Expert tips on major mouse plague

TOMORROW the Grains Research and Development Corporation (GRDC) is live streaming a special online seminar updating farmers on the escalating mouse plague and its potential threat to the 2021 winter grain crop.

GRDC experts will be accompanied by Steve Henry, lead mouse researcher from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and will be providing information on mice impacts, effective mouse control and the latest bait research.

See webinar details below

Mr Henry said the first thing residents should do to keep mice out of their house, is to pack steel wool int0 any holes where mice could gain inside access.

“Go down to the local hardware store and get a big bunch of steel wool, everywhere there’s a tiny opening, crack or pipe in the walls or roof spaces, shove steel wool into those cracks to stop mice coming in, because they won’t eat steel wool,” said Mr Henry.

“Clean up around the garden, piles of sticks and stuff, anywhere where mice could shelter and clean up food sources like left over pet food in bowls, bird avaries and chicken runs,” he said.

“The next step is using commercially supplied baits, which I believe is in short supply and use them according to the labels,” he said.

“The other way to do it is use snap traps, which takes away the need for chemicals.”

The mice plague has arrived because of an increase in food, shelter and moisture, mainly due to the improved seasonal conditions experienced in 2020. 

“One of the reasons why we are where we’re at now is last year we had good conditions coupled with what we would describe as a mild winter with a high level of mice survival, so mice started to breed earlier in spring and they can breed at six weeks of age, producing a litter every 19 to 21 days after that,” explained Mr Henry.

“Mice can live quite successful in free water but they don’t breed successfully, but what we’ve had is favourable conditions and we start to introduce food into the system and then they start to breed early,” he said.

“Mice are present everywhere all of the time  and when conditions are not favourable they are present but in almost undetectable levels.

“Rather than thinking of wave of mice moving across the landscape, it’s rather a whole lot of isolated populations that are getting bigger and bigger.

“If they’ve got food and shelter they’re not moving,” said Mr Henry.

Mr Henry stressed the importance of disposing of dead mice when baiting and trapping, in order to prevent the spread of disease.

“If using bait outside, get out and wonder around and pick up and dispose of any carcasses laying about because second hand poisoning is a real issue with other animals in urban settings,” said Mr Henry.

“The whole idea of cats controlling mice outbreaks are just nonsense, because a cat takes one or two mice a day and mice breed so quickly there’s no way cats can take enough mice to reduce it,” he said.

“Farmers use zinc phosphide to control mice, which is different to the chemicals they use to poisons mice around houses and the mode of action is different.

“Once the mouse is dead there’s almost zero phosphide left in it to poison another animal that comes along and picks up the mouse, so that’s different to the other ranges of toxins that are use on mice around towns, it’s extremely important to pick up dead ones there.

“I know bucket traps are effective but drowning is not a nice way to kill things and even though these critters are an introduced pest, they still require the same respect level as a kangaroo or cat or koala,” Mr Henry said.

Unfortunately it is near impossible to predict the end of the current plague however, Mr Henry said if the community bands together the mice have less chance of survival.

“The spread of disease coupled with lower food levels and mice resorting to cannibalism is what usually makes the population plummet,” said Mr Henry.

‘”If the food for mice holds out into the autumn, then they’ll continue to breed and cause problems into the winter crop season in May,” he said.

“If farmers can get together and all apply bait about the same time on as broad of scale as possible, they have the best chance of getting control and to get the best value for their bait application, they should be laying their bait when the food source in the paddocks are at the lowest level, giving the mice the best chance to discover the toxin.

“Farmers should also report and map mouse activity, both presence and absence, using MouseAlert Twitter using @MouseAlert so other growers can see what activity is being observed in their neighbourhood.

“It sounds ridiculous but the big hope is they go to astronomical numbers quickly and then crash,” Mr Henry said.

Those who wish to attend the online seminar must register however, it will be recorded and available for viewing and downloading via the GRDC website.

More details about mouse control options are available via the GRDC Mouse Control website.

Webinar discussion topics:

• Critical mouse control considerations ahead of the summer crop harvest and in the lead up to autumn sowing of winter crops;
• Maximising the effectiveness of control using zinc phosphide;
• The latest research on baits;
• Monitoring, including the development of remote systems;
• Ecology – the impact of farming systems on mice. 

Webinar details:

When: Friday, February 12 beginning at 9am AEDT (8am Queensland, 8:30am SA and 6am WA);

Where: Online via the GRDC website, register here;

Cost: Free.