Loopers

Loopers arch their backs as they crawl. Cabbage loopers usually have a narrow, white stripe along each side and several narrow lines down the back. Eggs are dome-shaped and laid on the undersurfaces of older leaves. Adult moths have brown, mottled forewings marked in the center with a small, silver figure-8.

Young larvae feed primarily on the undersides of lower leaves, skeletonizing them. High populations can damage seedlings severely enough to kill them or slow growth enough to inhibit uniform maturing of the crop. Older larvae may burrow into the head from the top.

Primarily an early-season pest in inland desert growing area, where loopers are managed with treatments.

Loopers have many natural enemies that often keep populations below economic thresholds. Maximize the use of these natural enemies by limiting treatments, especially between thinning and heading.

Biological control and sprays of Bacillus thuringiensis are acceptable for use on organically certified crops.

Look for signs of looper feeding: plants with holes in outer leaves, feces, caterpillars feeding on edge of hole. Check fields twice a week once seedlings emerge.

Treat seedlings or small plants if populations of medium-sized to large loopers are large enough to stunt growth. Treat well established plants only if you find an average of more than one-half larvae per plant. For cabbage looper control, the best time to apply insecticide is in the afternoon.