Control With Bt

Bt (Bacillus thuringiensis) is a bacterial insecticide. It kills most leaf-eating caterpillars. It comes as a dust or a liquid spray. BT controls tomato hornworms, cabbage worms, loopers, cankerworms and other insects that pass through a caterpillar stage, as well as tree-infesting crawlers like gypsy moths and tent caterpillars. BT must be eaten by the caterpillars to be effective, all parts of the leaves - especially, the undersides - should be thoroughly covered. Spraying the bottom half of leaves also keeps the viable spores more active because they survive longer when not hit by direct sunlight. Always apply Bt according to the instructions on the package. If the caterpillars are not all gone in three or four days try another application.

For more details and some good tips about using Bt effectively, see the file Using Bt Insecticide

For more information aboutr available Bt products see go to Yardener's Tool Shed and check out the file Bacillus thuriengensis.

If you need a sprayer, go to Hand Tools For Spraying in Yardener's Tool Shed.

Other Natural Insecticides

There are a number of effective natural insecticides made from materials such as chrysanthemum blossoms (pyrethrum) or neem oil soap. There is detailed information about these natural insecticides in Yardener’s Tool Shed. Go to the file called Natural Insecticides.

Repel Caterpillars

There are several natural insecticides that often kill caterpillars on contact, but then will create a bad taste for the caterpillar and make it go someplace else to munch. Neem Oil Soap, Hot Pepper Wax, and Garlic Barrier all have this potential repellent capability when applied properly on the tops and the bottoms of leaves of the target plant. The repelling effect will last for several weeks to a month depending on the weather conditions.

See the Natural Repellents in Yardener's Tool Shed.