Have you ever wondered why those pretty white butterflies hang around the garden? These are one of the culprits that are doing in your cabbage, broccoli, cauliflower and brussels sprouts. These happy white butterflies (actually Imported Cabbage Worms) are laying eggs on your plants.
There 3 main cabbage worms that will attack your plants are the Imported Cabbage Worm (Pieris rapae), Cabbage Loopers (Trichoplusia ni) and Diamondback Moths (Plutella xylostella). Imported Cabbage Worms are the white butterflies with the black spots (Image 1). Cabbage Loopers are the night flying brown mottled moths. The third cabbage worm that eats your cabbage and other plants is the Diamondback Moths. They are small and brownish with a turned up tail. All three have green larvae that will munch your cabbage, broccoli, cauliflower, lettuce, mustards, Bok Choy and kale.
The moths lay eggs on your plants. These eggs can hatch out in four to eight days, depending on how warm the eggs are. The eggs hatch out into little green worms (Image 2) that reach around an inch long at maturity. The worms will munch on your plants for 7-15 days then they will pupae. After a week or so, depending on the temperatures, the pupae hatches and the adult moth start the cycle all over again. The moths can winter over as pupae in the soil. By rotating your crops to a new spot every year and turning the soil in the fall and early spring to expose the pupae to the cold you can eliminate some of the pupae.
