NC State Extension Publications

Description and Biology

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The cecropia moth, Hyalophora cecropia, is our largest moth. It is in the family of giant silkworm moths, so called because the caterpillars spin tough, brown cocoons of silk and because the caterpillars tend to be large. They overwinter as pupae in these cocoons attached to the twigs of the trees on which they feed. The following spring the moths emerge to mate and lay about 100 white and brown mottled eggs in small groups on the stems and foliage of a variety of hard wood trees particularly maple, cherry, and birch. Although the female moths lay many eggs, their caterpillars are never abundant perhaps because birds find them to be highly attractive for food. Newly hatched caterpillars are tiny, black, and spiny. Over the course of the summer, the caterpillars grow to 4 inches long and are pale green. The caterpillars have four reddish knobs on the thorax and sixteen yellowish knobs in pairs along the back. They also have blue knobs around the insect. All of the knobs have black spikes. Cecropia moths lack functioning mouthparts and live for about two weeks. There is only one generation per year.

Dorsal view of cecropia moth.

Cecropia moths have up to a six inch wingspan.

A newly emerged cecropia moth.

A newly emerged cecropia moth.

A cecropia moth caterpillar

A cecropia moth caterpillar bunched up.

cecropia moth caterpillar stretched

A cecropia moth caterpillar stretched out.

Cecropia moth cocoon

Cecropia moth cocoon are spun from tough, brownish silk.

Host Plants

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Cecropia moth caterpillars feed on primarily on birch, cherry, and maple. They do occasionally feed on other trees. They are rarely abundant enough to cause any noticeable damage.

Residential Recommendation

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Although the female moths lay hundreds of eggs, their caterpillars are never abundant perhaps because birds find them to be highly attractive as food. No control measures seem to be needed.


Professor Emeritus
Entomology and Plant Pathology

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Publication date: Nov. 19, 2012
Revised: Sept. 18, 2019

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