Gardening Articles: Care :: Pests & Problems
Get A Head (page 4 of 4)
by Jack Ruttle
Cabbage Damage Control
Cabbages aren't bothered by many insects and are able to grow fast enough to recover quickly from damage. But there are four pests that can, at times, gain the upper hand.
Cabbage Maggot. This small fly is attracted to newly worked soil and lays eggs at the base of a cabbage stem or on the soil nearby. The root maggots that emerge feed on the roots for one to several weeks. The adults can lay eggs throughout the growing season. When there are more than 50 feasting on a single root mass, you'll begin to see wilting on bright days. Sometimes the plants keel over and die very quickly. Once maggots are working on the roots, there's little you can do. But it's fairly easy to prevent the insect from gaining entry. Cut 6- by 6-inch squares of tar paper and punch a hole in the center with a nail. Then make a slit from the hole to one edge and slip this shield around the seedlings at planting time, making sure it fits snugly around the stem. The adult fly will be unable to get near the stem and won't lay eggs there.
Cabbageworm. Several small pale butterflies lay tiny white eggs on the undersides of cabbage leaves, from which hatch voracious cabbage-colored caterpillars. The imported cabbageworm is widespread and around all season long. The cabbage looper and the diamondback moth, which produce small, green caterpillars that do similar damage, don't winter over in the North. They migrate from the South each year, reaching the northern tier states by late August or September. Loopers hunch up in a loop if you touch them; the others don'tAll these insects are fairly easily controlled with Bt sprays. Apply the bacterial insecticide before the worms reach 1/4 inch in length.
Aphids. In hot, dry springs and in the cooler weather of fall, aphid populations can get out of control. Aphids tend to cluster on the most nutritious areas of the plant--growing tips and leaf axils--where they are harder to reach with sprays.
Insecticidal soaps are very effective against aphids. Start spraying as soon as you see the first little pale green wedge-shaped pests.
Flea Beetles. Cabbage flea beetles, striped and about 1/8 inch long, can do serious damage to young cabbage plants. They are season-long pests in most areas, with no distinct gaps between generations. But they thrive in hot weather. The best controls we have for them are insecticides such as diatomaceous Earth and pyrethrum.
Jack Ruttle is a former senior editor at National Gardening.
Photography by National Gardening Association, Suzanne DeJohn/National Gardening Association (aphids and cabbageworm), Kansas Department of Agriculture-Plant Protection & Weed Control Program (rootmaggots), and USDA (flea beetle)