Tom Turpin
Professor of
Purdue University







Tenting On The Old Campground

For many folks, spring means the return of the camping season. It's time to retrieve the musty-smelling tent from the basement or attic. But before most human campers make their first spring foray into the great out-of-doors, the insect tents are already in place.

The most conspicuous of the insect tentmakers is the eastern tent caterpillar. This insect, a hairy brown caterpillar that grows to about 2 inches in length, has been observed making tents in America's trees since 1646.

The insect passes the winter in the egg stage. In early spring, the eggs hatch. Young larvae band together and produce a large thick web, called a tent. The tent is normally located in the fork of a tree.

Larvae do not feed within the tent. They use the tent for protection from the weather, and possibly, from predators. Hungry larvae leave the tent where they feed on the newly forming leaves of their host trees. Favorite trees are wild cherry, apple, peach, and plum, although other trees are sometimes attacked.

By midsummer, the larvae pupate and turn into yellowish brown moths. The moths mate and lay clusters of eggs which will hatch the next spring to start the cycle over again.

Some people, it seems, do not like the sight of a group of happy campers — at least of the insect variety—so they try to dispose of the little beasts. If the tree under attack is small, one approach is to prune the 1imb with the web and worms and destroy it. Several insecticides can also be used to kill the caterpillars. However, treating large trees with insecticide requires specialized equipment, so it may be necessary to hire a professional.

In general, the feeding of tent caterpillars will not cause permanent harm to a tree. Usually the tree will have time to leaf out following the feeding. However, defoliation by tent caterpillars in two or more consecutive years could stress the plant and warrant control.

So the damage caused is more to the aesthetics of the tree and the pride of the owner. However, some people take the approach that a few insect tents in a tree are an interesting biological event -- especially if they can't be reached with the pruning shears.


Writer: Tom Turpin
Editor: Carol McGrew