Snails up despite dry

Snail numbers have boomed across most agricultural areas of SA in recent years, driven in part by wet summers.

SARDI research scientist Greg Baker said work was being done to get a clearer picture of the density of the different snail species around the State.

"We don't have a clear picture at the moment of how high snail numbers are, but the impression I get is that although it's been drier over the last six months, numbers are still quite high and there's still a reasonable density of snails in those at-risk districts," he said.

Several heat waves in January caused some mortality of round snails, but conical snails were better protected under refuges and survived.

SARDI scientists were surveying snail species on Eyre Peninsula and SARDI research into snails was supported by the GRDC.

"As part of our GRDC-funded work, one of our briefs is to survey areas of the State and get a clearer picture of the distribution of the different snail species and correlate the environmental factors of soil type and rainfall," he said

Mr Baker said that summer rains could stimulate snail activity, and if the resultant soil moisture was sufficient, it may present an opportunity for strategic baiting.

"But, one of the issues with baiting in the summer months is sunlight (UV) breaking down the active ingredient in the bait," he said.

"Research measuring the loss of bait efficacy under summer conditions is underway, and will be used to make new bait timing recommendations."

To tackle 'bash 'em' strategies for snail control, such as rolling or cabling, temperatures really needed to be 35 degrees and above.

"However, although snail kill rates are increased, the risk of starting fire from cabling operations increases as temperatures rise above 35 degrees," Mr Baker said.

"Unfortunately, this limits the occasions that growers can safely conduct these control practices."

*Full report in Stock Journal, February 7 issue, 2013.