NC State Extension Publications

Descrition and Biology

Skip to Descrition and Biology

The Asiatic oak weevil, Cyrtepistomus castaneus, is a small (1/4 to 1/3 inch long), broadnosed weevil. It is usually greenish-gray although if its scales are worn away, some appear reddish-brown. It was introduced into the United States in 1933 (New Jersey) and now occurs throughout much of the East. Small, legless grubs associated with the roots of hardwood trees survive the fall, winter, and early spring. The grubs pupate and new adults emerge during the spring to feed on the leaves of oaks and chestnut. Asiatic oak weevils emerge in May and become most abundant in late June and early July. They feed on the margins of leaves, sometimes devouring everything but the main veins. This weevil takes shelter in leaves tied together by caterpillars. The weevils start laying eggs in soil in July and continue on into early fall. Asiatic oak weevils are sometimes a household pest because they invade houses apparently for hibernation quarters.

Asiatic oak weevil

This is a typical Asiatic oak weevil before its scales have worn off.

Asiatic oak weevils

Asiatic oak weevils usually feed from the leaf margin inwards.

his Asiatic oak weevil has j

This Asiatic oak weevil has just begun to feed.

Host Plants

Skip to Host Plants

Asiatic oak weevils feed primarily on oaks and chestnut although they have been reported from other woody plants. Adults fed red oak and black oak leaves lived longer and laid significantly more eggs than weevils fed white oak or sugar maple

Residential Recommendations

Skip to Residential Recommendations

The Asiatic oak weevil likely has not developed resistance to insecticides. If a specimen tree is small enough to spray, and if the tree is heavily infested, just about any insecticide labeled for landscape use should give adequate control.

Author

Professor Emeritus
Entomology & Plant Pathology

Publication date: July 23, 2019
Revised: Oct. 24, 2019

N.C. Cooperative Extension prohibits discrimination and harassment regardless of age, color, disability, family and marital status, gender identity, national origin, political beliefs, race, religion, sex (including pregnancy), sexual orientation and veteran status.