Mice have started to cause problems in paddocks throughout the Esperance region.
While they're not at plague proportions yet, Esperance-based Precision Agronomics Australia agronomist Quenten Knight said hotspots had been detected at Salmon Gums and on the sand-gravel-type soils of the coastal plains.
He said despite the problem not being anywhere near as bad as it had been in previous years (namely 2012 when mice were in plague proportions), many growers were assessing how to tackle the situation before getting seriously stuck into their 2014/15 seeding programs this week.
He said given their experience in the past, growers had become a lot more vigilant with some having already started baiting programs.
Others would wait to bait behind their air seeders come seeding time.
"A lot of the mice activity is taking place in paddocks and regions where barley head loss was rife during the 2013/14 harvest," Mr Knight said.
"A significant percentage of barley crops in parts of the Esperance zone lost half a tonne to a tonne a hectare of seed last harvest.
"That's a fair seed source and with the lack of summer rain this year, that food source has remained on the ground."
Department of Agriculture and Food entomologist Svetlana Micic said baiting behind a seeding rig would prove to be effective if done correctly.
She said bare patches and chewed plants at plant establishment and white plant heads which were scattered or in patches during the spring (both in the vicinity of mouse holes) were a dead giveaway of further mouse activity.
She said the continual monitoring of plants was also imperative.
"Poor germination and chewed seeds or leaves of young plants is also evidence of mouse activity," Ms Micic said.
"Stems which have been gnawed just above the node causing the plant to die and seed which has been chewed in the head also means mice."
She said mice were always present in crops in low numbers but populations could increase rapidly if there was prolonged availability of high-quality feed, high crop yields and poor harvesting efficiency, early autumn rains which produce early seed-set of winter weeds, late spring or early summer rains which damage mature crops and produce a flush of summer weeds, favourable burrowing conditions such as cracking or light soils or heavy crop residues.
Ms Micic said in-crop baiting when damage occurred was the most obvious management strategy for the eradication of mice populations but minimising spilled grain or harvester grain loss in paddocks during the summer months was also an important tool.
"Heavy grazing can help clean up high harvest grain losses but sufficient ground cover should be left to minimise erosion potential," she said.
"Growers should clean up any concentrated spills of grain around field bins, augers and other grain storage and remove or reduce cover, including plant material, rubbish and general clutter around buildings, silos and fodder storage."
She said the purposeful control of weeds and volunteers along fence lines, crop margins and contour banks in autumn and before seed-set needed to be carried out to minimise sources of food and shelter for mice.
Ms Micic recommended sowing as evenly and as early as possible for each crop to achieve rapid establishment of strong plants, though warned against dry sowing.
"Slightly increased seeding rates and deep sowing are preferential if mouse numbers are elevated at seeding," she said.
"If possible, the cross-harrowing or rolling of a paddock after sowing would be beneficial to ensure good seed coverage and the removal of sowing lines."
South Australia continues to be the epicentre of an autumn mouse plague, with farmers continuing to report large numbers in many areas.
However, sowing continued with the official recommendation for farmers to bait for mice behind their air seeders rather than delay planting.
In June 2012 farmers throughout the Wheatbelt counted their losses after mice caused substantial crop damage over a number of weeks.
At the time experts couldn't pinpoint just one reason for the large mouse presence or put a monetary figure on how much crop had been lost up to that point but it was widely recognised as being a significant problem from Northampton to Esperance.
By the end of the month more than 100,000 hectares of WA farmland had already been treated, mainly in the Esperance and Geraldton port zones.
Source - http://www.farmweekly.com.au/
