How to identify
- Soft green caterpillar matching the leaf color
- White butterflies fluttering over the bed in daytime
- Ragged holes and green frass on leaves
Damage: Chewed foliage; frass in broccoli heads; seedlings can be ruined.
Control methods
- Cover beds with floating row cover from transplant day until flowering crops need pollinators (brassicas grown for leaves can stay covered).
- Hand-pick caterpillars and crush eggs on leaf undersides.
- Rotate brassicas; clear crop debris after harvest.
What products to use
We list product types and what to check on the label — not brand rankings, prices, or “we tested” claims. Always follow the label for your crop, and prefer the least disruptive option that works.
Bt (kurstaki)
When: Active feeding on leaves
Look for: Labeled for cabbageworms on cole crops; reapply after rain per label
Spinosad (food-crop label)
When: Heavy pressure when Bt is not enough
Look for: OMRI-listed options if you want organic; spray evening to reduce bee exposure