{"id":14581,"date":"2026-05-20T00:44:22","date_gmt":"2026-05-20T00:44:22","guid":{"rendered":"https:\/\/www.europesays.com\/australia\/14581\/"},"modified":"2026-05-20T00:44:22","modified_gmt":"2026-05-20T00:44:22","slug":"will-double-strength-bait-stop-western-and-south-australias-mouse-plague","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/australia\/14581\/","title":{"rendered":"Will double-strength bait stop Western and South Australia’s mouse plague?"},"content":{"rendered":"

As people sleep in parts of Australia, mice are hidden in their beds biting their fingers, chewing machinery wiring and hoses, destroying grain crops, and rotting in streets.<\/p>\n

Some regions are in the grip of a mouse plague on a scale not seen since 2021.<\/p>\n

Millions of rodents have been wreaking havoc for months.<\/p>\n

And there’s no simple solution in sight.<\/p>\n

Here’s what you need to know about Australia’s mouse plague.<\/p>\n

Loading…Why is there a mouse plague?<\/p>\n

Mice began breeding extensively after the summer’s grain harvest in Western Australia.<\/p>\n

Agronomists and farmers in WA began raising the alarm in February, but even then, they were surprised at just how many rodents they were seeing.<\/p>\n

Mice can multiply quickly. They breed at six weeks old, can give birth to a litter of up to 10 offspring every 20 days, and can fall pregnant again as soon as they have given birth.<\/p>\n

\"A<\/p>\n

Some people are baiting and trapping hundreds of mice every day. (ABC Midwest and Wheatbelt: Chris Lewis)<\/p>\n

Conditions were perfect for vigorous breeding. There was plenty of food in paddocks after a record harvest<\/a> and fewer sheep to clean the spilt grain and stomp on their nests.<\/p>\n

And then some summer rain fell, providing mice with drinking water and milder temperatures.<\/p>\n

Where are the mice?<\/p>\n

Mice typically live everywhere humans do, but often in low numbers, so they’re not always seen.<\/p>\n

When they build to plague levels, there’s no escaping them.<\/p>\n

\"A<\/p>\n

Mice breed quickly, which is seeing numbers multiply. (Supplied: Deanne Flavel)<\/p>\n

Some towns in Western Australia, such as Northampton and Morawa, have mice infestations in their public buildings and homes. Surrounding farms are crawling with swarms of mice.<\/p>\n

Community leaders are worried the mice may lead to a disease outbreak, and the Department of Health has issued a public health alert, urging increased hygiene and care.<\/p>\n

\"A<\/p>\n

A map generated in March showing mouse distribution in Australia. (Supplied: CSIRO)<\/p>\n

Farmers in South Australia, Western Australia, and parts of northern NSW are seeing unusually high numbers of mice. Some estimates put the number at more than 8,000 mice per hectare.<\/p>\n

Citizen science website FeralScan shows reports of mice in every grain-growing state, from west of Brisbane to north of Sydney and close to the Adelaide CBD, along with extensive hotspots in WA.<\/p>\n

\"Peter<\/p>\n

Morawa grocery store owner Peter Thornton is fed up with the mouse problem plaguing his community. (ABC Midwest and Wheatbelt: Chris Lewis)<\/p>\n

Why is the standard bait not working?<\/p>\n

The standard bait farmers use contains 25 grams per kilogram of a toxin called zinc phosphide.<\/p>\n

To die from eating it, a mouse has to eat two or three grains of the poisoned wheat.<\/p>\n

In some paddocks, farmers are baiting, but there is a lot of food for the mouse to choose from, so it may only eat one poisoned grain.<\/p>\n

Eating one grain will make the mouse feel sick, but it won’t die, so farmers worry it may learn not to eat another poisoned grain.<\/p>\n

There are also so many mice that while the bait may remove half of a population, the remaining rodents just quickly breed and build up their numbers again.<\/p>\n

\"A<\/p>\n

Mouse bait spread on paddocks is wheat treated with poison. (ABC Mid West Wheatbelt: Chris Lewis)<\/p>\n

This week, the Australian Pesticides and Veterinary Medicines Authority issued an emergency permit <\/a>to allow some farmers to spread a double-strength bait on their paddocks.<\/p>\n

It is expected to bring mouse numbers down quickly because a mouse only has to eat one poisoned grain to die.<\/p>\n

What’s the environmental risk of the stronger farm bait?<\/p>\n

CSIRO mouse expert Steve Henry has been studying this.<\/p>\n

He says that zinc phosphide doesn’t bioaccumulate, with most of the toxin used up killing the mouse and the remaining amount dissipating into the environment.<\/p>\n

\"White<\/p>\n

Australia’s pest chemical regulator has approved permits for farmers to use double strength bait ZP50 to exterminate mice in their paddocks. (ABC Midwest and Wheatbelt: Jo Prendergast)<\/p>\n

So the chances of an animal eating poisoned mice and then getting sick are considered low.<\/p>\n

There is a risk that birds, such as parrots, may eat the poisoned grains in the paddocks, and there is a chance they can be poisoned.<\/p>\n

So far, the CSIRO research is not showing bird deaths as a concern, but there’s more work to be done in this space.<\/p>\n

The APVMA has imposed strict conditions on the emergency permit to help protect ‘non target species’.<\/p>\n

What damage are the mice doing?<\/p>\n

Grain farmers are busy planting this season’s grain crop, but some have described the mice vacuuming up the seeds once they’re in the ground.<\/p>\n

Crops that do start growing are also vulnerable to mice chewing them off.<\/p>\n

\"a<\/p>\n

Mouse holes dot along a line of seeded crop. Mice ate the seed before it could grow. (Supplied: Robert Mitchell)<\/p>\n

Some producers will have to re-seed their paddocks, a significant cost during a period of record-high fuel and fertiliser prices.<\/p>\n

Mice are also damaging cars and farm machinery, eating wiring and hoses.<\/p>\n

\"A<\/p>\n

Mice ate this radiator hose, causing the vehicle to lose its coolant.\u00a0 (Supplied: Alex Haeusler)<\/p>\n

They have spread from paddocks into towns, where food-based businesses like supermarkets are inundated. Some have thrown out tens of thousands of dollars’ worth of stock.<\/a><\/p>\n

And they’re taking a significant mental toll on people who have been trapping and baiting them for months.<\/p>\n

Some communities rely on income from wildflower tourism in winter. It is yet to be seen if travellers change their plans.<\/p>\n

How long will this plague last?<\/p>\n

Mouse plagues typically end due to a combination of factors, including food shortages, disease and cold weather.<\/p>\n

Once farmers spread the more effective baits on their paddocks, they should see a reduction in numbers within hours.<\/p>\n

But Mr Henry warns the bait can only be used on farms, not in urban areas, and while it will have an impact, it’s not a “silver bullet” for the problem.<\/p>\n

Mice may stop moving en masse out of the paddocks into houses and buildings, but they’ll still need to be removed from the areas they’re inhabiting now.<\/p>\n

Residents will need to keep trapping and baiting the vermin.<\/p>\n","protected":false},"excerpt":{"rendered":"As people sleep in parts of Australia, mice are hidden in their beds biting their fingers, chewing machinery…\n","protected":false},"author":2,"featured_media":14582,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[12165,22,21,14958,9689,3426,8735,8738,3425,464,14957,14956],"class_list":["post-14581","post","type-post","status-publish","format-standard","has-post-thumbnail","category-australia","tag-apvma","tag-au","tag-austrlia","tag-chemical-regulator","tag-csiro","tag-farmers","tag-mice","tag-mouse-bait","tag-mouse-plague","tag-wa-news","tag-wheatbelt","tag-zp50"],"_links":{"self":[{"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/posts\/14581","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/comments?post=14581"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/posts\/14581\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/media\/14582"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/media?parent=14581"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/categories?post=14581"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/australia\/wp-json\/wp\/v2\/tags?post=14581"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}