Turf Magazine - February, 2012

SOUTH FEATURES

Giant Snails on the Move

By Ron Hall

These Giant African snails aren't just loathsome to look at. Measuring 8 inches long and more than 4 inches wide, they feed on 500 kinds of plants.
PHOTO BY DAVID G. ROBINSON, USDA APHIS PPQ, BUGWOOD.ORG

Ridding customers' properties of giant snails probably isn't something on the radar of most south Florida lawn care/pest control professionals. Not yet anyway. But, if these recently discovered invasive pests continue multiplying and expanding their range from Miami-Dade County, where they were discovered this past September, landscape pros will almost certainly be called to deal with them.

Besides being loathsome to look at, Giant African snails have indiscriminating appetites. They're 8 inches in length and more than 4 inches wide and they feed on 500 kinds of plants. The University of Florida IFAS Extension says they are "a serious threat" to Florida's agriculture, natural areas and landscapes. They can also cause damage to plaster and stucco structures and may carry a parasitic nematode that causes meningitis in humans.

They hide in plants and under debris, and come out at night to feed. Look for signs of feeding, or search for them out in the open on cloudy, rainy days or in damp, shady areas on sunny days.

Here are some tips to discourage them or eliminate them:

  • Eliminate mulches, ground cover and other dense vegetation that would provide them a moist, sheltering environment. This does go against the Florida-Friendly landscape recommendations, so UF IFAS recommends checking with the local country extension agent.
  • A board, saucer or unglazed flowerpot placed in a shady location can serve as a suitable refuge for snails where they can be hand-collected (wear gloves or use a utensil) and destroyed.
  • Reduce the amount of irrigation to deny snails the moist environment they prefer.
  • Newer mollusk baits contain iron phosphate as a toxicant. Iron phosphate is normally thought of as a fertilizer, but will also control snails. Iron phosphate baits are used in a variety of settings, such as lawns, gardens and non-crop areas, reports UF IFAS Extension.
  • Metaldhyde-containing baits, although effective for control, are not recommended because they're quite toxic to pets and wildlife.

If you're in the professional lawn care/pest control business it should go without saying that you must read and strictly obey label instructions on all chemical products that you use. But consider this a reminder nevertheless.