Giant African snail

An exotic pest – not wanted in Australia

The Giant African snail (Lissachatina fulica) is one of the world’s largest and most damaging snails that feeds on over 500 plants species and would threaten our vegetable crops, flowers and other ornamental industries. Keeping it out of the country is a national priority.

Have you seen this pest?

What should I do?

• Report it immediately.
• Share your photos with us using the online public reporting form.
• Call the Exotic Plant Pest Hotline 1800 084 881.
• Please take good-quality photos of the pest and/or damage to include in your report. For tips, see our guide to taking good photos.

Why is it a pest of concern?

The exotic giant African snail (Figure 1) causes serious economic and environmental impacts. It is known to feed on over 500 species of plants, causing serious biodiversity loss within its native and introduced ranges.

It poses significant health risk to humans and animals by carrying rat lung worm, a parasite that can cause meningitis. It can spread bacteria and fungal and parasitic pathogens that impact plants and humans. Do not pick these snails up without wearing gloves.

Pest profile

Appearance

• Adults: Large shells are usually between 50mm and 100 mm long, but can be up to 200 mm, weighing up to 1 kg. The shell is long and conical shaped, half as wide as long, generally light brown with alternating brown and cream bands and faint yellowish vertical markings on the upper ridges or whorls. Diet and environment influence shell colour variations. All fully grown snails have 7 to 9 whorls on their shells (Figures 1 and 2).
• Immature (juveniles): Smaller versions of the adult and do not have all whorls developed.
• Eggs: Spherical to oval shaped and measure 4.5 mm to 5.5 mm in diameter. Their colour ranges from cream to yellow (Figure 3).

Identifying signs

• Where to look: Egg masses may be found on imported produce and any cargo from shipping containers or crates.
• Distinct features: Snails will leave large snail trails and will cause unusually high levels of damaged plant material within agricultural crops, fruit and vegetables, native and ornamental plants, forests, and non-agricultural environments.

Host plants in Australia

Many important crops are hosts of the giant African snail, including banana, bean, breadfruit, cabbage, cacao, carrot, cauliflower, cassava, cotton, cucumber, eggplant, marigold, melons, noni, okra, papaya, peas, pumpkin, sponge gourd, taro and ornamental plants.

Life cycle

The snail is hermaphroditic, so both adult snails in the mating pair can lay egg masses of between 100 and 400 eggs on host plants. These will hatch after 11 days in ideal conditions. Average lifespan is 3 to 5 years.

Distribution and dispersal

• Originally from the east coast of Africa, it has now spread to south and south-east Asia, Oceania, the USA and Canada.
• Giant African snails can hitchhike in shipping containers, crates, machinery, motor vehicles and imported plant material or in soil, including as eggs. Illegal importation in the pet trade may be an issue.

Prevention

Monitor imported cargo and host plants carefully to prevent the introduction of the pest.

Image credits

• Figure 1: Giant African snail adult. Andrew Derksen, USDA-APHIS, Bugwood.org (CC BY-NC 3.0 US).
• Figure 2: Giant African snails on papaya. Scot Nelson Flickr 2011 Public Domain (CC0 1.0).
• Figure 3: Giant African snail eggs at the base of a papaya stem. Scot Nelson Flickr 2011 Public Domain (CC0 1.0).