Hygromiid snails
The Hygromiidae family includes invasive air-breathing land snails. These species are of concern to Australia:
- Monacha cartusiana – Carthusian snail, chartreuse snail
- Monacha cantiana – Kentish snail, Kentish garden snail
- Monacha syriaca – none reported.
Background
Species in the Hygromiidae family are considered pests of fodder crops and are a serious issue in Europe.
Monacha spp. have been intercepted in storerooms and containers of ships, on baggage and cargo, and in soil both with and without plants.
Impacts
Temperate terrestrial snails can damage and feed on native plants, horticultural and agricultural crops.
Monacha species exhibit a massing behaviour when populations reach high levels. This can disrupt agricultural operations, lowering crop yield and quality.
Identification
Carthusian snail
The Carthusian snail has a milky grey-white to yellowish-white shell, with bulbous whorls coiled to a flat cone. Near the aperture, the shell may be reddish or brown in colour.
Translucent brown bands can be visible, becoming paler towards the shell mouth. The umbilicus is narrow and partially covered by the shell lip.
Shell size is variable, from 6 to 18 mm.
Kentish snail
The Kentish snail has a creamy white to brownish red shell, which in juvenile specimens can be grown with hair on its upper side. The whorls are slightly convex, and the spire can be flattened or almost conical.
The aperture displays a whitish to reddish lip, which is less distinct than in Monacha cartusiana. The shell navel (umbilicus) is wide, taking about an eleventh to a seventh of the shell diameter.
Shell size is variable, from 10 to 20 mm.
The snail body is lightly coloured, with a reddish front and greyish brown tentacles.
The Kentish snail crawls slowly, it is easily irritated and secretes a colourless mucus.
Monacha syriaca
Monacha syriaca has a shell with characteristic white spiral bands below the suture, also visible in weathered shells.
The aperture has a prominent white lip visible from outside and the apertural margin is reddish or brown. The umbilicus is entirely closed.
Shell size is up to 13.5 mm.
The snail body is light yellowish with brown tentacles.
