The Florida Department of Agriculture and Consumer Services says it has found about 1,000 of the snails, which can grow up to 10 inches long and 4 inches wide, within a 1-square-mile area, The Miami Herald reported Friday.
"It's us against the snails," Richard Gaskalla, the department's director of plant industry, said.
The snails of the species Achatina fulica are considered one of the most damaging land snails in the world, officials said, and will eat 500 different types of plants, lay about 1,200 eggs a year and can carry a strain of non-fatal meningitis.
Especially devastating to agricultural areas, the snails are only allowed into the United States under special permits for scientific research.
Florida has suffered invasions by the snail before.
In 1966, a boy visiting Hawaii brought back three to Miami where his grandmother turned them loose in her garden.
Soon, there were at least 18,000 of the snails in the area and it took authorities 10 years and $1 million to remove them, the Herald reported.