Dealing with snails – the latest research findings

Take home messages

• When possible control snails prior to mating and egg-laying.
• Assess snail numbers when the snails are active.
• At best, a single bait application will achieve 70% snail control. It’s estimated that a level of 98% snail control is needed to significantly reduce next season’s snail population.
• If mice are present, bait mice before applying snail bait.

Background

The area affected by snails is growing and grain receival standards are tightening.

Snail time lapse cameras running continuously have significantly increased our understanding of snail behaviour.

Snail behaviour

• Snail movement is minimal in hot dry conditions.
• Snails move from one to four metres when there is sufficient moisture; as identified by change in the colour of the soil surface. (2 – 5 hours at 90% relative humidity in loam soils).
• The earliest snails can lay eggs is fourteen days after the snail becomes active and when the soil is wet to a depth of 30mm.
• Response to snail control treatments vary as a result of weather and paddock conditions and stage of the snail lifecycle.
• Snail numbers increase rapidly in wetter and extended seasons.
• Snail numbers tend to increase rapidly in canola and dense pulse crops.

Snail control

• Dislodgement of snails onto hot soil, during hot dry conditions reduces snail numbers if snails do not hydrate overnight. Repeat consecutive treatments increases mortality, especially in dense stubbles.
• Browning out paddocks over summer improves snail control.
• Metaldehyde baits degrade rapidly in temperatures above 35^oC.
• Snails encounter baits through random movement.
• Bait rates need to be increased for effective control in high snail populations.
• Baiting paddock perimeters assists with preventing reinvasion of paddocks.
• Count the number of live snails six days after treatment to assess mortality.

Delivering clean grain

Use of stripper fronts is the most effective way to reduce snails entering the harvester.

The most efficient way to reduce snail contamination in grain is to use snail crusher grain rollers.

Dual roller snail crusher grain roller machines can clean grain at a capacity of up to 50 tonnes per hour.

Conclusion

Knowledge, preparation and commitment are the king in controlling snails in the absence of a silver bullet.

Contact details

Michael Richards
PO Box 185 Stansbury SA 5582
0427 547 052
michael.yp@outlook.com
@michaelnrm
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