The collards (Brassica oleracea) are sprouting in your garden when you notice brown or white moths fluttering about the seedlings. Those cute little moths are the parents of the cabbage looper (Trichoplusia ni) and imported cabbageworm (Pieris rapae). If unchecked, the caterpillars eat your collards faster than you can harvest the leaves. Instead of pesticides, you can use a barrier method; if that fails, natural bacteria can help keep the worms from eating your crop of greens.
Place floating row covers - long sheets of lightweight materials that "float" above the crops -- over the developing plants to prevent the cabbage looper and imported cabbageworm moths from laying their eggs on the leaves. Although you covered your plants, you may find that a few moths managed to lay eggs and their caterpillars, also known as worms, are eating your collard greens. The University of California Statewide Integrated Pest Management Program recommends spraying cole crops like collard greens with Bacillus thuringiensis. This natural bacterium will infect and kill the worms in two to three days. Simply mix 2 to 4 teaspoons of the Bt concentrate with 1 gallon of water to manage cabbage loopers, or 1 to 3 teaspoons with 1 gallon of water for imported cabbageworms. Spray the tops and bottoms of the leaves thoroughly with the solution. Repeat every two weeks as needed until you harvest the plants.
- Clemson Cooperative Extension: Collards
- University of California Statewide Integrated Pest Management Program: Cole Crops -- Cabbage Looper
- University of California Statewide Integrated Pest Management Program: Cole Crops -- Imported Cabbageworm
- Bonide: Bacillus Thuringiensis (Bt) Thuricide Concentrate
- Colorado State University: The Use of Floating Row Covers
- John Moore/Getty Images News/Getty Images