Tent caterpillar, fall webworm share similarities

By Stephanie Custozzo-Barkay

OSU Ext. master gardener volunteer intern

I noticed a large web at the end of a hickory tree – we had tent worms.

I formed my plan of attack. But my husband stopped me as I was standing, poised atop a four-wheeler with a pair of telescoping loppers in my hands.

He asked what I was doing, and I replied, “We have tent worms!” “You mean tent caterpillars,” he replied. “No, I mean tent worms.”

Well, we sounded like two children arguing about who was right. That prompted me to look up the facts to prove that I was correct.

After some research, I found that there are both tent caterpillars and tent worms.

Their real names are eastern tent caterpillar and fall webworm. They are very different in appearance, tree preference, season occurrence and where and why they make their web. They are similar by being native species, comparable damage to trees and control methods.

The eastern tent caterpillar overwinters as an egg, protected by a shiny, black lacquer-like substance. They hatch in March. The caterpillars remain together and spin a tent in a crotch of a tree. They use the tent as protection from the elements. They leave the tent early in the morning or the cool of the evening to feed on leaves.

Caterpillars are hairy and black with a white stripe. The moth is reddish-brown with two pale stripes. There is one generation per year.

According to an OSU Extension fact sheet on the fall webworm, they make their nests toward the end of branches. They usually winter as a pupa in a cocoon. Adults first appear in mid-June.

The females deposit egg masses on the undersurface of the leaves. After hatching they immediately begin to spin a web over the foliage on which they feed. As they grow, they enlarge the web to enclose more and more foliage.

The caterpillars are hairy, pale yellow with black marks. The moths vary from pure white to white with black spots. In Ohio, there are two generations per year.

Both insects can practically defoliate a tree. This is unsightly, but not lethal. The tree will generally mend and produce a new yield of leaves.

The good news is various species of natural enemies help to manage this native insect. Birds, insect predators and parasitoids control populations.

Prevention and early control are important through removal and destruction of the egg masses in winter. In the early spring, small tents can be removed and destroyed by hand. Larger tents may be pruned out and destroyed or removed by winding the nest on the end of a stick. Burning is not recommended since this can easily damage the tree.

As a last resort, there are pesticides – both organic and conventional. Be sure the specific insect is stated on the label. Always read and follow label directions for safe use of pesticides.

Visit go.osu.edu/tentcaterpillars or go.osu.edu/fallwebworm to learn more about these insects.

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