The Giant African Snail (G.A.S.), Lissachatina fulica, is one of the world’s most damaging invasive species. Originating in East Africa, this massive terrestrial gastropod has established itself globally in tropical and subtropical regions due to its prolific reproductive cycle. An adult snail can reach up to 8 inches in length and 5 inches in diameter. Its sheer size and voracious appetite allow it to cause widespread destruction, necessitating safe, effective, and legally compliant strategies for its eradication.
Identifying the Pest and Associated Risks
The Giant African Snail is easily distinguished by its conical shell, which is typically brownish with darker, nearly vertical stripes. A mature shell has seven to nine spirals and covers at least half of the snail’s body length. This mollusk poses two primary threats to invaded environments.
The first is widespread agricultural and environmental destruction, as the snail consumes over 500 different plant species. When vegetation is scarce, they consume non-traditional sources, including house stucco and paint, to obtain calcium. The second threat is the risk to human health because the snail can carry the parasitic nematode Angiostrongylus cantonensis, or rat lungworm. If transmitted to humans, this parasite causes eosinophilic meningitis, a potentially severe neurological condition.
Mandatory Reporting and Legal Compliance
A confirmed sighting of the Giant African Snail requires immediate action prioritizing regulatory compliance. The G.A.S. is classified as a federally quarantined pest under the United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) regulations. This classification makes it illegal to possess, transport, or sell the live snail without a federal permit, even if found on private property.
Upon identification, immediately contact your State Department of Agriculture or the USDA APHIS Plant Pest Hotline. These agencies must be notified to initiate an official, coordinated eradication program. Do not attempt to handle or dispose of the snail without guidance, as unauthorized control methods can inadvertently spread the infestation.
If officials direct you to handle the snail for identification or collection, wear disposable gloves at all times. This prevents direct contact with the snail’s slime trail or body, which could harbor the rat lungworm parasite. Authorities will then lead the control efforts, often establishing a quarantine zone and deploying specialized resources for safe containment and removal.
Physical and Chemical Eradication Methods
Physical Collection and Disposal
Direct removal combines physical collection with targeted chemical application. Physical methods begin with hand-picking, which is most effective at night or during overcast, moist weather when the snails are active. After collection, the snails must be destroyed using approved methods, such as freezing or immersion in a strong salt solution (often 25% brine) for a minimum of 48 hours.
Disposal of dead snails and eggs must follow official directions, typically involving double-bagging and burial or incineration to prevent further spread. Simple traps can supplement hand-picking, using items like inverted melon rinds or damp wooden boards placed in infested areas to attract the nocturnal snails. These traps must be checked daily to collect and destroy the pests.
Chemical Control
Chemical control relies on the strategic use of molluscicides, primarily those containing metaldehyde or iron phosphate. Metaldehyde acts rapidly by disrupting the snail’s central nervous system, causing excessive mucus secretion and dehydration. However, metaldehyde is toxic to non-target organisms, including pets and wildlife, and requires careful placement to minimize exposure risk.
Iron phosphate offers a safer alternative, often approved for organic production. This compound works as a stomach poison, causing the snail to cease feeding almost immediately after ingestion. Death is slower, typically taking three to six days. Both baits should be applied as pellets, scattered lightly in the evening around host plants and known hiding spots, avoiding clumps to maximize contact and reduce risk to other animals.
Long-Term Exclusion and Sanitation
Long-term exclusion and sanitation measures prevent re-establishment once the initial population is suppressed. A primary step is the removal of debris and clutter, as snails hide in dark, moist places like rock piles, overgrown weeds, and excessive mulch during the day. Reducing these sheltered areas minimizes the daytime refuge available.
Sanitation also involves eliminating attractive food sources, such as fallen fruit, decaying garden waste, and pet waste. Removing these materials reduces the incentive for pests to remain in the area. Habitat modification should include reducing dense ground cover to allow for increased sunlight and airflow, creating a drier environment less favorable to moisture-dependent snails.
Physical barriers can deter movement into garden beds or around valued plants. Copper strips or specialized fencing are effective because copper reacts with the snail’s slime, causing an unpleasant sensation that repels them. Maintaining a perimeter of bare soil or a coarse material like sand also discourages movement, as snails prefer smooth, moist surfaces for travel.