Gardening Articles: Edibles :: Vegetables
Cole Crop Diseases and Pests
by National Gardening Association Editors
Disease and insects can cause problems for your cole crops. Here's a list of the most common ones to look out for, and some ideas for control.
Lifeless, yellowish green color appears in plant (especially cabbage) two to four weeks after transplanting. Caused by a fungus that lives in the soil indefinitely. Especially troublesome in wet areas during hot weather. Use resistant varieties (indicated on the seed packet by the initials "YR"), plant on raised beds if drainage is a problem and rotate crop every year.
Caused by a fungus, this disease infects young plants, causing them to wilt because it rots away the stems. As the disease progresses, dark, sunken areas develop on the stems. Disease spreads in humid, rainy weather. Crop rotation and good garden sanitation are the best prevention.
A bacteria that can invade plants at any stage, blackening veins and affecting head formation. In severe cases, no head will form, or the existing head will rot. Rotate crops and remove plant debris. Cabbage and cauliflower are more susceptible than are broccoli or Brussels sprouts.
Swelling of roots caused by a slime mold that lives in the soil. Crop rotation is the best remedy and prevention. This disease doesn't thrive in alkaline soil, so adding lime to acid soils to raise the pH above 7.2 may help.
Primarily a southern disease caused by nematodes. Knots form on smaller roots and nearer the tips than clubroot. Crop rotation can help somewhat, and in sunny, warm parts of the country a technique called soil solarization also works well. Check with your county extension agent for control techniques appropriate for your area.
Some diseases, including several bacteria and fungus-caused wilts, cannot really be checked once they appear. Other diseases may be slowed by applying a fine sulfur dust or other organic fungicide to the plants. The best way to avoid diseases in the cabbage family, and in all your vegetables, is to stop trouble before it hits.
Keeping Bugs Out
Insects seem to plague spring-planted cole crops more than some other vegetables. This isn't because bugs would rather chew on broccoli than beans. It's partly because many insect populations emerge -- hungry -- early in the season. Often, your cole crops are the only food in sight. Also, the distinctive odor of cabbage-family vegetables may make them especially easy prey for insects.
One way to cut down on insect problems is to depend largely on the fall garden for your supply of cole crops. Insect populations are generally past their peak by the end of the summer, and increasingly cool temperatures discourage those that remain. You can also encourage insect-eating birds such as martins by providing a bird house in the garden.
Learn to recognize harmful insects (listed below), and make daily visits to your garden to pick off or destroy any unwanted pests before they ruin large amounts of your crops.