A full report of this study was published as:
G.F. Antonious, J.E. Meyer, J.A. Rogers and Y. Hu. 2007. Growing hot pepper for cabbage looper, Trichopulsia ni (Hubner) and spider mite, Tetranychus urticae (Koch) control. Journal of Environmental Science and Health Part B 42: 559–567. Download pdf.
Research is needed to provide alternative pesticides with minimal impact on human health and the environment. Farmers around the world have long used plant extracts to protect food and fiber from insects and mites. Peppers have shown particular promise as a source of botanical pesticides:
- Powdered chili pepper deters the onion fly, Delia antiqua, from laying eggs.
- A chemical from from hot peppers reduces growth of the spiny bollworm, Earias insulana and may repel cotton pests.
We conducted a study with four objectives:
- Identify hot peppers with high fruit quality and yield;
- Test the toxicity of hot pepper fruit extracts to larvae of the cabbage looper, Trichoplusia ni;
- Test the repellency of hot pepper fruit extracts to the two-spotted spider mite, Tetranychus urticae; and
- Identify the compounds in hot pepper extracts that kill or repel mites and insects.
Botanical pesticides were prepared in two ways:
- 20 g of ground dried pepper were shaken with 10 drops of detergent in 100 mL of water (approximately equal to 1.7 ounces of dried pepper per cup of water);
- 50 g of fresh pepper were blended in 100 mL of alcohol for 2 minutes (approximately equal to 4 ounces of fresh fruit per cup of alcohol).
Many of the hot peppers tested killed cabbage loopers. The most lethal was USDA accession PI 593566, a chili pepper available for sale here through Reimer Seeds.
Only one of the peppers tested repelled spider mites. It was USDA accession PI 241675, a tobasco chili from Ecuador. It is not available for sale, but it has also been reported to resist curly top virus of peppers, and might be incorporated into plant breeding programs to produce fruit with high concentration of pest control agents.