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Post-sowing snail considerations

Good snail management requires population reduction at every opportunity.

Snails are notorious for building up in large numbers, and appear to be an increasing problem in many parts of south-eastern Australia. Best practice management for these pests involves an integrated approach including burning, rolling, cabling and baiting before egg laying in autumn. Although the window of opportunity for these control methods is well and truly behind us this season, high populations may still require ongoing vigilance and baiting to alleviate the burden. Snails will not only feed on emerging seedlings in autumn and winter, but present a contamination risk at harvest. If snails are building up in your paddocks, here are some points to consider.

Snail size

Baits are more effective at controlling adult snails. While it is not entirely understood why this is the case, it may be due to the increased likelihood of the larger snails (> 7 mm) encountering baits. If populations of juveniles are high (e.g. a recent report received from the Victorian Mallee revealed up to 1000 juvenile vineyard snails/m2 in places), a higher baiting rate may increase the likelihood of these smaller snails encountering baits.

High number of vineyard snails (aka common white snail) have been reported in the Victorian Mallee (Source: SARDI).

 

Alternative food sources

Part of the reason why baiting is more efficacious prior to sowing is the absence of alternative food sources for snails to encounter. With crops taking off, there will be more alternative feed as the season progresses so avoid further delays if baiting is required.

Bait stability

If baiting is required, be aware that some baits are far more stable than others under adverse weather conditions, such as cold temperatures and significant rainfall. Rainfall (> 35 mm) erodes bran-based baits rapidly and reduces efficacy, with these products requiring re-application even after one week in wet conditions. For more information on snail and slug baits see the GRDC update paper ‘New insights into slug and snail control’ and the ‘Snail and slug baiting guidelines’ developed by SARDI.

To learn more about the common snail pest species found in broadacre crops and pastures visit vineyard snail (Cernuella virgata), white Italian snail (Theba pisana), small pointed snail (Prietocella barbara), and pointed snail (Cochlicella acuta) within our PestNote series. 

 

Field reports

Brett Akin – Elders (Mallee, VIC)

Shaun Krahnert – Elders (Mallee, VIC)

Rob Launder – PB seeds (Wimmera, VIC)

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