The Australian Pesticides and Veterinary Medicines Authority’s (APVMA) has released its final decision following its review of paraquat and diquat.

For fallow use, the maximum rate of paraquat products has been set at 231 g active per hectare, and paraquat/diquat products at 251 g active per hectare (equivalent to 1 L/ha of SpraySeed). These rates are lower than what many growers currently rely on for control of hard-to-kill weeds in fallow situations, and industry feedback has highlighted they are unlikely to provide reliable control of some key weeds currently targeted in cotton fallows, particularly larger or stressed weeds.

All registrations specific to cotton have been removed from labels for products containing paraquat and diquat. This specifically means that these products can no longer be used for crop desiccation or control of cotton volunteers. This change will particularly impact production of dryland cotton, where these use patterns have been a vital part of the production system. 

For optical spot spraying systems, use has been allowed up to 770 g active per hectare (around 3 L/ha of a 250 g/L product). This is a significant reduction from the previous allowance of up to 9 L/ha. Cotton Australia and industry submissions also raised concerns that the APVMA assumption of 30% ground coverage with optical sprayers is too high, with field data indicating average coverage is closer to 10%, which affects how practical and effective the new settings will be in real paddock conditions.

Other changes include the phase-out of backpack sprayers, requirements for enclosed mixing and loading systems, and increased personal protective equipment (PPE) requirements across all uses. Cotton Australia supported these changes to occupational safety in our response to the review in 2024.

The Cotton Australia submission called for the retention of some of the previous label conditions based on concerns about the applicability of the environmental modelling used in the review. The APVMA has ultimately chosen to reduce products rates in accordance with the environmental modelling, with some minor adjustments based on the feedback they received.

Transition arrangements

• Product already in the supply chain (on shelves, in warehouses) as of the announcement may continue to be used in line with its existing label for up to two years.
• This is a maximum window to use down existing stock, not a blanket two-year delay. All product manufactured after the announcement date must carry the new label, and once new-labelled stock is purchased it must be used according to the new instructions.

Next steps

These changes will affect fallow weed and volunteer control, where paraquat is used as part of double knock strategies and to manage resistant weeds. 

Cotton Australia is working with Crop Consultants Australia and the Cotton Research and Development Corporation (CRDC) to assess what these changes mean in cotton systems. This includes reviewing current fallow practices, testing alternative weed control options, and looking at how different products can be used together in spray programs to better manage weeds under the new rules. This will include looking at the opportunity to seek additional product registrations for volunteer control and crop management, and the possibility of tank mixtures with other products to improve efficacy and reduce the risk of herbicide resistance developing. We will be exploring opportunities to commission research or work with registrants to address these issues in a constructive way.