Common Cabbage Problems
Club root, Black Rot, Black Leg, Wirestem, Alternaria Leafspot and Downy Mildew: Best control for this is to plant disease-resistant varieties.
Aphids, Cabbage Loopers, Imported Cabbageworm, Cutworms, Flea Beetles, and Diamond Back Moth: The biggest problems occurring right after planting are cutworms and slugs. To deter cutworms, fit cutworm collars around transplants. To control slugs, lay slug pellets on dishes around cabbage or spread out large amounts of wood ashes.
Cabbage Worm: a destructive caterpillar that chews on leaves and heads. They can be picked off by hand or blasted with a garden hose. Dipel and Thuricide are organic controls that transmit a disease lethal only to caterpillars.
Root maggots are the most difficult pests to control organically. The best remedy is to plant cabbage through black plastic mulch and fit a stiff, cardboard collar around the planting hole. This way the fly cannot enter the soil around plants to lay her eggs. Broad spectrum chemicals like Sevin and Malathion are widely used by commercial growers and are effective against most cabbage pests. Some of the milder organic sprays and dusts such as rotenone and pyrethrum offer good control, especially when used in combination.