How to Manage Pests

Pests in Gardens and Landscapes

Filbertworm—Cydia latiferreana, Filbert weevil—Curculio occidentis,Acorn moth—Valentinia glandulella

Acorn moths and filbertworms are larvae of small moths, which are commonly bronze, coppery, or reddish brown. Larvae are light brown, to whitish with a darker head and have three pairs of true legs. Filbert weevils are brown beetles with a long thin snout. Larvae are light brownish, yellow, or white. Filbert weevil larvae have no obvious legs, are relatively inactive, and may curl into a C shape if disturbed.

Identification of species

Damage

Larvae of filbertworms, filbert weevils, and acorn moths commonly infest oak acorns and may also damage other nuts, including almond and chestnut. Moth and weevil larvae make holes in acorns or nuts, bore inside and feed, destroying kernels. Tunnels inside acorns may contain whitish larvae. Insect-damaged acorns may become colonized by bacteria, causing drippy oak.

Solutions

No methods have been demonstrated to control these weevils and moths. Acorns on the shady side of trees are more likely to be attacked than those on the sunny side. The pests may reduce natural oak regeneration, but established trees are not damaged. If collecting acorns, inspect and discard damaged nuts before storing or planting them.

Adult filbert weevil
Adult filbert weevil

Damage to acorns
Damage to acorns


Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2014 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /PMG/GARDEN/PLANTS/INVERT/filbertworm.html revised: April 25, 2014. Contact webmaster.