No. 100 - Winter 2026

Concentrated mouse bait approved for producers

A concentrated mouse bait containing 50 grams per kilogram of zinc phosphide (ZP50) has been approved under an emergency permit.  ZP50 will give farmers an additional tool to manage severe mouse populations and support better crop protection.

National permit supports coordinated response

The Australian Pesticides and Veterinary Medicines Authority issued an emergency permit for the use of ZP50.

Grain producers will have ongoing access to 25 g/kg zinc phosphide (ZP25) mouse bait, and the permit allows the use of double strength bait to tackle severe mouse activity. A national monitoring network helps farmers decide when ZP50 is used.

To access ZP50, farmers need to:

• complete a free online stewardship training course through Grain Producers Australia (GPA)
• be located in regions meeting mouse activity thresholds under a rapid assessment monitoring network by Grains Research & Development Corporation (GRDC)
• purchase through participating retailers.

More information is available on the GPA website and the GRDC website.

Australian plague locusts are on our doorstep

Australian plague locusts can damage crops and pastures during outbreaks. When large numbers are present in New South Wales and Queensland, they often move into Victoria and can then breed.

Control is harder once locusts can fly and move in swarms. You will get the best results when you act early.

Choose the right chemical

Different chemicals control locusts in different ways. You must read the product label and choose a chemical that suits your situation.

Chemical groups include:

• Carbamate and organophosphate insecticides that break down quickly
• Phenylpyrazoles that work at low doses but can affect bees and waterways
• Biological products like Green Guard® that target locusts but act slowly.

For the latest updates on Australian plague locusts in Victoria, visit Australian plague locust.

Varroa mite treatment resistance detected

Varroa mites that do not respond to chemical treatment have been detected in Australia. Treatment resistance to both major synthetic treatment groups - pyrethroids and formamidines – has been confirmed in hives in Victoria, South Australia, New South Wales and Queensland.

Treatment resistance reduces the tools that can be used to control Varroa mites. If resistance becomes widespread, control of Varroa mites becomes difficult and can lead to:

• potential for mite numbers to increase quickly across apiaries
• increase likelihood of hives becoming stressed, with colonies weakening or dying.

In addition to the potential for resistant mites to spread, new resistance can also develop in colonies if the same chemical is used repeatedly without rotation between treatment groups. This includes products such as Bayvarol Strips, Apistan, Apitraz and Apivar 500mg Beehive Strips for Honeybees.

Monitor mite levels

Regular monitoring helps you detect treatment failure early. If you use synthetic chemicals such as pyrethroid or formamidine chemical groups, check your hives halfway through treatment. This will help you identify any problems early.

To slow resistance, use a mix of strategies such as:

• integrated pest management
• rotating chemicals with different chemical groupings
• following all label and permit conditions
• using non‑chemical controls where practical (e.g. mechanical controls like brood breaks)
• reducing reliance on synthetic miticides.

You should also manage swarming. This helps reduce the risk of mites spreading from feral bee populations and slows the spread and development of resistant mites.

If treatment failures are detected in your hives:

• Switch miticides to one that uses a different group, with non-synthetic options providing a good alternative to break the cycle
• Report the treatment failure, including suspected cases of treatment failure, to the Exotic Plant Pest Hotline on 1800 084 881.

For Varroa management advice, contact our Victorian Bee Biosecurity Officers on 136 186 or email honeybee.biosecurity@agriculture.vic.gov.au

Review of chlorpyrifos‑methyl begins

The Australian Pesticides and Veterinary Medicines Authority (APVMA) have announced a review of chlorpyrifos-methyl, which will include:

• all products containing chlorpyrifos-methyl,
• associated label approvals and
• the approvals of chlorpyrifos-methyl as an active constituent. 

Chlorpyrifos-methyl was prioritised for review due to potential:

• toxic impurities in the active constituent, and
• risks posed by the use of the chemical products to:
  • human health, such as worker safety and dietary exposure,
  • the environment and
  • international trade.

Chlorpyrifos-methyl is an organophosphate insecticide primarily registered for use as a protectant in un-infested stored grain.

The APVMA is seeking public consultation on the scope and reasons for the review now. Submissions will be accepted until 8 September 2026.

The time frame for the review is 42 months and commences at the close of consultation; however, a decision may be taken earlier if all assessments are completed.

Paraquat and diquat review

The Australian Pesticides and Veterinary Medicines Authority (APVMA) has published its final decisions on the extensive chemical review of non-selective herbicides paraquat and diquat.

The new rules aim to lower the risk of sudden exposure for those who handle these chemicals.

Changes include:

• phasing out the use of backpack sprayers
• requiring enclosed mixing and loading systems for all uses
• requiring enhanced personal protective equipment.

The maximum rate of application on paraquat and diquat will be 231 grams per hectare. Previously 1150 grams per hectare.

A higher application rate applies to technology assisted spot spraying where application is capped at 30% of total area.

Detailed information on new registration conditions for paraquat and diquat are available in the APVMA Special Gazette, 23 June 2026.

Chemical media in the spotlight 📣

Know the rules when spraying with drones

Drones, also known as remotely piloted aircraft, are increasingly being used for aerial spraying of agricultural chemicals, but operators need to be aware of the rules to keep people, animals and crops safe.

Agriculture Victoria’s Alex Perera said operators and pilots are required to be appropriately authorised by Agriculture Victoria and comply with Civil Aviation Safety Authority (CASA) requirements.

‘There are special licence categories under CASA and Agriculture Victoria to authorise and regulate piloting, spraying and business operations using drones for aerial spraying,’ Ms Perera said.

‘Similar to any sort of licence, these ensure operators and pilots hold the appropriate training and accreditations and understand their responsibilities when using drones.

‘Victoria’s agricultural chemical laws also apply to drone operators, in the same way as other aerial spraying contractors.’

Drone operator fined for causing spray drift damage

A south-west business was convicted and fined $15,000 in the Colac Magistrates’ Court for spray drift from aerial spraying via a drone.

Agriculture Victoria Manager of Regulatory Operations, Daniel Bode said ‘As use of these chemical application technologies increase, it’s important for people to understand they carry similar risks to other application methods.’

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Chemical use has been featured lately with our drone series and chemical planning for the upcoming table grape season.

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