Forest tent caterpillar strikes again! Outbreaks in NC continue for the third year running

by | May 17, 2017

Warm days are approaching here in North Carolina and all things spring can be seen! Beautiful flowers budding, green grass in yards, and butterflies fluttering around in the sunshine are all things you can see outside. However, if you look hard enough, you may find a few other things outside in your backyard. One little critter may be the forest tent caterpillar!

Aerial surveys allow surveyors to see the extent of the forest tent caterpillar outbreak this year. This photo was taken during a May 9, 2017, flight. Image: B. Palmer, NCFS.

The forest tent caterpillar is about 2 inches long and is commonly described as having a line of penguin designs running down its back. Let’s be honest here, who doesn’t love a cute cuddly penguin? You are most likely to see them on picnic tables, decks and on tree trunks. Forest tent caterpillar’s host trees are hardwoods (e.g., maples, gums, oaks, tupelos, etc.). They are covered in what appears to be a fuzz that are actually hairs. Often, the caterpillars will be seen in bunches on a silken mat they spin on the trunk of the tree. They spend their time there resting or molting. They are a social insect that stay together until they go through the transformation to become a moth.

Currently in northeastern North Carolina, the forest tent caterpillar is wiggling right along. With the sun shining and summer on its way, the caterpillar is coming out in numbers. During an aerial survey in early May, N.C. Forest Service surveyors could see how expansive this year’s outbreak is. They estimated at least 660-800 acres were defoliated this year along the Roanoke and Chowan rivers. In addition to the larger defoliation spots, the surveyors noticed forest tent caterpillar activity in most bottomland areas in swamps and along creeks and rivers. They also noted that blackgum trees appeared to be the most affected.

This is typically nothing to be concerned with as forest tent caterpillars have cyclical outbreaks, meaning populations may peak for several years then subside. Usually, natural predators keep them under control. During an outbreak, the caterpillars can cause noticeable damage when they eat most (or all) of the leaves off a group of trees. If you notice a group of trees near you that are all missing most of their leaves, then the forest tent caterpillar could very well be the culprit. The adult moth doesn’t eat at all; it simply wants to find a mate.

Luckily, the damaging caterpillars are easy to control by removing the individuals and the silken mat off the tree. Although the caterpillars are harmless to humans, if you don’t want to touch them, you can use another mode of action. They can easily be removed by wiping them off with a glove, broom, or even a towel. Alternatively, you could opt to do nothing, as outbreaks typically subside after a few years and long-term damage to tree health is uncommon.

Remind all your friends and neighbors to keep an eye out for missing chunks of leaves from trees and to wipe the mats off to prevent loss. Cheers to keeping everyone’s yards looking happy and healthy this spring!

Written by guest blogger Luke Lolies, N.C. State University student