Loopers are green caterpillars up to about 1 1/2" in length. They may have pale or dark stripes along the body. They are distinguished by their characteristic looping or "measuring-worm" movement. Loopers feed on leaves of many plants, chewing holes in the leaves or feeding along leaf margins. The adult of the alfalfa looper, a species common on raspberry, is a mottled brown moth with silver markings. Wingspan is approximately 1 1/2". The primary damage caused by loopers is the contamination of harvested fruit.

Management Options

Non-Chemical Management

Hand-pick and destroy any caterpillars or cocoons found on leaves.
Natural enemies of caterpillars include predacious beetles, parasitic wasps, and birds. Avoid use of broad-spectrum insecticides when possible to conserve beneficial insects.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

Apply to control loopers when first noticed. Use a spreader-sticker with liquid Bt formulations.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

Bonide Captain Jack's Deadbug Brew R-T-U [Organic]
Active ingredient: spinosad (spinosyn A+D) | EPA reg no: 4-472
Bonide Thuricide BT Conc
Active ingredient: Bacillus thuringiensis subsp. kurstaki | EPA reg no: 4-226
Safer Brand Garden Dust RTU [Organic]
Active ingredient: Bacillus thuringiensis subsp. kurstaki | EPA reg no: 36488-25-42697
This list may not include all products registered for this use.

Images

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Caption: Cabbage looper Photo by: Unknown
Caption: Celery looper pupa Photo by: A.L. Antonelli
Caption: Alfalfa looper adult Photo by: OSU slide library

WSU Extension

Hortsense