Eastern tent caterpillars (Malacosoma americanum), or tent worms, are more of an eyesore or slight nuisance rather than an actual threat. However, getting rid of tent caterpillars is occasionally necessary. We can look at how to prevent tent worms and how to kill tent worms, if necessary.
About Tent Worms
Although often confused with fall webworms, tent caterpillars are quite different. Tent worms are active in early spring while webworms become active near fall. Tent worms make their tent-like nests in the forks of branches while webworm nests are located at the ends of branches. Fall webworms also enclose foliage or leaves within these nests. Tent caterpillars do not.
Tent worms prefer wild cherry trees and other ornamental fruit trees. They will, however, nest in ash, willow and maple trees as well. Other than their webs making trees appear unsightly, tent caterpillars rarely cause major problems. However, large colonies can significantly defoliate trees, as they feed on the leaves. This usually does not kill trees, which generally develop new leaves, but may make them more susceptible to disease and other problems. Tent caterpillars may also snack on nearby plants.
When tent caterpillar removal is necessary, the nests or egg cases can usually be picked out by hand. Egg cases can be seen easily once leaves drop from trees in fall. Larger nests can be removed by winding them around a stick or pruned out and destroyed.
The best time for tent caterpillar removal is early morning or evening while they’re still likely to be in the nest. Introducing natural enemies, such as various types of parasitic wasps, can also help reduce tent worm numbers. Creating a welcoming environment for birds is also an excellent tent caterpillar home remedy.
How to Kill Tent Worms
Sometimes getting rid of tent caterpillars means killing them. While small infestations can be taken care of by dropping the nests into soapy water, contact insecticides work best for larger populations. Bacillus thuringiensis (Bt) is the most effective. Since this is a selective insecticide, it kills tent caterpillars while remaining safe to other wildlife. Apply spray directly to foliage and tent worm nests.
Getting rid of tent caterpillars is easy if you follow these basics steps. Your trees will return to their former beauty in no time at all.