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Giant African snail

Alert

Have you seen Giant African snail?

Be on the lookout and report it.

Under Queensland legislation if you suspect the presence of Giant African snail, you must report it to Biosecurity Queensland on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

Early detection and reporting are key elements in controlling Giant African snail.

Giant African snail (Achatina fulica) is one of the world's largest and most damaging land snail pests. This snail is not currently in Australia. It is occasionally detected on imported shipping containers and materials.

It is commonly found under leaf litter, old roofing iron and timber, compost heaps, thickly grown ornamental shrubs and in crevices between rocks and tree roots. At night, they will often be found on fences, house walls and other barriers.

Scientific name

Achatina fulica

Cause

Giant African snail is a mollusc, otherwise known as Achatina fulica.

Description

Adults

  • Much larger than native Australian snails.
  • Shell ranges in size from 5–10cm, but can measure up to 30cm and weigh 1kg.
  • Shell is cone-shaped, tapering to a point as compared to many native snail species whose shells are mostly round-shaped.
  • Colour of the shell can vary, but is commonly brown with pale cream streaks.
  • Usually active at night, emerging at dusk to feed in the open then returning to shelter at dawn. They remain active during daylight on wet days.

Eggs

  • Eggs are laid in batches of 100–400.
  • Spherical to oval-shaped.
  • Approximately 5mm in diameter.
  • Cream to yellow in colour.

Juveniles

  • Similar to adults but not much bigger than the 5mm eggs they hatch from. They gradually grow to reach adult sizes.

Plant stage and plant parts affected

Giant African snails can feed on plants at any developmental stage. The snails can feed on leaves, shoots, fruit and bark.

Plant damage

The snails damage plants directly by feeding on leaves, shoots, fruit and bark. Due to their size, they can also cause structural damage as a result of the sheer weight of individual snails.

May be confused with

Giant African snails have a cone-shaped shell that tapers to a point, whereas many Australian snail species have round shells.

Distribution

From east Africa, giant African snails have spread to much of the Indo-Pacific region (bordering mainland and island areas of the Indian and Pacific Oceans) either accidentally or introduced as pets or as a food source.

An outbreak of these snails occurred in Gordonvale, Queensland, in 1977 and were eradicated. During this outbreak, snails were commonly found during the day at the base of banana clumps, particularly on neglected plants where there was a lot of leaf trash.

A lone giant African snail was found on a property in the Currumbin Valley in 2004. A baiting program and extensive surveillance in the surrounding area found no further giant African snails.

Hosts

Giant African snails usually feed on decomposing vegetation. When introduced to a new environment they will feed on a wide range of plants including cocoa, rubber, banana, papaw, citrus, sweet potato, cassava, most vegetables, legumes and ornamentals. They will also consume fallen fruit, garbage, human and animal excreta, and even the bodies and shells of other giant African snails.

They are polyphagous, so are able to eat over 500 plant species.

Impacts

If introduced to Australia, giant African snails have the potential to be serious environmental and agricultural pests, capable of feeding on over 500 species of plants - many which are of commercial importance.

How it is spread

Giant African snails are international hitchhiker pests. They can be carried on imported goods, shipping containers and crates, machinery and motor vehicles. They could also be introduced to Australia at the egg stage in soil or on plant material.

Monitoring and action

If you receive goods imported from overseas, examine them on arrival for giant African snail and other hitchhiker pests.

Examine new plant material and nursery stock, and keep a look out around crops and gardens for unusual levels of plant damage and snails with a cone shaped shell.

If detected, secure the snails so they do not escape and spread. Giant African snails can transmit disease if handled with bare hands. Wear gloves to collect individual snails or eggs and place them in a sealed container.

Report your detection immediately to Biosecurity Queensland immediately on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

Control

Giant African snails are difficult to eradicate. The eradication at Gordonvale followed an intensive 8 month program of snail collection, baiting and community education and engagement.

Legal requirements

Giant African snail is prohibited matter under the Biosecurity Act 2014.

Report suspected giant African snail to Biosecurity Queensland immediately on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

If you think you have found giant African snail, you must take all reasonable and practical steps under your control to minimise any associated risks. This is called a general biosecurity obligation (GBO).

Further information