101 On Eastern Tent Caterpillars


The Eastern Tent Caterpillar will soon be active in many flowering trees and shrubs. These caterpillars are a native insect and their feeding habits are an aesthetic problem, due to the large silken tents that they create in the crotch of a tree or shrub.


Their larva have the capability to defoliate a tree in the spring and have the ability to move to other trees once they have finished defoliating the old one. If you are careful and very observant, you may even be able to see the egg masses laid on a branch last fall by the female. Each egg mass is about the size of a pencil, has a varnish-like color and contains 150 to 300 eggs.


Once the eggs hatch, the larva stays together to build their silken tent, usually in a major branch crotch. They stay inside the tent during inclement weather, but when they venture out, they leave behind a silken thread for other caterpillars to follow. The larva feed and grow over a six week period. If populations are large, they will move to nearby trees to continue their feeding. Once they are done feeding, they move off by themselves to look for an appropriate spot to pupate. This can be the underside of a leaf , fence board or other inconspicuous site. Their cocoons are about 1 inch long and spindle shaped. The pupation period lasts about 2 to 4 weeks.

eastern tent caterpillar

 The adults lead a much less notable life. This could be due to the fact that, like many other adult insects, their sole purpose in life is to mate, lay eggs and die. They are essentially a red hued moth with a wingspan of 2 to 2 ½ inches. They do not feed during their short lifecycle and the female lays her eggs on branches in July or August.

As previously mentioned, these larva have the capacity to defoliate a tree. However, the tree often recovers with a new set of leaves once the feeding is over. There can be some lasting effects on the tree if the feeding occurs every year, which may result in some die back at the top of the tree.

According to Cornell University in New York, major outbreaks of Eastern tent Caterpillars occur on a 10-year cycle, with minor outbreaks in other years.

One of the easiest ways to control Eastern tent Caterpillars is to remove the egg mass through pruning in the fall or early spring. If it is a minor outbreak and there is only one or two small tents in the tree, cut out the tent and dispose of it.

You can also use the broom handle of a small rake to destroy the tent so that predators, such as birds and wasps won’t lay their eggs on the larva. If left, predator’s eggs hatch and feed on the caterpillar’s larva.

Other control options include Bacillus thuringiensis var. kurstaki, a bacteria that will kill the larva. Commercially available insect control products will also take care of the larva. Always read and follow label directions when using any control products.

Eastern Tent Caterpillars are a fairly easy insect pest to control. Many tree and shrub insect pests require specialized equipment and products to achieve proper control.

Contact your local Spring-Green office to learn more about the ways that they can help improve your landscape and keep it from being damaged by numerous disease and insect pests.