Snails can't take caffeine - Science Update - United States Pacific Basin Agricultural Research Center - Brief Article

Agricultural Research, May, 2003 by Robert G. Hollingsworth

For the first time, researchers have looked at caffeine as a possible control for slugs and snails--including the orchid snail, Zonitoides arboreus. This common, damaging pest likes to feed on the roots of Hawaii's colorful and exotic tropical orchids. Scientists discovered the effects of caffeine on mollusks by accident while using it to control a different pest of potted plants. They found that a 2-percent solution of caffeine sprayed onto the coconut husk-chip material--called coir--on which orchids were being grown killed nearly 95 percent of snails infesting the pots. In another trial, a 2-percent caffeine solution killed all but 5 snails infesting a group of orchid plants within 30 days of application, compared to' 35 snails left after a standard dose of a common molluscicide.

Caffeine is a naturally occurring compound in coffee and chocolate and is considered to be Generally Recognized As Safe by the Food and Drug Administration when used as a food additive to cola-type drinks. Future studies will show how well caffeine sprays may protect other floral crops from snail attack. Robert G. Hollingsworth, U.S. Pacific Basin Agricultural Research Center, Hilo, Hawaii; phone (808) 959-4349, e-mail rhollingsworth@pbarc.ars.usda.gov.