Minimising harvest contamination by snails
If snail numbers remain above control threshold levels of 20/m2 in cereals and 5/m2 in pulses and canola then it is likely they may be present in harvested grain. This can occur if snail management practices early in the season were not applied or management of the snails was ineffective.
As the harvest season progresses snails migrate up the crop to escape the hot ground. Early in the harvest season snails are more likely to descend to the ground if there is a rain event rather than later in the season. If it is possible, harvest should be timed to coincide with cooler conditions.
Snails have been found to move into windrows (swaths) of crops that were windrowed green (for example, canola) and left to dry. However, windrowing cereals earlier and in cooler conditions may result in lower snail numbers.
Round snails (white Italian and vineyard snails) are more likely to be dislodged off crops during harvest. However, small pointed snails are often found in sheltered locations such as between the leaf and stem and are difficult to dislodge. These snails are more likely to be intact in the harvested grain.
Harvester modifications are more effective on round rather than conical snails. Cleaning grain after harvest may remove small pointed snails from the grain. For more information refer to Bash'em, Burn'em, Bait'em: Integrated snail management in crops and pastures, published by the South Australian Research and Development Institute.
Acknowledgements
Authored by Svetlana Micic, Entomologist, Department of Primary Industries and Regional Development (DPIRD); Ken Henry, South Australian Research and Development Institute (SARDI); Paul Horne, Entomologist, IPM Technologies, Victoria.
This work was produced with funding from the Grains Research and Development Corporation.
The following are gratefully acknowledged for their contributions:
Judy Bellati, SARDI; Peter Davis, DPIRD; Tony Dore, DPIRD; Dennis Hopkins, (retired) SARDI; Nathan Luke, SARDI; Stewart Learmonth, DPIRD; Peter Mangano, DPIRD; Phil Michael, (retired) DPIRD; Michael Nash; Marc Widmer, DPIRD.