Trials in Western Australia’s Great Southern Region have confirmed all active ingredients used in snail baits have equal efficacy in killing small pointed conical snails.
The 2016 ‘caged bait trials’ were conducted by the Stirlings to Coast Farmers (SCF) grower group in collaboration with the Western Australian Department of Agriculture and Food (DAFWA), as part of a project initiated by the Grains Research and Development Corporation (GRDC) Albany port zone Regional Cropping Solutions Network (RCSN).
“The amount of active ingredient per bait in the trials did not influence snail mortality,” SCF research officer Kathi McDonald said.
“However, the more bait points there were, the more snails were killed by the baits.
“There was no difference in the efficacy of rainfast baits compared with non-rainfast baits, but the trials suggested non-rainfast baits lost their integrity after 14 days.”
Dr McDonald said iron-based and metaldehyde-based baits caused similar snail mortalities in the trials.
“However, there is more product choice in the metaldehyde range which includes products starting at about $4 per hectare,” she said.
In 2017, SCF is conducting field trials which will further test the efficacy of best-bet baiting options in ‘real life’ paddock situations.
“Results so far suggest the field trials should use the highest registered rate of a bait that gives the most bait points per square metre – ideally at 48 bait points per square metre,” Dr McDonald said.
In addition to the snail research led by SCF, DAFWA researcher Svetlana Micic is leading another GRDC investment in WA as part of a national project led by the South Australian Research and Development Institute (SARDI).
This project aims to increase knowledge of damaging snail and slug species and provide grain growers with information to allow them to effectively and economically manage these pests through the use of cameras to monitor slug and snail movement.
Its end aim is to model when slugs and snails are active so baits can be targeted to control these mollusc pests.
The snail research coincides with a grower survey that has confirmed small pointed conical snails are an increasing problem in the Albany and Esperance port zones, particularly in canola and barley crops.
The survey was conducted by SCF as part of a project initiated by the GRDC Albany port zone RCSN group.
It was designed to help define the extent of the snail issue and identify current practices used in baiting control of snails and, to a lesser extent, slugs.
Dr McDonald said almost half the 120 growers who completed the survey indicated small pointed conical snails were present on their farms.
“Almost 60 per cent of growers with snails on their properties reported the pests were at levels requiring baiting,” she said.
“Most growers surveyed are just becoming aware of their snail problem, although some have recognised it as an issue for more than five years.
“Most growers with a snail issue apply baits at least once a year, usually after seeding with a spreader.
“However, there is a high level of uncertainty among growers as to the efficacy of baiting programs on small conical snail control.
“Baits were largely considered an effective control for slugs.”