The detection of these snails provides an important reminder about the need for vigilance.
Where have they been reported?
An outbreak of the common white or vineyard snail (Cernuella virgata) has been confirmed in May from samples taken from native and volunteer grasses in a lane adjacent to a grain bunker near Lockhart in the NSW Riverina.
Fortunately, the snails do not appear to have yet spread on to the neighbouring properties and every effort is being made to prevent this occurring.
It is likely that the snails have been at the site for several years, breeding and slowly moving out.
An observant Local Government Noxious Weeds Officer, doing a routine laneway inspection, found the snails.
Riverina Local Land Services is working to support the grain handling authority and the Lockhart Shire Council to manage the pest, initially through burning of plant residues, baiting and on-site monitoring of the population. Baiting alone is not a strategy for eradication of the pest but can help to contain them. A public information session has already occurred.
Their arrival in the region could become a major concern if the snail pest was to spread. In South Australia, the common white snail is a significant problem both for its plant feeding damage, but more importantly as a contaminant of grains and pastures. It has also spread into Victoria, coming in from South Australia, and is present in Tasmania after arriving on a shipment of grain from South Australia about ten years ago.
About the common white snail white
Common white snails feed on organic matter that accumulates on the soil surface but will also feed on young crop plants.
They are considered a serious pest because they contaminate grain during harvest and can clog and damage harvest machinery.
The snails over-summer off the soil surface on stubble, posts and vegetation.
Most egg-laying occurs in autumn or early winter, although some laying continues to early spring.
For detailed information on common white snails, including their occurrence, lifecycle, behaviour, damage symptoms and management strategies, go to vineyard or common white snail within the new PestNote series.
At this time of year and in regions where snails are established, close monitoring for snail activity and correct timing of baiting before significant egg-laying occurs are critical steps to containing this pest.
Increased autumn rainfall, as in this year in the Riverina, is regarded as a good indicator of increased spring populations.
At the end of the season, cultural management of stubbles in January and February is an important control strategy.
In regions where common white snails are not established, we still recommend vigilance. Early identification of population growth is essential for rapid control. The importance of monitoring to determine feeding activity cannot be over emphasised. For further information on snail management refer to the GRDC Snail Management Fact Sheet.
Sources of field reports of common white snail
Lisa Castleman – Senior Land Services Officer & Cropping Agronomist, Riverina Local Land Services, Wagga Wagga (NSW Riverina)