A Fatal Java Jolt - using caffeine as a snail and slug repellent

National Wildlife, Oct-Nov, 2002

Rearching for a safe way to keep slugs and snails from munching your flowers and vegetables?

A little java may do the trick. Researchers with the U.S. Department of Agriculture in Hawaii report that caffeine not only repels slow-moving mollusks, but kills these pests at high concentrations.

The scientists dipped cabbage leaves in caffeine and found that slugs ate 64 percent less of these leaves than untreated cabbage. When sprayed with 2 percent caffeine solutions (about 20 times the strength of instant coffee), 92 percent of slugs and 95 percent of snails died. "The caffeine probably acts as a nerve poison," says Robert Hollingsworth, who led the study.

Slugs and snails do significant damage to crops worldwide, and are one of the most costly problems to Hawaii's ornamental flower industry, worth $60 million a year, Hollingsworth says. If approved for use as a pesticide by federal officials, caffeine could give farmers and homeowners a more palatable alternative to current mollusk repellents. Sounds like a boost to us.