Exotic Pest Alert: Giant African snail
April 2015 Primefact 1394 1st edition
Plant Biosecurity and Product Integrity, Orange
Giant African snail (Achatina fulica) is an exotic
plant pest not established on Australia’s
mainland
This snail is a serious threat to Australia’s
environment
If found it must be reported promptly to the
Exotic Plant Pest Hotline 1800 084 881
Giant African snail
Giant African snail (GAS) is one of the world’s
largest and most damaging land snails.
Giant African snail prefers warm tropical
conditions. It can survive temperatures lower
than 2°C and higher than 30°C by becoming
dormant.
Sunshine will kill GAS so it is mostly active at
night time. During the day the snail burrows
underground or retreats into its shell.
Impacts
Giant African snail will eat over 500 different plant
species. Most damage is caused to vegetable
crops, flowers and other ornamentals.
Internationally there is interest in GAS as a meat
product and it is marketed in Europe and
America. However GAS meat has been reported
to transfer bacteria and parasites to humans if
raw or poorly cooked snail is consumed. Disease
transmission is also possible if snails are handled
with bare hands.
Giant African snail is a nuisance to humans when
large infestations occur due to the stench that
emanates from dead snails.
Decaying snail shells can alter soil properties
when calcium carbonate from shells neutralises
acid soils.
Figure 1 Giant African snail shells typically grow to
5–10 cm in length
Figure 2 Giant African snail shells can be reddish
brown with yellowish vertical stripes
Exotic Pest Alert: Giant African snail
2 NSW Department of Primary Industries, April 2015
Description
Giant African snail shells can grow to 12 cm
diameter and 20 cm length, although more
commonly 5–10 cm long.
The shell is conical, tapering to a point, with
7–9 whorls when fully grown.
Shell colouration is affected by environmental
conditions as well as genetic variability of the
source of the population. Shells are sometimes
described as light brown with dark brown stripes
while at other times described as reddish brown
with weak yellowish vertical markings.
Lifecycle
Giant African snail is hermaphroditic. Both
partners of a mating pair will produce offspring as
they can simultaneously fertilise each other.
Lifespan is generally 3–5 years but periods of
hibernation can prolong life up to 9 years.
Sexually mature after 6 months, GAS can lay
over 1000 eggs in a lifetime. In ideal conditions,
eggs will hatch 11 days after being laid.
Host range
Giant African snail will feed on a broad range of
host plants. Hatchlings will mostly eat sand and
rocks for shell formation. Older snails prefer to
feed on vegetation including crop plants such as
cocoa, banana, beans, brassicas, cucurbits,
peas, beans, and ornamental plants.
Spread
Highly adaptive to a wide range of conditions,
giant African snail will modify its lifecycle to suit
the local environment.
Although GAS can move up to 50 m overnight,
on average it will not move more than 250 m in
one year.
Trade and transport are the main mechanisms of
human assisted long distance dispersal. Giant
African snail has been found attached to shipping
containers and machinery. Eggs have been
found in soil associated with imported goods.
Distribution
Giant African snail is native to coastal east Africa
but is now found across Asia, the Pacific, the
Americas and Europe.
Giant African snail occurs in coastal and native
environments, agricultural crops and plantations,
urban areas and scrub.
Within Australia, GAS has established on
Christmas Island but is kept at low population
levels due to predation by native red crabs.
On the mainland GAS has been intercepted and
destroyed at port facilities.
Actions to minimise risks
Put in place biosecurity best practice actions to
prevent entry, establishment and spread of pests
and diseases:
practice “Come clean, Go clean”
ensure all staff and visitors are instructed
in and adhere to your business
management hygiene requirements
keep records
Reporting
If you suspect giant African snail:
Call the Exotic Plant Pest Hotline on
1800 084 881
Take photos not samples to minimise the
risk of spreading this pest
Email clear photos with a brief
explanation and contact details to
biosecurity@dpi.nsw.gov.au
An exotic plant pest is a disease causing
organism or an invertebrate not present in
Australia and which threatens agricultural
production, forestry or native and amenity plants.
Acknowledgments
Figure 1 courtesy of Andrew Derksen, FDACS/DPI,
Bugwood.org
Figure 2 courtesy of David G. Robinson, USDA APHIS PPQ,
Bugwood.org
© State of New South Wales through the Department of Trade and
Investment, Regional Infrastructure and Services 2015. You may copy,
distribute and otherwise freely deal with this publication for any
purpose, provided that you attribute the NSW Department of Primary
Industries as the owner.
Disclaimer: The information contained in this publication is based on
knowledge and understanding at the time of writing (April 2015).
However, because of advances in knowledge, users are reminded of
the need to ensure that information upon which they rely is up to date
and to check currency of the information with the appropriate officer of
the Department of Primary Industries or the user’s independent
adviser.
Published by the NSW Department of Primary Industries.
PUB15/140
mailto:biosecurity@dpi.nsw.gov.au
