You’ve seen them.
Tree branches, covered in webs. And unless they’re very small, entire trees are not covered, it’s just a limb or two are coated with the creepy webbing.
But what is causing the specifically placed webs? And should you be scared of what’s inside of them?
Unless you are a tree being infested by the fall webworms, you’re safe from what a North Carolina State professor in entomology, Dr. Steven Frank, calls “a perennial nuisance and in some cases a destructive pest.”
The webs are cocoons spun by fall webworms, where the females lay their eggs on “undersurface of the leaves,” and feed off the branch the web covers, according to the Penn State College of Agricultural Sciences research.
In spite of the shocking image of a tree branch being smothered in a web, fall webworms pose no threat to people or most trees.
The webs are “a big, showy bag ... over the end of a branch on a shade, fruit or ornamental tree,” according to Michigan State University, which said fall webworms can be lumped into a group of insects that it calls “much ado about nothing.”
HGTV called the damage caused by webs “strictly cosmetic.”
A Clemson University publication echoed that sentiment, saying “true damage to the tree is minimal,” as the fall webworms’ eggs will hatch in about a week, and proceed to feed off the living leaves for about six weeks before departing the tree.
“Fall webworms upset people because they are ugly not because they damage trees that much,” Frank wrote.
The prime season for fall webworms is late summer through early fall, according to Penn State. That is one of the ways to differentiate fall webworms from similar insects — Eastern Tent Caterpillar and Gypsy Moths.
Fall webworms and tent caterpillars are less destructive to the trees they infest than Gypsy Moths, according to the Washington State Department of Agriculture.
And in spite of many similarities, there are subtle differences between fall webworms and tent caterpillars.
Tent caterpillars spin their webs in the spring, compared to summer for fall webworms; and tent caterpillars’ webs are found in “in crotches of branches,” as opposed to the end of the branches where fall webworms cocoons are located, Clemson University reported. Additionally, fall webworms can produce four generations a year, so their webs will be active longer, opposed to tent caterpillars single generations.
Perhaps the biggest threat posed by fall webworms is the overreactions people have in attempts to remove the webs.
Michigan State reported that fires have been set in attempts to get rid of the webs, and pesticides are more likely to harm the person spraying them since the webbing is so strong it will repel the spray.
Tearing the web down with a pole, or puncturing it to allow natural predators access to the fall webworms is the best approach to getting rid of the webs, HGTV reported.
On their own, the webs will likely dissipate by the winter, according to Penn State.
By that point, some other white, clingy substance could be coating a tree, with snow creating a much greater nuisance.