A breed of giant, ravenous snails that first appeared in Barbados five years ago has thrived on the tropical island, destroying crops and prompting calls for the government to eliminate the slimy pests.

A nocturnal "snail hunt" last weekend reported finding hundreds of thousands of giant African snails swarming the central parish of St. George, the country's agricultural heartland, where farmers had complained of damage to crops including sugar cane, bananas and papayas.

"We saw snails riding on each other's backs and moving in clusters," said David Walrond, chairman of the local emergency response office, which organized 60 volunteers for the hunt. "You're just crunching the shells as you're walking through."

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The volunteers sprayed government-supplied pesticides in gullies and other cool, low-lying areas where the snails are believed to breed, venturing out after dark to catch the snails as they emerge from spending the day underground.

Walrond's brigade plans to continue its assault over the next three weekends.

The snails, which are about the size of a human hand, are known to consume as many as 500 different plants and their mucous can transmit meningitis and other diseases.