VARIABLE mice numbers are being reported by farmers across the state, with parts of the Adelaide Plains and Yorke Peninsula experiencing significant mice activity.
GRDC-funded CSIRO researcher Steve Henry, Canberra, said localised, heavy outbreaks in these areas was a concern.
"It is patchy, but after some of the good crops in those areas had wind damage in November last year, it meant a lot of grain was in the paddock and provided a food source for mice," he said.
"It is not widespread but a few farmers have reported a high number of active burrows but spotting mice has been difficult - so there are a lot of questions surrounding that.
"Compared to last season, numbers have increased because crops were sown in the absence of mice last year."
Mr Henry began a new trial on the Adelaide Plains this week and Mallala farmer Sam Irish had mice exclosures set on his property as a part of the trial.
The aim is to monitor emerging crop damage from mice directly after sowing, inside and outside of the exclosure.
Mr Irish said he had paddock mice activity earlier than usual this year, when compared with past seasons.
"It was during summer and that is not common," he said.
"We have been seeing mice during the day but not an abundance during the night, which is unusual to what happens in most seasons.
"There are definitely numbers out there and we will bait soon if they do not begin to steady off."
Other growers in the region had reported lower numbers, according to Salter Springs agronomist Craig Davis.
"That is not to say that mice are not around and farmers will not bait, but the risk is far lower across the broad area," he said.
"Holes have been dug out in paddocks though, so there are high numbers of burrows but relatively low mice numbers at this stage."
Numbers across the YP are "creeping up", and AW Vater & Co Kadina agronomist Zack Zweck said the region had greater mice activity in the past week than experienced across the past couple of seasons.
"They are not at plague proportions but it is a hassle and growers are baiting to try and keep the numbers down now, so populations do not spike at the end of the season and become an even bigger issue at seeding next year," he said.
"Some growers began baiting about a month ago after seeing a lot of burrows, but many began this week after seeing a fair bit of mice activity."
Minlaton mice bait supplier Scott Hoyle said the demand for bait had substantially increased.
"Last year, we did not manufacturer any bait because of low demand, but it spiked about a month ago," he said.
"It appears numbers are rising and significant burrow activity is being reported in pockets across the YP and in the Vic western Wimmera.
Across the Eyre Peninsula and parts of the South East, mice activity is so far low.
In the Upper SE, Cox Rural Keith's Scott Hutchings said mice numbers were minimal since the region was not impacted by a wet harvest last year.
"That is when the region will generally have mice activity but high stock numbers also take care of excess grain in paddocks from the season before too," he said.
"But heading toward Wolseley and closer to the Vic border, mice numbers have increased but so far it has not travelled to the Upper SE."
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