🥬 Cabbage Looper
Trichoplusia ni
It moves like an inchworm and eats like it hasn't seen food in weeks.
How to identify
Pale green caterpillar about 1.5 inches long with thin white stripes down its sides — and only three pairs of prolegs at the rear, which forces the famous looping, inchworm-style crawl. Adults are mottled brown moths with a tiny silver figure-8 on each wing.
Damage signs
Chews large irregular holes between leaf veins, often leaving nothing but the skeleton of the leaf. Frass pellets tucked into cabbage heads are the calling card — nobody wants bonus crunch in their slaw.
Non-chemical controls
- Cover brassicas with floating row cover from transplant day — if the moth can't land, she can't lay eggs.
- Handpick loopers in the evening and feed them to the chickens (they consider it a delicacy).
- Apply Bt (Bacillus thuringiensis) to leaf undersides — caterpillar-specific and safe for everything else.
- Release Trichogramma parasitic wasps, which lay their eggs inside looper eggs and stop the problem before it hatches.
- Interplant with thyme, dill, or chamomile to repel egg-laying moths, and till under crop residue where pupae hide.
Nerdy fact: The looper's looping walk isn't a style choice — it's missing the middle prolegs that other caterpillars have, so it has to hump its back to move. It's doing the best it can with what evolution gave it, and what evolution gave it is a big appetite.
Still not sure this is your culprit? What’s Eating My Plant? narrows the suspects from what you actually see on the plant.