Douglas Fir: Silverspotted tiger moth
Photo by: A.L. Antonelli
Biology
The caterpillars of the silverspotted tiger moth feed on the needles, often “tenting” branches with dirty-looking webs. Feeding occurs through fall and winter, with webs becoming more noticeable by spring.
The caterpillars can reach 1 1⁄2″ in length and are mostly reddish-brown with some blue-black or yellowish hairs. Adult moths are brownish or tan with distinct silver-white spots on the wings.
Minor infestations cause little harm to trees. Douglas fir is the preferred host, but the caterpillars will infest other conifers. Caterpillar hairs can cause skin irritation if they are handled without gloves.
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!
- Prune and destroy “tents” with caterpillars.
- Hand-pick (wearing gloves) individual caterpillars.
Chemical Management
IMPORTANT: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- Apply when caterpillars first appear or when damage is noticed in late fall or early spring.
- If Bt is chosen, be sure to apply when insect is feeding. Best time is when caterpillars are young.
- 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: L.W. Getzin
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Evidence of noncompliance may be reported through your local Extension office.