Test Your Knowledge - October

Cabbage looper larva and feeding damage
Cabbage looper larva and feeding damage
David Cappaert, Michigan State University, www.insectimages.org

Yes! This is a cabbage looper.

Cabbage loopers are one of several different kinds of caterpillars that chew holes in leaves of cabbage, kale, collards, brussel sprouts and other cole crops.

Fortunately all these caterpillars can be dealt with in the same basic ways if damage is observed early. In small vegetable gardens you can handpick the caterpillars and dispose of them in soapy water. The organic pesticide, Bacillus thuringiensis (B.t.) works very well to control young caterpillars. The larvae or caterpillars do not die immediately, but they stop feeding shortly after ingesting B.t. spores. B.t. should be reapplied several times at 3 to 14 day intervals depending on plant growth rate, moth activity, and rainfall.

For best results using B.t. products:

  • Check plants frequently so that you can spray caterpillars while they are young.
  • Spray the parts of the plant on which insects are feeding thoroughly, including the underside of leaves. B.t. products must be eaten in order to be effective.
  • Treat with B.t.in late afternoon or evening, or on a cloudy day as B.t. breaks down in sunlight.
  • Be aware that B.t. does not kill immediately, but following treatment insects will stop feeding almost immediately.

Be sure that you have seen caterpillars and know that they are the culprit when observing holes in cabbage and leaves of related plants. Slug damage appears as very similar looking holes, but can be distinguished by the silvery trails they leave on foliage. For information on controlling slugs, see HGIC 2357, Snails & Slugs in the Home Garden.

For more information on cabbage-eating caterpillars, see HGIC 2203, Cabbage, Broccoli & Other Cole Crop Insect Pests.

Karen Russ
Home & Garden Information Center

Page maintained by: Home & Garden Information Center

This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.