NC State Extension Publications

Description and Biology

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The octotoma leaf beetle, Octotoma plicatula, was described by Fabricius in 1801 based on a beetle collected in “Carolina.” It is a brown to black, wedge-shaped, flattened beetle about 3/16 inches long. The upper surface is rough with bumps and ridges. Adults are active from May through August. The larvae are leaf miners in cow itch, Campsis radicans, and Lespedeza. In the leaves of cow itch, the larvae form winding mines, and excrement collects as a black spot at one end of the mine, usually toward the midrib or base of the leaves. They pupate inside the mines and the adults emerge sometime later. The pupae have unusual spines associated with the spiracles of abdominal segments 3, 4, and 5. Octotoma leaf beetles feed on the foliage of horse chestnut, ash, Ligustrum, and fringe tree. Adult octotoma leaf beetles have been reported from carrot flowers as well. The beetles chew long, narrow patches from the lower surface of leaves up to 13/16 inches long. These patches are often crescent shaped. Heavily damaged leaves may drop prematurely.

Ligustrum showing octotoma leaf beetle damage.

Ligustrum showing octotoma leaf beetle damage.

Octotoma leaf beetle on lower surface of ligustrum leaf.

Octotoma leaf beetle on lower surface of ligustrum leaf.

Octotoma leaf beetle

Octotoma leaf beetles are small, flat, and rough.

Host Plants

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Octotoma leaf beetles feed on the leaves of horse chestnut, ash, Ligustrum, and fringe tree. Adults have been reported from carrot flowers as well. Octotoma leaf beetles chew long, narrow, sometimes crescent shaped patches from the lower surface of leaves. Heavily damaged leaves may drop prematurely.

Residential Recommendation

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This beetle should not be resistant to pesticides, so just about any insecticide labeled for landscape use in home grounds should give more than adequate control.

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This Factsheet has not been peer reviewed.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

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Publication date: June 3, 2013
Revised: Oct. 7, 2019

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