Oak: Oak ribbed casemaker
Photo by: A.L. Antonelli
Biology
Oak ribbed casemaker larvae mine and skeletonize leaf tissues. Young larvae feed inside leaves, chewing away tissues and leaving a linear mine. Older larvae feed on the underside of leaves, leaving only the upper surface and veins, which turn brown. Severely damaged leaves may be almost transparent.
The mature larvae are about 1/4″ long, and pale yellow to green. Immature larvae make flat, white, circular cocoons, while cocoons of mature larvae are white, with distinctive longitudinal ribs. The latter can be found on leaves, twigs, or other nearby objects.
The adult moth emerges from the ribbed cocoons. It is mottled white, brown, and black with a wingspread of about 1/3″. The oak ribbed casemaker is reported on California white (valley) oak (Quercus lobata) and coast live oak (Q. agrifolia).
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!
- Natural enemies probably help keep populations in check. Avoid use of broad-spectrum insecticides which kill beneficial insects.
Chemical Management
IMPORTANT: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- Apply in summer when caterpillars are first active.
- Bacillus thuringiensis (Bt) will control leafrollers only if they are actively feeding.
- 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.
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.