Cabbage Worms

Also known as: Imported cabbageworm, cabbage looper, diamondback moth

Identification

Green caterpillars on brassicas. Imported cabbageworm: velvety green, sluggish. Cabbage looper: moves in looping motion. Diamondback moth larva: small, wriggly, drops on silk thread.

Damage

Chewing — consume brassica leaves, leaving large ragged holes; bore into cabbage heads

Best Organic Solutions (Ranked)

Solutions ranked by reliability tier — start with Tier A options.

Bacillus thuringiensis (Bt) Tier A

Btk — apply when caterpillars are small

Spinosad Tier A

Broader spectrum — gets all three species

Biological Controls

Trichogramma wasps (egg parasitoids), braconid wasps, green lacewing larvae

Prevention

Row covers from planting through harvest (brassicas don't need pollination). Bt preventive spray every 7-10 days during butterfly season.

Common Mistake

Not checking under leaves — egg clusters and small caterpillars hide on leaf undersides.