Bait snails now before they multiply
Researchers are encouraging grain growers across southern Australia to bait for snails with the onset of moist autumn conditions before the pests start reproducing.
Research suggests snails might be a significant problem in some areas this year as a result of above-average rain, high-yielding crops and subsequent large stubble load, in many parts of the southern cropping region in 2016.
Well-timed baiting is essential to ensure an effective kill while snails are feeding and before they start breeding and laying eggs.
South Australian Research and Development Institute researcher Helen Degraaf, with work supported by Grains Research and Development Corporation, said now was an opportune time to apply snail baits.
“The cool, damp evenings are activating the snails and there are fewer food sources available,” she said.
Ms Degraaf has been monitoring snail activity on South Australia’s Yorke Peninsula.
She said she had observed in the mornings both round and conical snails moving up from the ground and attaching to stubble and weeds and hunkering down to wait out the warm day before reactivating at night.
“We observed conical snails mating near Warooka, however no egg-laying was observed,” she said.
“Surface soil appeared too dry to support egg laying, but we would expect eggs to appear soon after the next fall of rain.”
Ms Degraaf reminded growers to be mindful mice could interfere with snail baiting and vice versa – snails also eat mouse bait. Each bait was only effective on the target pest.
“Dead snails, often in clusters, close to baits indicate that snail bait has reached its target.
“If bait is disappearing but no dead snails are evident, it’s likely that mice have taken the snail bait.”
Ms Degraaf said growers must ensure they applied a sufficient amount of snail bait.
“About 25 to 30 baits a square metre improves your control by increasing the chance a snail will encounter a bait, while also accounting for the high populations of hungry snails,” she said.
She said snails needed to feed and rehydrate before laying eggs. She said when snails were trying to lay eggs, they were less interested in eating the baits, so bait effectiveness was reduced.
Research by Ms Degraaf, undertaken as part of a new Grdcsupported project across the southern and western cropping regions, has found snail albumen glands, their reproductive organs, were increasing in size in late March and early April, which corresponded with higher moisture and dewier conditions.
More information on snail control is available on a GRDC snail management fact sheet online at www.grdc.com.au/grdcfs-snailmanagement and the GRDC snail identification and control back packet guide at www.grdc.com.au/bpg-snailidentificationandcontrol.