More cole crop tips

Last week’s article featured some basic aspects of the vegetables in the cabbage family, better known as cole crops. These include cabbage, kale, collards, cauliflower, broccoli, and Brussels sprouts. We discovered that, as a group, these crops tend to be high in vitamins and low in calories, a dieter’s dream. We also learned the importance of growing these crops in nitrogen-rich soil from the very beginning to encourage fast-growing, healthy plants.

While each cole crop has its own particular issues, most pests and diseases are shared by the whole group. The most persistent problem you will encounter is a barrage of caterpillar species, with cabbage loopers being the most common. Cabbage loopers arise from the eggs laid on the undersides of cabbage leaves by small white butterflies. These pesky invaders work to get a taste of the young, tender foliage well before you do.

Fortunately, there are effective measures that can help control caterpillars. If you are so inclined, you can handpick the worms. Or, you can get the Trichogramma wasp to do the work for you. These wasps are parasites that lay their eggs on the caterpillar, and upon hatching, the wasp larvae kill the caterpillar by feeding on it until it dies. You can procure these wasps through mail-order gardening magazines.

Perhaps the surest and most familiar way to control the cabbage looper and his clan is by a preparation made from the naturally occurring bacterium, Bacillus thuringiensis, also known as BT. Sprayed onto the foliage and ingested by the caterpillars, it causes them to stop feeding and die, turning into mushy, dark brown blobs in a matter of days. BT is sold under several names, including Biotrol, Dipel, and Thuricide. For best results, this bacterial insecticide should be applied before the worms reach one-quarter inch in length. Carbaryl (Sevin) and other chemicals are also effective against cole crop caterpillars.

Another problem of cole crops is clubroot. This is a fungal disease that attacks the roots of all cole crops, rendering them unable to take up water and nutrients. It deforms the roots, making them appear enlarged and club-shaped. The best controls are to keep the pH of your soil above 6.5 and to refrain from planting any cole crops in an affected area for at least two years.

In addition to fungal problems, you should also watch for aphids attempting to feast on the foliage of young cole crops. They can be fairly easily controlled with applications of Orthene, Sevin, or insecticidal soap.

Another insect threat comes from flea beetles, about one-eighth of an inch long, which can also do serious damage to young cole crops. These beetles can cause problems all season long in most area andy thrive in hot weather. The best controls we have are insecticides such as rotenone, pyrethrum, and Sevin.

Keeping these potential challenges in mind, I hope these pointers will help you in your quest for healthy cole crops.

Tim Lewis is a Georgia Green Industry Association Certified Plant Professional, gardening writer, and former Perry High School horticulture instructor. He can be reached at (478)954-1507 or timlewis1@windstream.net.