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Basel, 01 May 2003

Some curious & unconventional usages of citric acid

Basel, Mai 1st, 2003 – Citric acid recently has emerged as a promising tool to control noisy coqui frogs in Hawaii, according to the U.S. Department of Agriculture (USDA).

The coqui frog, native to Puerto Rico, is known for its loud nighttime chirping. The noise from a group of frogs can exceed 90 decibels (which equals the intensity of a lawnmower). Likely transported to Hawaii on imported plant material in 1988, the coqui frog can now be found on the Hawaiian islands where frog populations are firmly established in numerous locations. The coqui with its voracious appetite is a threat to the islands' fragile native eco systems.

The first major test of citric acid is underway at Lava Tree State Monument near Pohoiki. The dime-sized coqui are nocturnal and typically hide in soil, palm leaves and bromeliads during the day. A 16% citric acid solution is sprayed in the evening to prevent their spread.

The citric acid solution sprayed on plants has not shown to cause any damage to plants if washed off within two hours.

Caffeine has also been found to be effective against these frogs. However, the USDA scientists who are continually searching for more economical methods to selectively target this invasive species without impacting other species or residents, say that citric acid, so far, is considerably safer than the caffeine.