’re budding back out, though; because the caterpillars don’t eat the new buds, they’re not going to kill the trees.”

Their early abundance also doesn’t necessarily mean a colder or harsher winter, as the Old Farmer’s Almanac predicts, Kolich said.

“There’s no truth to the [prediction] of a colder winter, but it’s quite possible we have a higher population this year, which means we’ll have a higher population of their predators — birds and wasps — in the spring,” she said. “The caterpillars should be going down to the ground now, and when they leave the nests the webs will turn brown and sag and are easier to come down.”

Though not necessary for tree protection, Kolich said residents who are bothered by the nests can take them down.

“If they’re really bothered by the webs, they can take a stick and break them open or use a pressure washer, but they should be careful because a pressure washed can damage the tree,” she said. “As soon as they break them open, wasps will be there within minutes and birds will come and eat the caterpillars.

“I wouldn’t recommend spraying the nests, though. Because they’re dense and thick you cannot get any pesticides through them, and if you’re spraying overhead, the pesticides will fall back down on you, which is a bad idea.”

Doing nothing is an option, too.

“They are unpleasant looking, but they won’t cause the trees damage,” Kolich said. “Plus, they make great Halloween decorations.”