Monitor cool-season crops for pests, such as aphids and various caterpillar species (cabbage loopers, cross-striped cabbageworm, and diamondback moth caterpillars). Properly identifying these pests will help in selecting control methods. For aphids, there are many natural predatory insects, such as lady beetle larvae, lacewings, syrphid flies, damsel bugs, and wasps. For more information on predatory insects, see HGIC 2820, Natural Enemies: Predators and Parasitoids. If additional control is needed for aphids, a commercially prepared insecticidal soap may be used. For more detailed information on insecticidal soap, see HGIC 2771, Insecticidal Soaps for Garden Pest Control. A naturally occurring bacterium, B.t. (Bacillus thuringiensis), may be used to control young caterpillars. As with all pesticides, read the label and apply at recommended rates and frequencies. Regardless of what pest you have, it is a good idea to maintain good sanitation in the garden. Always remember to remove any leftover plant debris at the end of the season. This will help reduce many over-wintering pest problems.
For more information see on cool-season vegetable garden pests, see HGIC 2203, Cabbage, Broccoli, and Other Cole Crop Insect Pests; and HGIC 2016, Integrated Pest Management for Cabbage Looper.