Cabbage and other members of the crucifer family such as broccoli, Brussels sprouts, rutabagas and kale are a favorite food source for caterpillars and worms that are prevalent in the fall. Luckily, there is a way to safely get rid of these little trouble makers before they turn your cabbage into Swiss cheese like the plant pictured below.
Look for products containing the active ingredient bacillus thuringiensis (BT). Common product names are Thuricide, Dipel, and Safer Caterpillar Killer. These products come in both liquid concentrates and dusts.
BT is a naturally occurring bacterium which affects worms and caterpillars. Early treatment is best, since BT is most effective on smaller worms and caterpillars. Once the worms and caterpillars ingest the BT, they will stop feeding and will die in 1-2 days. BT is considered safe for people, other wildlife and beneficial insects.
Today, I’m mixing up Thuricide liquid concentrate, which is sprayed using a pump sprayer, at a rate of 4 teaspoons per gallon.
Be sure to thoroughly spray the tops and bottoms of the leaf surfaces. BT degrades in sunlight, so it’s best to spray in late afternoon or early evening.
If the caterpillars or worms persist, repeat the spray every 5 days or according to labeled instructions.