GRDC is focused on reducing the off-site drift of agricultural chemicals.
Mitigating the risk of spray drift is an important issue for the cropping industry, threatening the availability of valuable pesticide options and the industrys social licence to operate. The GRDC continues to invest in both spray drift reduction techniques, along with research to ensure growers are supported to maintain spray efficacy.
As well as urging growers to comply with the new use instructions for 2,4-D, industry groups are also stressing to growers the need to focus on preventing off-site spray drift across all chemical applications.
Strategies to help prevent spray drift include:
- Do not spray during a surface temperature inversion
- Use the coarsest spray quality possible
- Keep the boom height low
- Reduce speed below 22 kilometres an hour
- Avoid using adjuvants that decrease droplet size.
Changes to 2,4-D use
Grain growers and spray operators can now access a practical guide explaining how to maintain efficacy when using coarser spray qualities in line with new restrictions to the use of 2,4-D.
The guide has been developed by the GRDC to assist industry understand the on-farm implications of the Australian Pesticides and Veterinary Medicines Authority (APVMA) decision to suspend the labels of all products containing the active ingredient 2,4-D from October 4, replacing them with a permit.
The action by the APMVA was taken in response to widespread damage over several years to sensitive crops, such as grapes, horticultural crops, summer pulses and cotton.
The APMVA permit will stay in place until the finalisation of the 2,4-D review.
Under the permit there are changes to the directions for use for 2,4-D, including:
- Changes to application technique
- Spray quality
- The observance of mandatory no-spray buffer zones
- Increased requirements for detailed record keeping.
Industry spray specialist Bill Gordon, who has done extensive work on best practice application, has helped to develop the latest GRDC guide to 2,4-D use, for those working in the paddock.
Mr Gordon says it is important to understand the new changes were primarily targeted at drift mitigation and do not restrict any other aspects of the current approved use patterns as detailed in the new permit, which replaces the current product labels.
Mr Gordon says the key changes for using 2,4-D under the permit mean applicators must now use at least a Very Coarse (VC) spray quality.
Also when using a boom sprayer, boom heights must be 0.5 metres or less, as measured from the target height.
Downwind buffers also apply, typically less than 50m, subject to rate and product being applied, between application sites, downwind sensitive crops and environmentally sensitive aquatic areas.
Mr Gordon says the new permit also includes an advisory statement for 2,4-D use in cereals, fallow and pasture from October 1 to April 15. These statements advise operators to use an Extremely Coarse (XC) or Ultra Coarse (UC) spray quality and to take steps to mitigate the risk of spray drift, such as adopting increased water rates and slower application speeds.
Additional record keeping is also required under these changes, so operators now need to update spray records, with greater detail, within 24 hours of application and to keep these records for a minimum of two years, he says.
The permit also includes clearer instructions to help identify temperature inversions to reduce off-target spray risk.
I would advise operators to watch for weather changes and stop spraying immediately if a surface temperature inversion develops or conditions become unsuitable for any other reason.
Mr Gordon says the changes will mean many spray operators will have to buy additional sets of nozzles to meet the new requirements for VC, XC or UC spray quality.
Operators are encouraged to contact their suppliers well before starting spray activities to secure the supply of their nozzle requirements," he says.
Mr Gordon says operators will also need to consider adjusting application volumes when using coarser spray qualities.
Additional record keeping is also required under these changes, so operators now need to update spray records, with greater detail, within 24 hours of application and to keep these records for a minimum of two years.
When increasing the droplet size, it is important to consider increasing the total application volume to maintain coverage and efficacy, Mr Gordon says.
In low stubble environments a minimum of 70 litres per hectare has been shown to provide acceptable efficacy when using XC spray qualities. In heavier stubble this may need to be increased to 80L/ha or more.
Mr Gordon says there are additional state and territory restrictions, which spray operators and growers must adhere to, that may include restricted areas and the times chemicals could be used. Operators are advised to check with their relevant state authority for details.
Investing on the ground
GRDC crop protection officer North Vicki Green says the GRDC is continuing to take a multi-pronged approach to support efforts to eliminate off-target spray drift.
On the ground we are supporting a number of workshops across Australia aimed at educating growers in how they can reduce spray drift while maintaining spray efficacy, she says.
We are continuing to liaise with the wider industry, including the chemical companies, spray application experts, government agencies, machinery companies and grower representative organisations.
Research is important, work is continuing to improve our understanding of spray efficacy under different atmospheric and environmental conditions.
This issue requires a whole-of-industry approach. We all need to play a part in preventing spray drift.
- Visit grdc.com.au/spray-drift for best practice information.