The Richmond Register

Lifestyles & Community

July 16, 2013

What’s eating my cole crops?

RICHMOND — Are you seeing holes in the leaves of your cabbage or other cole crops? Cole crops are those that belong to the mustard family, such as brussels sprouts, cabbage, cauliflower, collards, kale, kohlrabi, mustard, broccoli, turnips and watercress.

 There are several insects that are destructive to cole crops. One is the imported cabbage worm which is a velvety green caterpillar. The moth of this species is white and commonly is seen during the day hovering over plants in the garden.

The cabbage looper is a plain brown moth that is active during the night and its caterpillar is what we commonly refer to as an inch worm. Diamond back moths are gray with a diamond pattern on its wing. Its caterpillar is a small, green, pale caterpillar that is pointed at each end.

The adult form of these insects actually causes no harm to the plants. The moths simply lay their eggs on the plants, insuring that the offspring will have a nice meal as they hatch out.

Although the caterpillars are small, they are very destructive. They can be even worse in fall plantings than those planted in spring.

 Harlequin bugs have also been a problem on cole crops this year. This insect is closely related to stink bugs and has red and black markings on its back.

 As soon as you see damage on your plants you should treat the affected plants with the appropriate insecticide or insecticidal soap. The moths listed above can all be treated using Bacillus thuringiensis (Bt). Bt is a microbial insecticide that contains the spores of a bacteria found in soil and is used to control caterpillars (moth or butterfly larva only). Bt will not work on the harlequin bug. Other organic options include spinosid or a pyrethin. Conventional insecticides include malathion and esfenvalerate (Bug-B-Gon). Be sure to read and follow the label any time you use any chemical in your garden. Remember, it is easier to control an insect when it is small. The larger it gets, the more difficult to control.

 After harvest, be sure to remove any leftover or excess plant debris to eliminate the possibility of pests overwintering in your garden.

Text Only
Lifestyles & Community