The Australian Wine Research Institute

11 September 2024

Phenoxy herbicide spray drift onto vineyards is a relatively common occurrence, resulting in grapevine damage and potential residue issues.

This agrochemical update provides a reminder of the damage to look out for, and who to contact to report spray drift damage to grapevines, or potential cases of off-label herbicide application.

Damage to look out for

Grapevines are sensitive to phenoxy herbicides such as 2,4-D. Exposure can lead to adverse effects on yield, vegetative growth, vine health and overall fruit quality.

Typically, symptoms of 2,4-D exposure in grapevines are first noted as distorted leaf tissue (Figure 1); observed mostly in young developing leaves. Other symptoms include tendril necrosis, zig-zag shoots and curled leaves. Symptom severity is generally related to a range of factors including chemical dose strength, timing and number of exposure events, as well as vine age. Grapevine yield has been shown to be impacted both in the season of exposure and the season thereafter, with respect to bunch number and bunch size.

Figure 1. Distorted grapevine leaf tissue from 2,4-D herbicide spray drift. Image courtesy of Anna Baum, Clare Valley Wine & Grape Association.

For assistance in identifying the cause of spray drift based on vine damage symptoms, refer to this Rossouw (2018) report.

Reporting spray drift incidents

Agricultural chemical users have a legal obligation to make sure chemicals are applied according to label directions and products stay within the target area.

If vine or crop damage occurs as a result of off-target spray drift from outside your property; or you become aware of non-compliant chemical use, this should be immediately reported to the appropriate authority for further investigation.

Responsibility for addressing incidents of off-target spray drift sits with each state and territory government. Refer below for contact details for the relevant organisation. Further details are also provided on the Australian Pesticides and Veterinary Medicines Authority website. If you are in any doubt, please contact the AWRI helpdesk for assistance.

Reporting cases of spray drift

NSW
NSW Environment Protection Authority
Phone: 131 555 for the EPA’s Environmental line
Web: Preventing pesticide misuse (nsw.gov.au)

QLD
Biosecurity Queensland
Phone: 13 25 23
Web: Reporting chemical spray drift | Business Queensland

SA
Biosecurity SA Agricultural and Veterinary Chemicals Hotline
Phone: 1300 799 684
Email: pirsa.ruralchemicals@sa.gov.au
Web: Reporting chemical misuse – PIRSA

TAS
AgVet Chemicals Program
Phone: 03 6777 2133
Email: agvetchemicals@nre.tas.gov.au
Web: Spray Drift and Reporting Incidents | Department of Natural Resources and Environment Tasmania (nre.tas.gov.au)

VIC
Agriculture Victoria
Phone: 136 186

WA
WA Department of Health
Phone: 08 9222 4222

Testing vines, grapes or wine for spray drift residues

Depending on the circumstances of the spray drift incident and grape purchaser requirements, you may consider residue testing of foliage, fruit or wine. Contact the Affinity Labs team on (08) 8313 0444 or via email at customerservice@affinitylabs.com.au to discuss.

For further information about spray drift or any other grape and wine technical issues, please contact the AWRI helpdesk on (08) 8313 6600 or email helpdesk@awri.com.au.

Acknowledgements

The AWRI’s eBulletin is supported by Wine Australia, with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. The AWRI is a member of the Wine Innovation Cluster in Adelaide, South Australia.

6 September 2024

Paraquat and diquat agrochemicals have been used in Australia since the mid 1960’s as non-selective contact herbicides and plant tissue desiccants. Current use of these actives in vineyards is for post-emergent weed control, as part of a toolkit including other actives such as glyphosate and glufosinate-ammonium.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) has recently completed a Technical Review of paraquat and diquat, in the areas of: (a) toxicology of both the active constituents and products, (b) worker health and safety, (c) residues and trade assessment, (d) environment safety including spray drift. The APVMA’s proposed regulatory decisions were reported in a Special Gazette dated 30 July 2024 including that future use of these actives in vineyards is not supported. Environmental impacts have been reported as a key contributor to this decision – specifically the off-target impact on wild birds and wild mammals for paraquat, and impact on wild birds for diquat. Future use in many other crops is also at risk.

Some key determinations/proposed recommendations from the review include:

• Paraquat rated as having high toxicity to mammals and birds. Diquat rated as having high toxicity to birds and moderate toxicity to mammals.
• Paraquat use in vineyards (whether alone or in combination with another active) is not supported above a maximum of 45 grams of active ingredient per hectare, applied as a single application per year. This is well below the current maximum of 800 grams of active ingredient per hectare for vineyard application.
• Diquat use in vineyards (whether alone or in combination with another active) is not supported above a maximum of 88 grams of active ingredient per hectare, applied as a single application per year. This is well below the current maximum of 368 grams of active ingredient per hectare for vineyard application.
• For both paraquat and diquat actives – closed mixing and loading equipment required for all use situations; maximum handling rates per day by use and by active; no allowable application via backpack sprayer.
• Additional spray drift restrictions (around wind speed, inversion layers, nozzle size) and downwind buffer zones.
• Labels – additional headings related to the poison schedule for paraquat and combination paraquat labels only; addition of General restraints, Restraints for specific uses, First Aid and Safety directions, and Re-entry statement to all labels; additional export slaughter interval statement (paraquat and combination paraquat labels only), update of grazing statement and risk management statements relating to toxicity to birds and native mammals and aquatic life.
• A decrease in Maximum Residue Level (MRL) for paraquat from 0.05 to 0.01 mg/kg applicable to grapes.

The paraquat and diquat reviews are now in the consultation phase until 29 October 2024,during which time feedback can be provided to the APVMA on the proposed recommendations.

The wine industry is considering the proposed changes and working to assess these with other crop groups.

Following the APVMA’s review of the consultation stage submissions, they will publish their final regulatory decisions. For diquat this is expected to be in the week commencing 28 January 2025, and for paraquat in the week commencing 28 February 2025; at which stage the implementation periods will also begin.

Submissions

The wine industry’s national bodies are collectively staying abreast of discussions surrounding the paraquat and diquat reviews and are considering options around making submissions to the APVMA.

Interested parties wanting to either request further information or make a submission, can do so directly to:

Chemical Review Australian Pesticides and Veterinary Medicines Authority

GPO Box 3262

Sydney NSW2001

Phone: +61 2 6770 2400

Email: chemicalreview@apvma.gov.au

Submissions will be published on the APVMA website, unless you ask for the submission to remain confidential.

For questions about the paraquat and diquat review, or any other technical viticulture or winemaking question, please contact the AWRI helpdesk on 08 8313 6600 or helpdesk@awri.com.au.

Acknowledgements

The AWRI’s eBulletin is supported by Wine Australia, with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. The AWRI is a member of the Wine Innovation Cluster in Adelaide, South Australia.

2 September 2024

With budburst upon us in a number of wine regions, it is a good time to reflect on some of the key factors that support safe and effective vineyard spray practices for pest, disease and weed control.

Chemical selection

Limit agrochemical application in your vineyard to only those active ingredients and products registered for use on grapevines. You can find full list of registered agrochemical active ingredients, those which are recommended for use in vineyards and a range of associated products containing these actives, in the ‘Dog book’.

Chemical labels

Agrochemical labels are legal documents that must be observed. Always follow the label recommended application rates; personal protective equipment and safety requirements; spray drift restrictions including buffer zones, wind speed and temperature inversions; grazing restrictions; re-entry periods; and storage and disposal requirements.

Labels also include withholding periods (WHPs) relevant to the sale of wine domestically in Australia. The ‘Dog book’ WHP recommendations assume wine will be sent to a range of overseas markets, each with differing maximum residue levels (MRLs) for chemical active ingredients. If your grapes are destined for wine which is only sold in Australia, or to only a few countries, contact the AWRI to discuss how the WHP recommendations might differ. The AWRI can also provide advice regarding the persistence of chemicals on grapes or through winemaking. MRLs for most major export destinations can be found in the AWRI’s MRL database.

Chemical application

Effective chemical control is dependent on the appropriate product, timing, dosage and coverage. A number of fact sheets on spray application are available from the spray application page of the AWRI website. Key points to consider include:

• Spray drift – monitor weather conditions before and during spraying to minimise off-target application. Practical tips for spraying can be found in this video.
• Safety – all staff who handle and apply agrochemicals should be adequately trained to perform the task safely. Refer to your state regulations for chemical accreditation and requirements.
• Disposal – recycle used and eligible Australian agricultural and veterinary chemical containers through the national drumMuster program. Dispose of unused or obsolete chemicals responsibly through the ChemClear program.

Chemical record-keeping

Records of use of agricultural chemical products in vineyards are required by law. Details of agrochemical applications must be kept for a minimum of two years from the date of use.

The AWRI, in collaboration with industry, developed a spray diary format and set of terminology that meets basic winery requirements. However, it is recommended that growers follow applicable state or territory rules for record-keeping and check requirements with individual winery or grape purchasers prior to the commencement of the spray season.

Chemical resistance management

To ensure longevity and efficacy of vineyard chemicals, be mindful of rotating chemical actives. To better understand chemical resistance and how it occurs, read CropLife Australia’s recommended chemical resistance management strategies, refer to pages 15 – 18 of the ‘Dog book’ and the AWRI fact sheet on managing chemical resistance in the vineyard.

For more information on spray application or any other grape and wine technical issues, please contact the AWRI helpdesk on (08) 8313 6600 or email helpdesk@awri.com.au.

Acknowledgements

The AWRI’s eBulletin is supported by Wine Australia, with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. The AWRI is a member of the Wine Innovation Cluster in Adelaide, South Australia.