According to the Florida Department of Agriculture Consumer Services and the U.S. Department of Agriculture, Laurel oak, live oak, water oak, red oak and white oak are common hosts to the white marked tussock moth. Tussock moths can cause significant damage (growth loss) to deciduous trees but will seldom kill the tree.
Life Cycle of the Tussock Moth
During the winter season the moth is in its egg stage. The eggs hatch in early spring, and the larvae feed until May or June. In May or June they pupate (pupation takes place in a tan/gray silk cocoon). In approximately two weeks the adult emerges, and will live from two to four weeks. In southern climates there can be three generations of tussock moths in a single year. After the female emerges from her cocoon she will mate, and then lay her eggs on the old cocoon (she lays them in a mass of up to 300 eggs–the eggs are gray to white in color).
The mature larva (caterpillar) is approximately 1 to 1 ½ inches in length. The head is coral/red, and the body is a yellowish-cream color. It has black stripes along its back with dark tufts of hair over the head and at the end of the caterpillar. There are also short yellow or white tufts of hair on its back. The male moth has a grayish/brown body and darker brown wavy bands on the wings along with a white spot. The female is wingless and gray in color.
Symptoms of Infestation
You will begin to see small holes in leaves as the young larvae begin to feed on the leaves. As the larvae mature you will notice the edges of the leaves being eaten–they will eat an entire leaf, leaving nothing but the larger veins and midribs. (The larvae can defoliate an entire tree.) You may also notice falling frass. Frass is caterpillar excrement, which form dark pellets. You may notice cocoons in the crevices of the bark of the tree, or in other protected areas around the tree. Other possible signs are branch dieback or thinning of the crown of the tree.
The Florida Department of Agriculture states that “Predators, parasites, diseases, and unfavorable weather usually keep caterpillar populations at low levels. Outbreaks do occur, but generally subside after two or three years.” They suggest that maintaining a healthy tree after infestation/defoliation occurs will help in the recovery of the oak tree. You can also choose to use an insecticide when the larvae are small.
You should refrain from handling or coming in contact with the tussock moth caterpillar. The hair of the caterpillar has been known to cause an allergic reaction. If you do come in contact with the caterpillar, and have a severe reaction after being exposed to the larval hairs, you should seek medical treatment.