Have you ever seen a caterpillar with long hairs that stick out like two black horns on its head, one black horn on its tail, and four hairy mohawks on its back? If so, you probably encountered a tussock moth caterpillar. Depending on the species, their colors can range from dark gray to light gray, white, or yellow. The word “tussock” literally means a tuft or clump of hairs, feathers, or grass.
This is one of the most unusual native caterpillars you might encounter in Georgia. There are several different species commonly found here including the fir tussock moth, whitemarked tussock moth, definite tussock moth, and milkweed tussock moth. The larvae (caterpillar stage) of tussock moths occasionally feed on almost any species of hardwood and conifer tree. Oak trees appear to be a favorite host in Georgia as well as cherry, hackberry, and willow. However, whitemarked tussock moth caterpillars have been reported from plant species in over 116 genera.
The tussock moth is one of several stinging caterpillars that are common in our area. Other stinging caterpillars include the saddleback, puss moth, hag moth, Io moth, and spiny oak slug caterpillar. Most of the uriticating setae (stinging hairs) are found on the back of the tussock moth in the four tussocks or clumps of hairs that look like mohawks. There are also some stinging hairs found in the long, black plume hairs on the head and tail. These stinging hairs are barbed with microscopic hooks that are attached to a venom gland at its base.
Dermatitis due to the stinging hairs of tussock moth caterpillars has been reported from day-care centers and elementary schools when children play with these colorful, attractive caterpillars. Contact with the cocoons can also produce the same symptoms even after cocoons are a year old. Handle tussock moth caterpillars with gloved hands to avoid an uncomfortable rash.
Children should be taught not to handle caterpillars unless they can recognize harmless caterpillar species. Some examples of hairy caterpillars that are safe to handle include the banded woolly bear and eastern tent caterpillar. Wearing long-sleeved shirts and long pants will prevent accidental brushes with stinging caterpillars when pruning trees and shrubs or just taking a stroll through the woods. Our office has confirmed several calls, samples, and pictures of tussock moth caterpillars in recent weeks.
The adult moths lay eggs and can produce two or three generations per year. After hatching, the young larvae spin a silk thread that they use to “balloon” for dispersal to new locations. This ballooning method of dispersal is used by many types of caterpillars and even spiders.
Although the caterpillars of tussock moths feed on the leaves of many different tree species, the damage is usually insignificant. By the time they might defoliate an entire tree, we’re usually approaching the fall when trees naturally start shedding leaves. Therefore, we do not recommend spraying trees or shrubs for these types of caterpillars. Also, from a practical standpoint, it would be difficult to safely spray an insecticide into the canopy of a tall tree.
Paul Pugliese is the Extension Coordinator and Agricultural & Natural Resources Agent for Bartow County Cooperative Extension, a partnership of The University of Georgia, The U.S. Department of Agriculture, and Bartow County. For more information and free farm, lawn, or garden publications, call (770) 387-5142 or visit our local website at extension.uga.edu/bartow.
