Juniper: Juniper webworm
Photo by: A.L. Antonelli
Biology
The adult juniper webworm is a copper-brown moth with white bands on the edges of the front wings. The moth is about 1⁄2″ across.
The webworm caterpillars initially feed by mining inside leaves, then gather to feed in small colonies or nests of webbed foliage as they mature. They are yellowish to brownish with dark brown lines on the back and a dark head.
The caterpillars overwinter in the nest and resume feeding in spring. Fully mature caterpillars are about 1⁄2″ long.
Due to their habit of feeding deep in the plant canopy, damage may be easily overlooked. Damaged foliage turns brown and is covered with dirty webbing.
Management Options
See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.
Non-chemical Management
Select non-chemical management options as your first choice!
- Hand-pick caterpillars.
- Prune and destroy webs with caterpillars.
- Several natural enemies help control juniper webworm populations. Avoid use of broad-spectrum insecticides which may kill these predators and parasites.
Chemical Management
IMPORTANT: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- Applications made in late fall, winter or early spring at relatively low temperatures are effective against this pest.
- Use a spreader-sticker with liquid Bt formulations.
- 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
If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.
Additional Image
Photo by: K. Grey
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Evidence of noncompliance may be reported through your local Extension office.