Slug update

With conditions ripe for slug activity, rebaiting may be required under high infestations and recent rainfall in some areas.

Reports of high slug activity continue to rise in the medium to high rainfall zones of south-eastern Victoria and NSW, and within irrigated crops. High numbers have emerged in south west Victoria in areas that have received good April rainfall. Monitoring as part of a GRDC-funded project aimed at better understanding the biology of slugs indicates several species are active, including the black keeled slug (Milax gagates) and the striped field slug (Lehmannia nyctelia). Striped field slugs are considered less damaging to crop seedlings than other species. The number of slugs being detected under monitoring tiles has been well above thresholds for canola; isolated damage to seedlings has occurred where baiting was delayed, or all the bait was consumed due to the high slug densities and/or mice. 

A reminder that monitoring after bait application is required to ensure bait is still present to protect seedlings. Repeat baiting may be required depending on weather conditions and product choice. 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 slug baits see the GRDC update paper ‘New insights into slug and snail control’ and the ‘Snail and slug baiting guidelines’ developed by SARDI.

 

Sources of field reports

James Challis – Rodwells (Northern Country, VIC)

David Eksteen – Eksteen Consulting (North East, VIC)

Hamish Harrington – Gorst Rural (South West, VIC)

Michael Nash – Slug and snail researcher (Gippsland, VIC)

Greg Toomey – Landmark (Northern Country, VIC)