May Pest of the Month: Green snail

Monday, 4 May 2020

Name: Green snail – Cantereus apertus

Green snail was first detected in the south-western coastal area of Western Australia in the 1980s. Its distribution in Western Australia is relatively restricted. In 2011 green snail was detected near Cobram in the north of Victoria for the first time. A restricted area has been declared around the infestation.

Green snail can significantly damage a wide range of host plants and is regarded as a serious pest. It has the potential to cause crop losses in cabbages, cauliflowers, lettuces, peas, beans, wheat, lupins, pasture grasses and native plants.


Green snails have an olive-green to light brown shell without any banding, and are approximately 15–25mm in diameter. The body is light creamy yellow and up to 55mm when extended.

Green snails do not appear to be restricted to any particular soil or vegetation type. They tend to be ground dwelling and thrive in open grasslands. They can also inhabit areas of natural bush.

In Western Australia during the dry summer months (November–March), the snails burrow underground and lie in a dormant state. Following autumn and winter rains the snails become active, with eggs laid in the soil from May–August and young snails appearing in early winter. The snail can breed very quickly, resulting in up to 1000 young snails per square metre.


The damage caused by green snail is similar to that of common garden snail – feeding on the surfaces of young leaves, often only penetrating shallowly and leaving a ‘windowpane’ effect. Older snails eat holes in the leaves and may reduce them to veins only. During summer (December – March), green snails lie dormant below the soil surface and do not pose a risk.

For further information please refer to the Pest ID Tool at:

Note that the Pest ID tool is now available with free access to industry.

An initiative of the Nursery Levy funded National Nursery Industry Biosecurity Program (NY15004) and ‘Building the resilience and on-farm biosecurity capacity of the Australian production nursery industry’ Project (NY15002).