How to Manage Pests

Pests in Gardens and Landscapes

Shield bearers—Coptodisca spp.

Larvae of more than one dozen species of shield bearers feed entirely within the leaves of plants, including apple, cottonwood, crape myrtle, oak, madrone, manzanita, poplar, and strawberry tree. The madrone shield bearer, Coptodisca arbutiella, attacks foliage of madrone, manzanita, and strawberry tree in Pacific Coast states. Adults are tiny silvery moths; mature larvae are black. The madrone shield bearer has one generation a year. Other species, such as the resplendent shield bearer, C. splendoriferella, on apple, have two generations a year.

Damage

In the fall, larvae hatch and begin mining leaves. In the late winter, mature larvae cut round or oval areas of mined foliage from the leaves, approximately 0.25-inch long. This portion of the leaf drops to the ground or is carried by the larva and fastened to the bark. High shield bearer populations cause leaves to develop numerous holes, like those made with a paper punch. Infested leaves may become partially necrotic and drop prematurely.

Solutions

No effective controls have been documented for most shield bearers in landscapes. Pick and dispose of infested leaves on small plants if damage cannot be tolerated. Spraying for shield bugs is not recommended. Much of their life cycle is spent within plant tissue protected from insecticides. Spraying disrupts the parasites that may help to limit shield bearer outbreaks to a short duration.

Poplar shield bearer larve
Poplar shield bearer larvae

Madrone shield bearer damage to manzanita
Madrone shield bearer damage to manzanita


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/shfollagemin.html revised: April 25, 2014. Contact webmaster.