Paraquat and diquat use escapes ban, restrictions to apply

NON-selective herbicides paraquat and diquat will remain in use following a review conducted by the Australian Pesticides and Veterinary Medicines Authority.

While still available to use, significant new restrictions on application rates and permitted uses will apply.

The chemicals are banned in more than 70 countries including the UK and all of the European Union.

The authority’s chief executive officer, Scott Hansen, said the reviews applied contemporary risk management frameworks to rigorous scientific investigation of the impacts of paraquat and diquat on human health and the environment.

“To protect users from acute exposure, new restrictions will phase out backpack sprayers and require enclosed mixing and loading systems for all uses, and enhanced personal protection equipment,” he said.

“Overall, the maximum rate of application on paraquat and diquat will be 231 grams per hectare, when it was previously 1150 grams per hectare.”

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

Detailed information on new registration conditions for paraquat and diquat are available in the authority’s special gazette published on 23 June.

In its update last week, the authority said the restrictions are driven by acute toxicity risks for people handling the Schedule 7 poisons and a detailed assessment of data showing acute and chronic exposure risks to birds and mammals foraging in treated areas.

During the review process the authority received 171 submissions from scientists, doctors, the agricultural industry and other interested parties.

Submissions on paraquat and diquat included a range of concerns including human health impact, farming viability and environmental impact.

The authority considered submissions which provided detailed scientific information or argument in line with contemporary international data requirements and test guidelines.

Among the agricultural organisations to make submissions regarding the matter was Cotton Australia.

Cotton Australia’s 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.

Cotton Australia also supported changes to occupational safety with increased personal protective equipment requirements across all uses also forming part of the outcome.

In response to last week’s announcement, Cotton Australia said the 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,” Cotton Australia said last week.

“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.”