As if 2020 hasn’t been plagued enough, spotted lanternflies and cicada-killing hornets are still flying around, but the latest spooky crawlers to invade the region are arriving in droves. Fortunately, they are relatively harmless.
Residents of the Lehigh Valley are beginning to notice thick, silky, unsightly spider webs covering the branches of trees throughout the area. But while they may look like horror movies, web builders usually make a lot of noise about nothing.
It’s the stag beetle that’s causing so much chatter, not the harmful gypsy moth larvae that some feared. According to Ryan Reed, a natural resources program specialist at the Pennsylvania Department of Forestry, the good news is:
As the end of summer approaches, web worms can appear in large numbers. In fact, Reed said there was a similar epidemic in the area last year.
Unlike gypsy moth caterpillars, which are responsible for killing millions of oak and other tree species statewide, webworms build silk nests and often prefer black walnut and cherry trees, says Reed. Webworms eat leaves and never go outside their nests to eat, so the danger posed to trees is almost purely aesthetic.
Reed said last year’s outbreak did not have a significant impact on forest health.
“The damage caused by these caterpillars is minimal, as it usually occurs near the end of the growing season when trees build strong root food stores.”
Lehigh Valley residents worried about webworms should probably leave their nests alone, experts say, and not risk their nests being destroyed by disaster. According to Michigan State University’s Extension, the Master Gardener Hotline has received many calls from tree owners trying to get rid of pests with dangerous methods like fire and pesticides.
Humans will end up doing far more damage to trees than webworms, according to the MSU website. I have parasites. Most importantly, webworms do not touch the next year’s leaf buds and feed on leaves that are nearing the end of their photosynthetic career.
Fall webworms feed on almost 90 species of deciduous trees in Pennsylvania, according to the Penn State Extension. Not only are they often mistaken for gypsy moth larvae (which don’t build nests), they behave similarly to eastern ladybirds. , partially eaten leaves, and faeces are distinguishable.
If you’re looking for someone responsible for this year’s web worm outbreak, point your finger at Mother Nature. Webworm populations are typically depleted in severe cold, but experts say they are enhanced by mild winters and other factors.
“Populations are largely governed by predator/prey dynamics and weather,” Reed said. “I suspect that warmer winters have increased the generation of insects with multiple generations per season. It’s an alarming fact that Pennsylvanians should resonate with. Over the past 50 years, North America has lost more than 3 billion birds (almost 30%).
“Having said that, most native insect populations follow a typical ‘boom and bust’ cycle, and we can expect this population to normalize again in the coming years. ”
What You Need to Know About Autumn Web Worms
According to the Penn State Extension, webworms usually begin to emerge in late August, and young larvae are pale yellow or greenish with black spots along their bodies. When fully grown, they are covered with whitish hairs derived from black and orange warts.
It takes about 6 weeks for the larvae to mature. Eventually they leave the web and pupate on or in the soil.
Depending on Pennsylvania’s geographic location, one or two generations may occur each year.
Pesticides should not be used on local autumn webworms that may contaminate feed, streams, or ponds.