Imported cabbageworm larvae are commonly parasitized by a wasp, Apanteles glomeratus, and pupae by another wasp, Pteromalus puparum. Larvae of the diamondback moth are parasitized by a wasp, Diadegma insularis. Larvae will already have caused some damage before these parasitoids kill them, but parasitoids break the life cycle by reducing the number of caterpillars changing to the adult stage. Wasps of the Trichogramma group are egg parasitoids that kill these pests before they hatch and begin feeding. General predators that feed on cabbageworms as well as other pests are ground beetles, true bugs, syrphid fly larvae, spiders, lacewings, spined soldier beetles, yellowjackets, and paper wasps.
Virus diseases can infect and decimate imported cabbageworm and cabbage looper populations.
Cultural and Physical Control Destroy crop debris after harvest. Row covers prevent adults from laying eggs on plants. In small gardens, the worms can be hand-picked from plants. Chemical Control Insecticides are usually effective at controlling these pests, although populations of the diamondback moth in some areas have developed resistance to some insecticides. The biological insecticide B.t.