Pieris rapae
Larvae of the imported cabbageworm butterfly. One of the most common pests of brassica crops, feeding on leaves and contaminating heads with frass.
Velvety green caterpillars up to 1.25 inches with a faint yellow stripe. Adults are white butterflies with black wing tips and 1-2 black spots.
Irregular holes in leaves. Tunneling into cabbage heads. Green frass (droppings) on leaves. Stunted or unmarketable heads.
3-5 overlapping generations per year. Adults lay single yellow eggs on leaf undersides. Larvae feed for 2-3 weeks, pupate on plants or nearby structures.
Floating row covers from transplanting. Interplant with strong-scented herbs (thyme, sage). Attract beneficial insects. Remove crop debris promptly.