Have trouble every year with white butterflies laying eggs on my cabbage plants and destroying a lot of the heads. Do you think cheesecloth staked over the plants would not hinder sunlight, and keep those pesky bugs from laying eggs? Bill S., ND
Answer: Row covers will work to keep out any flying pests but I would use the commercially available fabric – a translucent, spun fabric, and not just cheesecloth, as the holes could be large enough for some pests to get through. However, you would need to make sure the plants are covered when the moths are active in your area. You will still need to check for other forms of crawling pests.
Another method of control is to hand pick and destroy the caterpillars. Cabbage loopers and cabbageworms in the larval stage look similar; both are green caterpillars. They both feed on the underneath side of the leaves and this is also where you would find the eggs. You may also find cutworms, a grayish or brownish grub that feeds not only on stems and leaves but near the ground, feeding on developing cabbage heads; flea beetles leave small round holes; and cabbage aphids will infest the undersides of the plants, causing wrinkled and curled leaves, stunting plants and killing the heads.
Next season plant some Sage herbs next to your cabbage plants. The White Cabbage Butterfly hates the smell of Sage and will stay away from your cabbage!
If you’re not concerned about a strictly organic process, you can spray the plants with pesticides, making sure each pest is listed on the label. Start with something containing malathion. You can also use BT (bacillus thuringiensis). Spray plants with a forceful stream of water to dislodge the insects and then treat with insecticidal soap; or to control aphids, release ladybugs into your garden. To help control the loopers and similar worms, you can apply neem oil or hot pepper wax or a naturally occurring chemical called rotenone. It’s also possible to create a barrier around each plant with Diatomaceous Earth. Oregano or tansy can be used to discourage flea beetles, and adding tinfoil under plants to reflect sunlight upwards is said to deter aphids.
It’s best to always determine exactly what is “bugging” your crop, then treat…and treat at the appropriate time.
Best of luck, Karen