MIAMI — The giant African land snail, which can grow to the size of a fist and carry a parasite that causes meningitis, was declared eradicated from South Florida last year after a decade-long battle between humans and pests.
They are mad.
The dreaded snails – known to invasive species connoisseurs as GALS – were spotted in June by a gardener in Pasco County, north of Tampa, the first time a population of them was detected in outside of South Florida.
In an attempt to contain them, state officials placed part of Pasco County in the New Port Richey area under quarantine this week. No plants, yard waste, debris, compost or building material can legally be moved without permission, lest the sticky shellfish spread. The quarantine extends within a radius of approximately half a mile of the identified snail population and may change or expand if more snails are found.
The return of snails was a surprising and unwelcome development in a state where wildlife regularly makes headlines – a record-breaking 215-pound Burmese python was captured in the Everglades late last year – and where species invasive pests regularly wreak havoc. During a particularly rainy spring a few years ago, exterminators in Palm Beach County received a flurry of calls about Bufo toads, whose toxin is so toxic it can kill dogs, found to mate in swimming pools.
“Pasco County is a little drier than South Florida because you have this large area of brush habitat,” said Bill Kern, an associate professor at the University of Florida who specializes in wildlife management. harmful fauna. Giant African land snails “generally like humidity and they like dense vegetation”.
“Of course, in irrigated areas, like in nurseries or home landscapes, they will be perfectly happy,” 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 over 500 types of plants – and also feed on stucco, “as a source of calcium”. They hide in cool, moist places during the day, feed at night, and lay several thousand eggs during their lifetime. Some snails can reach eight inches long and five inches wide.
They can also carry a parasite, the rat lungworm, which causes meningitis in humans and animals – if, for example, people eat unwashed lettuce or other produce on which the carrier snail slipped, leaving behind a trail of slime.
“DO NOT HANDLE SNAILS WITHOUT WEARING GLOVES!” warns the Ministry of Agriculture.
Dealing with invasive species that are destructive and not just a nuisance can be very costly, Dr. Kern noted. Floridians spend about $100 million a year to control just one pest: the West Indian drywood termite.
On Wednesday, the state began treating the Pasco County quarantine area with a snail bait containing metaldehyde, a pesticide approved for use in vegetable and ornamental crops, fruit trees and other plants that disrupts the digestive system of giant African land snails and kills them. .
Mellon, a rescue Labrador specially trained to detect giant African land snails, has been “actively exploring” the area, according to the agriculture department, which has several pest-sniffing dogs. (They sit down when they smell a snail.)
Florida has eradicated snails twice before: last year, after they first appeared in Miami-Dade County in 2011, and in 1975, after they were first detected in the state in 1969. The Department of Agriculture announced in 2021 that a giant African land snail had not been found in Miami-Dade County since 2017, following an eradication effort in which more than 168,000 snails were collected.
The snails identified in Pasco County are different from those previously observed in Miami-Dade County: their flesh is creamy white rather than grayish brown.
The coloring makes state officials suspect that Pasco County’s snail population may have started from a pet snail released into the wild. The creamy white flesh “is the most desirable trait for the illegal pet trade,” said Christina Chitty, director of public information for the Department of Agriculture’s Plant Industry Division. Giant African land snails are illegal to import into the United States without a permit.
However, this is only an intuition. “We probably won’t know how the Pasco County population came about,” Dr. Kern said.