Giant African Snail

Giant African snail (GAS) refers to several snail species from East Africa. One species, Lissachatina fulica, can grow almost eight inches long. This species has a long, conical shell which usually consists of 7–9 whorls. The largest whorl can measure five inches in diameter which is about the size of an average adult’s fist. Shell color can vary depending on the snail’s diet but usually consists of brown and tan stripes with variations of light brown and cream. Often the tip of the shell is lighter or white.

GAS are very prolific and just two snails can produce an infestation in a relatively short time. Each snail contains both male and female reproductive organs and can produce up to 1200 eggs/year.

Adult snails are typically nocturnal—feeding at night and seeking shelter during the day time. They become more active during damp or humid weather. Juvenile snails may feed during the day. In heavy infestations, snails will be visible in the open, any time of day and are considered a nuisance.

Immature snails are smaller and may resemble some native snails. It is best to contact an expert if you suspect a large snail could be a giant African snail.

Impact: 

GAS are frequently intercepted despite being illegal to buy, trade or sell in the United States. These snails move around the world readily for many uses—pet trade, culinary, education and medicine. They feed on over 500 plants including many important agriculture crops. Additionally, GAS can be an intermediate host that vectors several parasites—one of which causes a rare form of meningitis in humans.

In the late 1960s a boy returning from vacation smuggled three giant African snails from Hawaii to Florida. His grandmother soon released them into her garden. About three years later state and federal agencies were alerted and a survey and eradication program was launched. More than 18,000 snails were destroyed at a cost of $1 million. Recently a population of GAS was identified in Florida and over 157,000 snails have been collected and destroyed to date.

Pathways: 

Giant African snails are known as the traveling species because they move readily around the world. They have been seized from cargo labeled for sale as pets, for food and for education and medicinal purposes.

Additionally, all life stages can be introduced unknowingly as hitchhikers on imported cargo.

Hosts: 

The giant African snail feeds on a wide variety of plants including many agricultural crops of economic importance, native and landscape plants. Over 500 hosts plants have been documented and new hosts could be utilized in new environments. These species feed on the bark of larger trees and on cement, stucco and paint to assist in hardening their shells.

Detection: 

Giant African snail is native to tropical and subtropical regions however much of the US could provide an environment suitable for their establishment. The following characteristics apply to Lissachatina fulica:

  • adult snails may reach eight inches in length but commonly are 2–4 inches
  • diameter of shell reaches five inches at its widest point
  • shell is long and conical and consists of 7–9 whorls
  • shell color is variable—typically reddish brown with alternating light brown, tan or cream bands
  • body can be mottled brown or light cream
  • two pairs of tentacles on the head

 

Think you've spotted this pest?

If you think you've found this pest in your landscape contact your local extension office to see about sending in a sample.
Find your local extension office here.