The Australian Wine Research Institute

27 February 2026

Persistent rainfall events in the period from veraison to harvest can put vines under significant threat of disease − in particular botrytis bunch rot. Consequently, growers may be left with some difficult operational decisions.

Management strategies should be reviewed every few days as fruit ripeness and local weather conditions change. In some cases, activities including spraying or trimming may not be viable, or of limited value, and some crop loss or fruit remaining unharvested may be inevitable.

This eBulletin outlines key late-season management considerations relating to minimising botrytis infection and spread after rainfall events.

Botrytis bunch rot susceptibility

• Botrytis bunch rot, caused by the fungus Botrytis cinerea, affects dead, injured, or senescing grapevine tissue. It spreads fast in the presence of moisture, high humidity, mild temperatures (15–25°C), and when berries are damaged (by insects, heat or mechanical damage). Symptoms become more apparent as berries enlarge, change colour and begin to ripen.
• Thin-skinned varieties with compact bunches (e.g. Chardonnay, Riesling, Semillon, Chenin Blanc, Sauvignon Blanc, Pinot Gris, Traminer, Pinot Noir and Grenache) are most susceptible to infection, due to moisture retention and skin splitting. No varieties are immune to botrytis. Situations where there is bunch-to-bunch contact (often in higher yielding blocks) also lead to more rapid disease spread.

 

Considerations around fungicide spray decisions

Withholding periods – mandatory minimum time between chemical application and harvest that must be completed. This is termed the ‘export harvest interval’ for grapes destined for export wine as identified in the Agrochemicals registered for use in Australian viticulture booklet, commonly known as the ‘Dog book’, or the ‘withholding period’ for grapes destined for the domestic market (refer product labels).

Spray effectiveness – whether adequate spray coverage can be achieved for the active ingredient to be effective. Given the disease can start within the bunch and spread outwards, spray application to minimise botrytis on berries requires thorough coverage on the surface of and inside bunches. Late in the growing season, dense canopies can severely hamper sprays reaching this target bunch zone. Where vineyard access is possible, consider the need to trim or leaf pluck your canopy to enhance spray penetration at the bunch zone.

OH&S considerations – whether the health and safety of vineyard operators can be assured. Wet and slippery conditions can be dangerous for a tractor towing a heavy spray cart, especially on sloping ground. If safe access is not feasible, this can limit spraying or trimming opportunities.

 

Available fungicide options

The number of available spray options against botrytis reduces closer to harvest. Within 14 days of harvest, there is only a short list of spray options recommended for use on grapes destined for export wine. The following table is taken from Table 1 in the ‘Dog book’:

Active constituent	Activity group	Some registered products	Export harvest interval
Eugenol, geraniol, thimol	BM01	Novellus	Use no later than 14 days before harvest
Potassium salts of fatty acids	U1	Ecoprotector#, Hitman
BLAD	BM01	ProBlad, ProBlad Verde	Use no later than 7 days before harvest
Hydrogen peroxide + peroxyacetic acid	M+M	Peracetic Acid#, PeraCrop Max#, Peratec PLUS#, Peroxy Treat#
Aureobasidium pullulans	BM02	Botector	May be used until harvest
Bacillus amyloliquefaciens	BM02	Serenade Opti, Serifel

Biological products such as Aureobasidium pullulans (Botector) and Bacillus amyloliquefaciens (Serenade Opti, Serifel) act mainly as protectants and are most effective when applied before infection, or at very early stages of botrytis development. They can be useful late season where withholding periods restrict other spray options. A. pullulans works by colonising berry surfaces and competing with the pathogen, while Bacillus-based products suppress infection through naturally produced antifungal compounds. Biologicals may be beneficial after rainfall where berries remain intact, but provide limited control once berries are split or active botrytis is present. In such cases, cultural management practices or desiccant-type products (hydrogen peroxide + peroxyacetic acid or potassium salts of fatty acids) may be more appropriate. As for general fungicide application, adequate bunch-zone coverage is essential when applying any of the products listed in the above table, and rainfall after application may reduce persistence.

If a decision is made to spray:

• Refer to the ‘Dog book’ for options based on your expected harvest date and being able to meet export harvest intervals. Some fungicide groups and/or products are restricted or prohibited from use by some wineries. Refer to Table 2 in the ‘Dog book’and your winery/grape purchaser’s guidelines before you spray.
• Know how to avoid fungicide resistance in botrytis bunch rot and apply botrytis chemicals in line with the ‘Grey mould (botrytis bunch rot) resistance management strategy’ on page 16 in the ‘Dog book’.
• Always discuss pre-harvest spraying with your winery before making any applications.

 

Cultural management options

Promote airflow – where vineyard access is possible, consider slashing undervine and midrow to reduce humidity and promote air flow. This can provide a viable alternative to spraying.

Hand thinning of bunches – for high value, higher yielding blocks of thinner-skinned varieties, potentially weeks out from harvest – it may be economical to hand thin bunches, minimising bunch-on-bunch contact to slow down spread of botrytis.

Drop infected bunches – for high value blocks just prior to harvest, consider dropping infected bunches ahead of the mechanical harvester, or conducting selective hand harvesting.

Harvest adjustments – work with your winery to adjust your harvest timing and picking order so that at-risk blocks are picked first to minimise botrytis incidence and quality loss.

 

Further information

• Agrochemicals registered for use in Australian viticulture, the ‘Dog book’
• AWRI Botrytis webpage
• AWRI Botrytis information pack
• Wine Australia botrytis resources: Botrytis bunch rot | Wine Australia

 

Contact 

AWRI helpdesk phone: 08 8313 6600 (option 1)

Email: helpdesk@awri.com.au Website: http://www.awri.com.au

Address: Wine Innovation Central Building, Corner of Hartley Grove & Paratoo Rd, Urrbrae (Adelaide), SA 5064

 

Acknowledgement

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

 

 

 

18 November 2025

An election was recently held for two positions on the AWRI Board: one in the Grape Research Levy payer category and one in the large Wine Grapes Levy payer category.

The AWRI is pleased to announce that Peter Szabo (CCW Co-operative Ltd, SA) was elected in the Grape Research Levy payer category and Wayne Ellis (Ellis Castle Consulting, Vic) was elected in the large Wine Grapes Levy payer category.

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Peter Szabo is a vineyard owner and seasoned agribusiness leader with over four decades of experience across the Australian wine sector. He is currently the General Manager and Company Secretary of CCW Co-operative Ltd—Australia’s largest grower-owned grape supply organisation— overseeing operations, financial performance and strategic direction of a membership of nearly 500 winegrape growers. Peter is also a Director of CIT (Central Irrigation Trust).

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Wayne Ellis is a highly experienced people, strategy, supply and operations and process manager with over 25 years’ cross functional experience with medium to large FMCG companies. He has extensive experience across a wide range of industry sectors including wine, project management, supply chain management and operational management in the electronics industry. In previous roles at Duxton Vineyards, Accolade Wines, Zilzie Wines and Treasury Wine Estates, Wayne was responsible for overseeing the supply chain and operations across Australia and New Zealand. He is currently a consultant with Ellis Castle Consulting.

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Both Directors will commence their new elected terms on 1 January 2026. The terms of outgoing Board members Iain Jones and Damien Sheehan conclude on 31 December 2025. The AWRI thanks Iain and Damien for their contributions over their time on the AWRI Board.

5 November 2025

As we start another summer in Australia, it’s time to start thinking about plans for dealing with the possibility of bushfires and smoke. This eBulletin provides a reminder of the resources available to support growers and winemakers preparing for and managing smoke events. 

Resources available on bushfires and smoke taint 

• AWRI’s smoke taint page provides a comprehensive collection of resources on bushfires and smoke taint, including information on sampling, testing, interpretation of results, sensory impact and mitigation options. 
• Wine Australia’s website provides additional resources on fires and smoke, including case studies and podcasts. 
• State associations and Departments of Primary Industries have resources with specific information relevant to their state: 
  • Wine Victoria Bushfire Technical Response Program
  • Wine South Australia | Resources Hub | Bushfire resources
  • Bushfire Risk Management Research Hub | Fire | Environment and Heritage
  • Bushfires – PIRSA
  • TasVine smoke and vineyards
  • Wines of WA technical information

Heatwave and bushfire weather tools 

A number of agencies provide tools for tracking heatwaves, fires and air quality measures:

• BOM heatwave forecasts
• NASA fire information for resource management system (FIRMS)– active fire event locations
• Sentinel bushfire hotspots live interactive map
• PurpleAir citizen science air quality monitoring
• AirRater app

Smoke testing 

• AWRI recommends that sampling of grapes for smoke testing be conducted around three weeks before harvest, to allow enough time for transport of grapes to a testing facility and for the analytical testing of grapes. Provided the same analytical methods are used, results can be compared to AWRI’s comprehensive background database of smoke marker compounds to assist with interpretation. The publicly available database now contains data for 21 grape varieties grown in Australia. 

• Pre-veraison grapes or leaf samples should not be tested, because there is no background database for these samples to support results interpretation.  
• All results from testing by Affinity Labs (AWRI’s commercial arm) include graphical representations of the results in relation to the background levels database, to assist with interpretation. See this ‘Ask the AWRI’ article for more information. 

• Verbal interpretations of smoke analysis from any laboratories using the same methods as those used to establish the background levels can also be requested from the AWRI helpdesk. 

Capacity to deal with a significant smoke event 

• If a major smoke event occurs, AWRI will work with stakeholders and regional associations to share the most relevant technical information and optimise sample collection and transport. 

• Question & answer events can be scheduled in affected regions, where needed, in consultation with local regional associations. These will most likely be delivered online or in a hybrid format. 

• There is an option for sample preparation in-region to be supported to speed up testing. 
• Affinity Labs has increased its smoke testing capability since 2020 and plans are in place to quickly ramp up analysis if a major smoke event occurs. 

Greater understanding of the risk of smoky wines based on testing of grapes 

• Following a major collaborative research project conducted during the 2020 vintage, more information is now available to help producers assess the risk of smoky wines based on grape analysis. 

• Results have been peer-reviewed and published as an open access article in the Australian Journal of Grape and Wine Research. There is also an industry article Recent smoke research and what it means for industry that summarises the knowledge gained since 2020. 

• This work confirmed that the current suite of 13 smoke exposure markers in grapes could predict smoky flavour in wine in three varieties (Chardonnay, Pinot Noir and Shiraz). 

• Table 5 of the paper summarises the concentrations of smoke markers in grapes that produced smoky wines in the study, noting that the trial did not apply any remediation to address the smoke impact. The information on the AWRI website has been updated with information about aged smoke-affected wines. Full details on the aged wines can be found in this article, which is available on request from the AWRI library.  Parker, M., Bilogrevic, E., Jiang, WW., Wilkes, E., Francis, L., Herderich, M.J. 2025. Bottle aging of smoke-affected wines: changes in smoke flavor and chemical composition. J. Agric. Food Chem. (s2431) 

• Other studies have shown that applying remediation techniques can reduce the impact of smoke in some wines. 

 

For more information or assistance with planning for future smoke events, please contact the AWRI helpdesk on helpdesk@awri.com.au or 08 8313 6600. 

AWRI’s eBulletin is supported by Wine Australia, with levies from Australia’s grapegrowers and winemakers and matching funds from the Australian Government. 

3 November 2025

Voting is now open in the election for two vacant positions on the AWRI Board of Directors in the Grape Research Levy payer (grapegrower) and the large (50,001+ tonnes) Wine Grapes Levy payer (wine producer) categories. One position in each category will be filled.

Levy payers in each category nominated the following candidates:

Grape Research Levy payers
Matthew Deller (CEO, Wirra Wirra Vineyards, Ashton Hills and Hahndorf Hill, SA)
David Lloyd (Winemaker, Tas)
Jamie Saint (Chief Winemaker, Australian Vintage Ltd, SA)
Damien Sheehan (General Manager/Viticulturist, Mount Langi Ghiran, Vic)
Peter Szabo (General Manager, CCW Co-operative Ltd, SA)

Large Wine Grapes Levy payers
Wayne Ellis (Consultant, Ellis Castle Consulting, Vic)
Rob Glastonbury (Operational Manager, De Bortoli Wines, Vic)
Iain Jones (Global Quality & Technical Services Manager, Treasury Wine Estates, SA)
Jean Macintyre (Project Lead – Liquid Innovation, Vinarchy, SA)
Steve Warne (Chief Winemaker, Kingston Estate Wines, SA)

Voting instructions and candidate profiles (Grape Research Levy payer candidates and Large Wine Grapes Levy payer candidates) are available on the AWRI website or you can access the voting page directly. The ballot will close at 5:00 pm CST on Friday, 14 November 2025.

Levy payers in each category are strongly encouraged to vote for their preferred candidate. Only Grape Research Levy payers (grapegrowers) are eligible to vote in the Grape Research Levy payer category and only large Wine Grape Levy payers are eligible to vote in the large Wine Grapes Levy payer category.

This is an excellent opportunity to have a say in electing a candidate that can contribute to the Australian grape and wine research and development agenda.

 

Need help deciding if you are eligible to vote in this election?

The Grape Research Levy (GRL) is the levy payable on fresh grapes, dried grapes and/or grape juice produced in Australia and delivered to a processing establishment in Australia. A GRL payer is an organisation (sole producer/partnership/company) that is liable to pay the GRL even if the actual levy is remitted by a winery on your behalf.

The Wine Grapes Levy (WGL) is the levy payable on grapes used in the winemaking process. A large WGL payer is an organisation that crushes more than 50,000 tonnes of grapes per annum.

You may be eligible to vote in both categories.

The election will be conducted electronically with assistance from Elections Australia Pty Ltd.

 

VOTING PERIOD NOW OPEN
The ballot is now open and voting has commenced. The ballot will close at 5:00 pm CST on Friday, 14 November 2025.

 

VOTING INSTRUCTIONS

1. Go to: http://www.myvote.com.au/awri and follow the instructions.
2. Enter the name of the levy payer (the organisation liable to pay the levy) and the person submitting the vote on behalf of the levy payer.
3. Cast your vote.

A levy payer organisation may only vote once in each election in which they are eligible to vote. The following representatives are eligible to vote on behalf of the levy payer organisation:

• Sole owner
• Partner of a partnership
• Director (or Director equivalent) of a Company or group of Companies.

Results of the election will be announced in the week commencing 17 November 2025 via the AWRI’s eBulletin and will also be published on the AWRI website.

For further information please contact the Returning Officer, Shiralee Dodd at returningofficer@awri.com.au.

For other enquiries
please contact
enquiries@awri.com.au
08 8313 6600