Juniper: Spruce spider mite
Photo by: A.L. Antonelli
Biology
Foliage of plants infested with spruce spider mites is often speckled, stippled, or bleached-looking. Severely damaged leaves or twigs may drop.
Some species of spider mites produce fine webbing on the plant. They may be a problem to control because of the dense foliage typical of ornamental junipers.
These mites are extremely small and are easily spread by wind, birds, and people. They overwinter as eggs on the host and can begin hatching as early as April or May.
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!
- predaceous mites and insect predators such as ladybird beetles may naturally control spider mite levels. Avoid use of broad-spectrum insecticides that kill these predators.
- Wash spider mites from plants with a strong stream of water.
- Keep plants healthy to increase pest tolerance.
- Switch to slow-release or lower-nitrogen fertilizers. High levels of nitrogen in the leaves can increase spider mite reproduction rates.
Chemical Management
IMPORTANT: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- Begin monitoring for spider mite in the late spring or especially during hot weather.
- 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: R. Maleike
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Evidence of noncompliance may be reported through your local Extension office.