Watch for snail contamination in grain in NSW

Author: Ellen McNamara | Date: 16 Nov 2016

Garry McDonald says recent wet weather is likely to favour increased snail activity and spread.

Grain growers in southern New South Wales are encouraged to keep a close eye out for snail contamination of grain this harvest.

PestFacts south eastern coordinator Garry McDonald warns that while snails haven’t traditionally been a big issue for growers in NSW, there have been incidents of the pest in the past few years and recent wet weather is likely to favour increased activity and spread.

“It is worth growers being vigilant, because once you have snails in your paddock, they are very hard to get rid of,” Dr McDonald said.

“Without vigilance, we believe that there is a real risk that this pest will increase in southern NSW, as shown by snail colonisations in different locations of the Riverina and South West Slopes.

“This slow encroachment is a risk to growers, given snails are a problem at both ends of the crops life, causing potential contamination at harvest, and problems at crop emergence. Where there is even a hint of a problem, integrated management needs to occur across all seasons.”

The key points for NSW growers are:

  • Snail numbers can increase in seasons with wet springs, summers and autumns.
  • The only means to control juvenile snails (less than seven millimetres) is through the strategic use of burning.
  • A rule of thumb is if snail numbers are above 20 per square metre in cereals and 5/m2 in pulses and oilseeds, be prepared to deal with grain contamination at harvest.
  • Use header modifications and grain cleaning to eliminate snail contamination of grain.
  • The only natural predators of snails are ducks, including wood ducks
  • Snails appear to build up most rapidly in canola, field peas and beans. However, they can feed and multiply in all crops and pastures.
  • Baiting before egg laying is vital. Timing and choice of controls will depend on the season. Understand the factors that determine control effectiveness.
  • Stop baiting eight weeks before harvest to avoid bait contamination in grain.
  • Monitor snails regularly to establish numbers, types, activity and success of controls.
  • To control snails, you will need to apply a combination of treatments throughout the year.
  • Growers are reminded that the common white snail (Cernuella virgata) is a prohibited pest in important export markets, therefore it is vital that grain is delivered free of snails to maintain market access.

Dr McDonald said it’s important growers are proactive and remain vigilant about biosecurity, including adhering to hygiene measures and carefully managing the movement between farms of vehicles, machinery, pallets and other equipment.
“Snails are proficient hitchhikers, moving between regions on transport. Farm machinery and produce such as hay should be inspected and cleaned of snails before transport,” he said.

“By being aware of hygiene, and any numbers in crops, means NSW growers can work to reduce colonisation.”

The GRDC has published a Snail Management Fact Sheet which can be viewed and downloaded via this link. It provides information on minimising contamination at harvest as part of a year-round approach to controlling snails.

More information on harvest techniques and integrated snail management is contained in the GRDC publication Bash 'em, Burn 'em, Bait 'em which is available for viewing and download via this link

Contact Details 

For Interviews

Dr Garry McDonald, cesar 
03 9349 4723


Ellen McNamara, Cox Inall Communications
0429 897 129

Region North