Cotoneaster: Cotoneaster webworm
categories: Cotoneaster Cotoneaster Insects Ornamentals Shrubs
revision date: 2023-12-02 09:17
Photo by: C.R. Foss
Biology
The cotoneaster webworm is a dark brown caterpillar, 1/4″ to 1/2″ long. It typically ties clumps of leaves together with webbing and feeds within the nests, skeletonizing leaves. The caterpillars feed during the summer and fall, overwintering in nests on the plant and pupating in the spring. The dark gray, night-flying adult moth emerges in the spring to lay eggs. The webworm is primarily a problem on Cotoneaster horizontalis (rock cotoneaster).
Management Options
Use Integrated Pest Management (IPM) for successful plant problem management.
Non-chemical Management
Select non-chemical management options as your first choice!
- Hand-pick and kill caterpillars.
- Prune out and destroy nests.
- Remove any overwintering nests found on the plant.
Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.
- Monitor plants and apply product when caterpillars first appear.
- Homeowners should not make foliar applications to trees over 10 ft tall.
- Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.
Approved Pesticides
Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
Additional Image
Photo by: S.J. Collman