NC State Extension Publications

Description and Biology

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Buck moths, Hemileuca maia, are so called because they fly during the day during deer season. Other species of moths usually don't fly during the day. Buck moths are in the family of the giant silkworms but differ from the others in that the female moths lay their eggs in the fall for next year's crop of caterpillars. Eggs are laid in a tight mass around an oak twig. The rest of the giant silkworm moths emerge in the spring and summer and lay eggs from which caterpillars hatch in only a few days. A third difference is that buck moth caterpillars have stinging hairs that can cause a severely painful reaction to folks who are sensitive to the urticating fluid contained in the hairs. With some folks these stings may require medical attention. Buck moths are dark gray to black with a conspicuous white band on each wing. Each band has a noticeable eyespot. The wingspan is 2 to 3 inches (males are smaller than females). The tip of male moths is rusty red. Moths emerge in the morning and mate in early afternoon. Winter is spent as eggs that hatch the following spring. Young caterpillars feed in groups. Older buck moth caterpillars are black and spiny although they may be covered with tiny white spots to the point that they appear almost white. The spines are grouped on bumps arranged in multiple rows along the body. The spines on top are longer and more branched. These caterpillars grow to almost 2 ½ inches long. Mature caterpillars crawl down and seek shelter in leaf litter or a few inches underground if the soil is soft enough. Then caterpillars molt into pupae and moths emerge from the pupal skins from September through December, although some may not emerge for a year or two. We have only one generation per year.

buck moth

The eye spots on the wings of buck moths are sometimes not so evident.

Buck moth eggs

Buck moth eggs are laid in a tight mass around an oak twig.

Young buck moth caterpillars

Young buck moth caterpillars feed gregariously.

Older buck moth caterpillar

Older buck moth caterpillars tend to be solitary.

Buck moth caterpillars pupa

Buck moth caterpillars pupate in leaf litter or in loose soil.

Host Plants

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Buck moth caterpillars feed primarily on oaks including scrub oak, live oak, blackjack oak, and dwarf chestnut oak. Buck moths do not feed.

Residential Recommendations

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Buck moth caterpillars are not particularly resistant to pesticides. Bacillus thuringiensis (on young caterpillars), Sevin, or some other properly labeled insecticide should give more than adequate control.

Buck moth caterpillar stings cause immediate pain that then spreads to nearby lymph nodes. Swelling and redness can last over a week. Wash the site immediately to remove any loose spines and allow it to air dry. Any remaining spines can then be removed with an adhesive such as duct tape. Not handling caterpillars that have spines is one of the best ways to avoid receiving stings.

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: Jan. 25, 2017
Revised: Sept. 11, 2019

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