Eastern Tent Caterpillar
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Eastern Tent Caterpillars form silk-webbed nests in branches or where main stems fork. The colony uses the nest for protection against predators and the elements. The nest is built in layers. As the caterpillars increase in size they add additional layers of silk to the nest.
Eastern tent caterpillars generally attack understory trees, particularly crabapple, wild cherry, and apple, but also will feed on peach, pear, plum, rose, hawthorn, and others. The larvae often eat all the leaves off a tree. Although this damage is unsightly and worrisome, it usually only weakens the tree after three or more years of more than 50% defoliation.
The caterpillars are hairy, black with white stripes with narrower brown and yellow line on the sides and blue spots. When full grown, they are about two inches long. Caterpillars are the only stage which cause feeding damage. After about six weeks of feeding and growing the young spin white or yellowish white cocoons, about one inch in length.
Adults are reddish brown moths with stripes on the forewings and have a wingspan of 1" - 1 1/2". The adults mate and females lay about 200 eggs in a ring around twigs, laying on a foamy secretion which dries to a hard, protective shell. The eggs overwinter and hatch out as tiny larvae in early spring usually early to mid April.
If you have potential tree hosts, careful observation and hand control may be all you need. In fall, winter, and early spring look for egg masses and cut or scrape them off and either burn or soak them in soapy water. In early spring, tear out nests by hand or with a garden tool and destroy the young caterpillars. This can be easily accomplished by dropping the nest parts and caterpillars in a pail or dishpan of soapy water. People often burn the nest out of the trees, but we do not recommend this method because of the safety hazard.
There are several natural enemies of the tent caterpillar. A parasitic fly attacks full grown caterpillars. This fly looks like a housefly, but is twice as large, has a light gray thorax with three black stripes. The fly maggot consume the caterpillar internally and kill it as a pup (cocoon). That tent caterpillar may have eaten your tree leaves, but it won't leave young to do it next year. Ground beetles and predaceous wasps also eat tent caterpillars, as do various birds, most notably Northern orioles. The birds' hanging sack-like nests mean you won't have to worry about tent caterpillars; orioles have been known to eat entire infestations.
Acephate, carbaryl, malathion, and B.t. are the recommended insecticides.Bacillus thuringiensis (B.t.) is the most environmentally sound solution. If you own an orchard, try to clear out nearby wild cherry trees, if possible. If your trees have been defoliated, water and fertilize them. One inch of water, applied once per week is recommended.
For a complete listing of suggested control options for all home, yard and garden insect pests, check with your local Extension Service, found under local government in the phone book.
Read and follow instructions on the pesticide label. Heed all warnings. Check with your physician if you have any concerns regarding your personal health risk. Revised by Tom Ellis, M.S., Department of Entomology
MSU 2003
Eastern tent caterpillars generally attack understory trees, particularly crabapple, wild cherry, and apple, but also will feed on peach, pear, plum, rose, hawthorn, and others. The larvae often eat all the leaves off a tree. Although this damage is unsightly and worrisome, it usually only weakens the tree after three or more years of more than 50% defoliation.
The caterpillars are hairy, black with white stripes with narrower brown and yellow line on the sides and blue spots. When full grown, they are about two inches long. Caterpillars are the only stage which cause feeding damage. After about six weeks of feeding and growing the young spin white or yellowish white cocoons, about one inch in length.
Adults are reddish brown moths with stripes on the forewings and have a wingspan of 1" - 1 1/2". The adults mate and females lay about 200 eggs in a ring around twigs, laying on a foamy secretion which dries to a hard, protective shell. The eggs overwinter and hatch out as tiny larvae in early spring usually early to mid April.
If you have potential tree hosts, careful observation and hand control may be all you need. In fall, winter, and early spring look for egg masses and cut or scrape them off and either burn or soak them in soapy water. In early spring, tear out nests by hand or with a garden tool and destroy the young caterpillars. This can be easily accomplished by dropping the nest parts and caterpillars in a pail or dishpan of soapy water. People often burn the nest out of the trees, but we do not recommend this method because of the safety hazard.
There are several natural enemies of the tent caterpillar. A parasitic fly attacks full grown caterpillars. This fly looks like a housefly, but is twice as large, has a light gray thorax with three black stripes. The fly maggot consume the caterpillar internally and kill it as a pup (cocoon). That tent caterpillar may have eaten your tree leaves, but it won't leave young to do it next year. Ground beetles and predaceous wasps also eat tent caterpillars, as do various birds, most notably Northern orioles. The birds' hanging sack-like nests mean you won't have to worry about tent caterpillars; orioles have been known to eat entire infestations.
Acephate, carbaryl, malathion, and B.t. are the recommended insecticides.Bacillus thuringiensis (B.t.) is the most environmentally sound solution. If you own an orchard, try to clear out nearby wild cherry trees, if possible. If your trees have been defoliated, water and fertilize them. One inch of water, applied once per week is recommended.
For a complete listing of suggested control options for all home, yard and garden insect pests, check with your local Extension Service, found under local government in the phone book.
Read and follow instructions on the pesticide label. Heed all warnings. Check with your physician if you have any concerns regarding your personal health risk. Revised by Tom Ellis, M.S., Department of Entomology
MSU 2003
