Miticide resistance in Varroa mites
What Victorian beekeepers need to know
Miticide resistance to pyrethroid and formamidine based chemical treatments has been found in Victoria, Queensland, New South Wales and South Australia.
In January 2026, the first case of Varroa mite (Varroa destructor) being resistant to pyrethroid-based treatments was found for the first time in Australia. This affects the use of the only two approved pyrethroid miticide treatments available in Australia:
- flumethrin (sold as Bayvarol)
- tau-fluvalinate (sold as Apistan).
This was discovered in a small number of apiaries in northern NSW after treatments were not working properly to reduce mite numbers. The NSW Department of Primary Industries and Regional Development (DPIRD) confirmed this.
In February 2026, the Queensland Department of Primary Industries (DPI) also confirmed this same resistance, known as L925I, in mites in south-east QLD. This case is linked to the earlier detection in NSW. After identifying these links, both states worked together to identify a second version of pyrethroid resistance called L925M, which is present in both NSW and QLD.
Another type of resistance, called formamidine resistance or Y215H (which affects the products Apivar and Apitraz), was also found in the northern NSW and south-east Queensland apiaries after treatment failures. In NSW, cases have now been confirmed in parts of the North Coast, Mid North Coast, Hunter and New England regions, and central NSW.
Also in May, South Australia confirmed resistance to both synthetic treatment groups in sentinel hives in the Pooginook Detection Zone, this finding was linked to NSW cases.
The affected chemical products are particularly important, as they make up four of the eight approved products currently available to control Varroa mites.
Miticide resistant mites in Victoria
On 13 May 2026, Agriculture Victoria confirmed that some Varroa mites in Victoria are resistant to pyrethroid-based treatments. This news came after reports that treatments were not working to control Varroa mite numbers as expected.
Genetic testing identified a mutation in these Varroa mites, L925I. This mutation significantly reduces how well pyrethroid treatments work in controlling resistant mite populations.
In early June, results from further testing confirmed the same mites are also resistant to formamidine based products (Apivar and Apitraz), as is the case with the resistant populations in other States. The presence of resistant mites in the Victorian apiary is not a result of individual actions, rather a product of broader circumstances in preceding months.
If this resistance spreads, beekeepers will lose some of their main tools for controlling Varroa mites. This could lead to more mites in hives and more bee colonies being lost. Resistance can spread through chemical misuse, the sale and movement of bees, and from nearby apiaries.
Proactive monitoring and observation are hallmarks of good beekeeping and reporting anything unusual is good for the entire industry.
Agriculture Victoria, NSW DPIRD and QLD DPI are working together to better understand how far miticide resistance has spread. Additional detections are expected in all states as testing continues.
State and territory governments, along with the Australian Government, are continuing to work with the beekeeping industry through the National Bee Biosecurity Program and the National Bee Pest Surveillance Program.
Miticide resistance
Miticide resistance happens when some Varroa mites naturally have small genetic differences that help them survive a chemical treatment that would normally kill them. Examples of this are the L925I and L925M mutations that can make Varroa resistant to pyrethroid treatments, and the Y215H mutation that can make Varroa resistant to formamidine treatments.
If the same chemical is used again and again, for too long or in the wrong way, the mites that survive will reproduce. These mites will pass that resistance to their offspring.
Over time, more mites in the population become resistant and the treatment becomes less effective – or may stop working completely.
What this means for beekeepers
Once Varroa mites develop resistance to a particular chemical treatment it may become less effective or no longer work at all.
If mites develop resistance to one or more chemical treatments, beekeepers lose important tools for controlling Varroa mite populations.
Fewer effective treatment options can make it harder and more expensive to manage Varroa mite in your apiary. It can lead to higher mite numbers in hives, more colony stress, and more colony losses.
Approved organic treatment options include Formic Pro, Aluen Cap, Api-Bioxal, and Apiguard.
Beekeepers should use integrated pest management (IPM), which means managing mites by using cultural, mechanical, and chemical options to control mite numbers and the damage that they cause.
You can learn more about these options and other management strategies at Integrated Pest Management — National Varroa Mite Management Program.
What is being done about miticide resistance
The NSW Government (DPIRD) is leading the response and working with Agriculture Victoria and QLD DPI to understand how resistance came about. A large tracing and testing program is in progress to understand where resistant Varroa mites are located and how far miticide resistance to treatments has spread.
Additional detections are expected as testing continues. Resistant mites have been detected in NSW in parts of the North Coast, Mid North Coast, Hunter and New England regions, and central NSW. In north east Victoria, and Queensland in Southern Downs, Ipswich, Logan, Brisbane, Redland Bay, Moreton Bay, Sunshine Coast, Paroo, and Bundaberg. Also in South Australia in sentinel hives in the Pooginook Detection Zone.
Genetic analysis completed by researchers at the NSW Elizabeth Macarthur Agricultural Institute (EMAI) has provided important insights. The viruses carried by the resistant mites indicate that this population represents a separate incursion of Varroa mite into Australia from the mites first detected in NSW in 2022.
This means that there has been a newer Varroa mite incursion into Australia, separate from mites first detected in 2022. These mites already had resistance-conferring genetic mutations. The pathway for the incursion is not known. So far, testing by the NSW Elizabeth Macarthur Agricultural Institute has shown there are no exotic (new) viruses in affected hives.
The Consultative Committee on Emergency Plant Pests considered this evidence at a national level and agreed that eradication of this resistant mite population is not technically feasible, because Varroa is so geographically widespread. As a result, eradication will not be attempted.
States, territories and the Australian Government continue to work with industry around Varroa mite, through the National Bee Biosecurity Program and National Bee Pest Surveillance Program.
What beekeepers should do
Beekeepers can protect their hives by following the Australian Honey Bee Industry Biosecurity Code of Practice.
To slow the development and spread of resistance, beekeepers should be correctly rotating miticides between chemical types, and using alternative mite control methods, not just chemicals. Keeping mite numbers below threshold levels will also help slow the spread.
Always check mite numbers before, during and after treatments to ensure that the chemical is needed, and that it is working, or whether further action is needed.
If resistance to miticide treatments has been found, these miticides can no longer be used. Continuing to use them will allow resistant mites to survive and increase, leading to colony loss.
To help with selection of appropriate chemicals, you can use the Varroa Management Tool.
Because fewer chemical treatments may work in the future, it is important to start using Integrated Pest Management (IPM) methods that do not rely solely on chemicals.
Where mite numbers are uncontrolled, there may be limited ability to save colonies. Early reporting of suspected resistance is critical, along with changing to a different chemical group of miticides if needed to control mite populations.
Combine monitoring, cultural/mechanical controls and use chemical treatments only when needed. Cultural controls include brood interruption for example by queen caging or splitting hives. Mechanical controls include using screened bottom boards with a sticky mat and removing drone brood.
Test your hives for mites regularly (monthly) using the alcohol wash method and apply chemical treatments only when treatment thresholds are met, instead of using a fixed schedule. Keep records of monitoring and any chemical treatments used.
In Australia, it is critical to only use chemicals that have been registered or granted an emergency permit by the Australian Pesticides and Veterinary Medicines Authority (APVMA) for the control of Varroa destructor. Using and importing unapproved ‘home brew’ or overseas products is illegal, and risks harming your bees, your own health, and can contaminate honey with residues.
Information on legal available chemical treatments can be found at Varroa chemical control options (National Varroa Mite Management Program)
Alternate between chemical treatments with different modes of action so mites are not repeatedly exposed to the same active ingredient.
Proper dosage and treatment duration are essential. Using miticides incorrectly can accelerate resistance in the Varroa population. Do not use less or more strips than the label advises or cut strips. Leave them in for as long as the label states. Do not remove early. If they are not working or are suspected to be not working – report the treatment failure immediately and wait for further advice.
By recording the product used, dates it was applied, and mite numbers before and after-treatment, beekeepers can tell when a treatment is no longer working. This can be a sign that there is potential build-up of resistance in the mite population in your apiary.
Stay up to date on the latest research and management practices to protect your hives from Varroa mite infestations and ensure the ongoing health of the colonies.
Report treatment failures
Don’t hesitate to report any suspected cases of treatment failure: contact the Exotic Plant Pest Hotline on 1800 084 881.
For more information
Beekeepers can access free resources on managing Varroa mites at National Varroa Mite Management Program
For Varroa management advice contact our Victorian Bee Biosecurity Officers on 136 186 or email honeybee.biosecurity@agriculture.vic.gov.au