NC State Extension Publications

Description and Biology

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The yellownecked caterpillar, Datana ministra, is one of the most frequently reported pests of oaks, birches and other hardwoods. Young caterpillars are small green worms that grow into medium orangish worms with yellow stripes and then into large (about 2 inches long), black- and yellow-striped caterpillars with black heads and reddish prolegs. The body is covered by long, fine, white hairs. Behind the head is a bright yellow to orange patch from which this insect's name is derived. Moths emerge from the soil during June and July. Male moths are sometimes attracted to lights. Moths are reddish to cinnamon brown, and the forewings have irregular, fine dark lines. The wingspread is about 2 inches. Females lay their tiny, white eggs in masses — sometimes a 100 or more — on the lower surface of leaves. The larvae typically feed in groups near the ends of the twigs and branches. When disturbed the whole group often elevates both ends of the body, a behavior that predators might find intimidating. In August and September, the mature caterpillars burrow into the soil 2 to 4 inches and pupate to spend the winter there. There is one generation per year.

Yellownecked caterpillar moth

Yellownecked caterpillar moths are in a group called "handmaid" moths.

Yellownecked caterpillars feed on a wide variety of host plants.

Yellownecked caterpillars feed on a wide variety of host plants.

Young yellownecked caterpillars usually feed in groups.

Young yellownecked caterpillars usually feed in groups.

Mature yellownecked caterpillar

Mature yellownecked caterpillars are about two inches long.

Host Plants

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Oaks are among the favorite hosts of yellownecked caterpillars, although it also feeds on basswood, birch, elm, honeylocust, oak, maple, mountain-ash, walnut and witchhazel. This insect is also destructive on blueberry, apple, and other fruit trees.

Residential Recommendations

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Yellownecked caterpillars are parasitized by tachinid flies and are preyed upon by insects and birds. Because yellownecked caterpillars feed gregariously, they can be dislodged from low branches and trampled underfoot if one has the stomach. Sevin or one of the other insecticides labeled for home use should give adequate control. Once the caterpillars mature and crawl about seeking a place to dig into the soil, they are much less susceptible to insecticides.

References

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For assistance with a specific problem, contact your local Cooperative Extension Center.

This Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology and Plant Pathology

Publication date: Feb. 3, 2017
Revised: Oct. 24, 2019

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