MIAMI – The giant African land snail, which can grow to the size of a fist and can carry a parasite that causes meningitis, was declared extirpated from South Florida last year after a decade of pest control.
They are baaack.
The dreaded snails — known to invasive species connoisseurs as GALS — were spotted by a gardener in June in Pasco County, north of Tampa, the first time a population of them has been detected outside of southern Florida.
To try to contain them, state officials quarantined a portion of Pasco County in the New Port Richey area this week. Plants, garden waste, waste, compost or building materials cannot legally be transported without permission for fear of spreading sticky molluscs. The quarantine extends from a radius of about half a mile from the identified snail population and can be changed or increased if more snails are found.
The return of the snails was a surprising and inappropriate development in a state where wildlife routinely makes headlines — a record 215-pound Burmese python was caught in the Everglades late last year — and where invasive species routinely wreak havoc. During a particularly rainy spring a few years ago, exterminators in Palm Beach County received numerous calls about Bufo toads, whose toxin is so poisonous they can kill dogs, that they were basking in swimming pools.
“Pasco County is a little drier than South Florida because you have this large area of scrub habitat,” said Bill Kern, a University of Florida associate professor who specializes in wildlife management. Giant African land snails typically “like wet and like dense vegetation.”
“Of course, they’ll be perfectly happy in irrigated areas, like nurseries or home landscapes,” he added.
Giant African land snails are “one of the most invasive pests on the planet,” according to the Florida Department of Agriculture and Consumer Services. They eat more than 500 types of plants, and they feed on stucco, “as a source of calcium”. They hide in cool, moist places during the day, feed at night, and lay thousands of eggs in their lifetime. Some snails can be eight inches long and five inches wide.
They can also carry a parasite that causes meningitis in humans and animals, the rat lungworm; for example, if people eat unwashed lettuce or other produce that snails have slipped through, leaving behind a trail of slime.
“DO NOT HANDLE SNAILS WITHOUT GLOVES!” the department of agriculture warned.
Dealing with invasive species that are destructive and not just nuisances can be very expensive, Dr. Kern said. Floridians spend $100 million a year fighting a single pest: the West Indian drywood termite.
On Wednesday, the state began treating the quarantine zone in Pasco County with a snail bait containing metaldehyde, a pesticide approved for use on vegetables and ornamentals that disrupts the digestive systems of and kills giant African land snails and other plants. .
Mellon, a rescue Labrador specially trained to detect giant African land snails, is “actively scouting” the area, according to the agriculture department, which owns several pest dogs. (They sit when they smell a snail.)
Florida has eradicated snails twice before: last year, after they appeared in Miami-Dade County in 2011, and in 1975, after they were first detected in the state in 1969. The Department of Agriculture reported in 2021 that a giant African land snail had it. It has not been found in Miami-Dade County since 2017, following an eradication effort that collected more than 168,000 snails.
The snails identified in Pasco County look different from those previously seen in Miami-Dade County: Their flesh is creamy white, rather than grayish brown.
The color leads state officials to suspect that the Pasco County snail population may have originated from a pet snail released into the wild. The creamy white flesh is “the most desirable feature for the illegal pet trade,” said Christina Chitty, director of public information for the Department of Agriculture’s plant industry division. It is illegal to import giant African land snails into the United States without a permit.
However, that is just a guess. “We won’t know how the Pasco County population came about,” Dr. Kern said.