Mid West farmers dealing with mouse plague report some initial improvement due to stronger baits, rains

Mid West farmers are making inroads in the battle against the region’s mouse plague, with help from winter rains and the approval to use a double-dose bait.

Last month, the Australian Pesticides and Veterinary Medicines Authority granted emergency permits for the sale and use of a stronger zinc phosphide bait, ZP-50 — a decision which many stakeholders claimed came too late.

Yandanooka grain farmer Jarrad Spencer said he had waited until seeding had begun late last week before baiting but had already seen an impact.

“We baited once seeding began four days ago — it took effect within a day,” he said.

Mr Spencer said he started baiting his 3500ha via spreader however, worried about worker exposure, invested in baiting via plane which incurred a significant cost.

To date, Mr Spencer said he had invested more than $68,000 into the process.

“Not that happy about the extra cost to an already expensive year,” he said.

Mr Spencer said he was confident ZP-50 would produce better results than the lesser dose as it had in previous years and was optimistic there would not be too much impact on harvest.

Agronomist and Yuna grower Belinda Eastough said she had seen a “significant drop off” in mice activity around Northhampton and Binnu due to early baiting with ZP-25.

“The 50g active came through a bit late for us, but anything that was baited earlier, before the mass numbers got extremely high, definitely the numbers have significantly dropped off,” she said.

Ms Eastough said she had still seen mouse activity and new holes however, believed most mice had hunkered down for the winter or had slowed their breeding cycle.

“I’m certainly not seeing the plethora of holes that we were seeing before,” she said.

Ms Eastough said there were exceptions, including a farm she visited last Thursday in Mingenew.

“We went to a paddock and that particular paddock was probably about 600ha and they’d lost around 400ha to mice, where the mice had eaten the canola seed out of the ground,” she said.

“And they had been baited however, the numbers were actually so high that there are lots and lots of new holes there.”

Ms Eastough said farmers needed to stay vigilant about monitoring.

Morawa shire president Karen Chappel said farmers dealing with the mice plague would only begin to see an improvement now, if any.

She said last week’s rain had caused crops to start coming out of the ground, allowing farmers to see the damage.

“What’s happening at the moment is farmers are assessing the damage and the need for rebaiting, and they’re out and they’re using 50g,” she said.

“Mice have reduced on the farms by a bit but the situation in the township is still not flash.”

Cr Chappel said the Morawa township no longer had mice carcasses on the streets, yet there were still significant numbers of mice being treated with household bait.

With numbers slightly decreasing on farms, she said it was important for farmers to keep an eye on their crops and the need to rebait.

Cameron Beeck, 4Farmers general manager, has been supplying the stronger baits to farmers after applying for a permit in February.

Demand was high until it ground to a halt at the start of last week, according to Mr Beeck.

He said he was not sure why orders had slowed, but wanted to ensure farmers knew who to call if they were searching for baits.

CSIRO research officer Steve Henry said now farmers had a control for the mice entering winter, he was hopeful the numbers would trend downwards.

“I’m hoping they’d be pushed to such low numbers in the wintertime that in the springtime it will take much longer for them to breed up to numbers that might cause damage to crops,” he said.

He said he was sure the stronger 50g poison could help some farmers get a “really good result”.

Mingenew farmer Fiona Cosgrove said Mingenew was having another “little boom” of mice right now.

Ms Cosgrove said she was currently still seeding and reseeding crops which had been eaten by mice, which did seem to slightly improve before getting worse again.

“We’re just now waiting for the rain to break to be able to spread the baits as we need a few solid days for the mice to digest it without it being washed away,” she said.

“On the other hand, we also need some really solid rain to start drowning them out. So, there’ a few things needing to happen before we can make it work and get it under control.”

Meanwhile, grain farmers are being urged to regularly check the mouse activity rating for their area before purchasing or applying ZP-50.

The warning came after Grain Producers Australia downgraded three regional areas in WA to low mouse activity levels, effectively blocking farmers in those regions from utilising the emergency permit put in place on May 15.

These areas include WA Central, WA Eastern and the WA Sandplain agro-ecological zones which covers parts of the Mid West and Great Southern.

“Eligibility can change as mouse activity levels change, so growers should review the latest classifications before purchasing or using ZP-50,” GPA research, development and extension spokesman Andrew Weidemann said.

The latest mouse activity classifications are updated every two weeks through the national mouse monitoring network, which can be accessed on the Grains Research and Development Corporation’s website.

Only zones classified as having moderate or high mouse activity are eligible for ZP-50.