Remove the caterpillar from the plant. Then look to see if there are any others around that you can hand pick. If you find more in a short time, it’s time to move from mechanical removal to chemical or biological warfare.
Pyrethrum is a concentrate of a natural plant pesticide produced by a plant in the chrysanthemum family. It is extremely effective against caterpillars and grubs. Spray it onto the plant and the critters will stop munching and die. Pyrethrum is not harmful to warm-blooded animals, but can harm cold-blooded animals such as reptiles and fish. (Maybe it would be effective on some of our politicians.) It should never be used near a stream or lake.
Pyrethrum remains effective for just a short time once it is used and it comes in organic formulations. It is used for a quick knock-down. Check instructions of the individual brand because there are different formulations. Most can be used fairly close to harvest.
Bacillus Thurengensis (BT) is a bacterium that causes a plague in many insects including grubs and caterpillars. It is specific to insects and completely harmless to anyone who isn’t one. There are several brands. Dipel is one of them. Once it is sprayed on the plants the insects ingest it. They get sick, stop feeding and die within a very short period of time. Upon the insect’s death, more bacillus is released, ready to infect once again.
Botanigard is one brand that contains a fungus which infects many insects and kills them. It is very effective but takes two to three days to work. It can be used with the pyrethrum. The pyrethrum will lower the population pressure immediately. The Botanigard stops future population explosions from occurring.
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