The Australian Wine Research Institute

3 November 2023

El Niño seasons are known for clear cloudless days, lower rainfall, higher day temperatures and lower night temperatures, which together increase the chance of frosts. The AWRI helpdesk has recently received reports of frost damage to grapevines from regions across SA, WA, Victoria, NSW and the ACT. This eBulletin outlines key factors to consider when deciding what action to take after a frost and points to some useful resources to learn more about frosts and how to mitigate against them.

Due to the variable nature of frosts (temperature and duration) combined with the variability of vineyards (growth-stage, variety, pruning system, target yield, value and quality etc) and the variable growing season duration between regions, there is no single or simple answer to the question of what to do after a frost. The key factors to consider are outlined below when deciding how to respond to a frosted vineyard situation by assessing a few different scenarios.

The desire to act quickly after a frost is strong because you are seeing your vines in trouble, and you want to do something. The best thing you can do is to wait at least a week to assess the extent of the damage. Frost symptoms on leaves can show after a few days, while the impact on inflorescences can take a week or more to appear. It is also sensible to wait until the risk of frost has gone before acting, because another frost could change your plans. When the risk of frost has passed, conduct a careful vineyard assessment of where the damaged vines are and the extent and severity of the damage. If you decide you are going to take action, it is then recommended not to delay because the vine is expending energy to adjust to what has occurred.

Scenario 1. Light frost

If the assessment reveals that the damage to the crop is light overall, no immediate action is required. The damaged tissue may be susceptible to Botrytis if wet weather follows the frost, so this should be considered in future disease management strategies.

Scenario 2. Severe frost early in the season (up to E-L 11)

If the shoots were small and subjected to a severe frost (up to E-L 11, four leaves separated), there is no need to act because the vine will replace the lost primary shoots with a secondary shoot and the damaged shoot will shrivel up over time. The replacement shoot will not be as fruitful as the primary shoot, but there should be a crop and fruit development should be relatively uniform. The secondary shoots should have time to lignify at the end of the season and provide good pruning options. Once new growth emerges and has reached E-L 12, a nitrogen application can assist the new growth as the vines used up their early season reserves.

 Scenario 3. Frost damage post E-L 11

The most difficult situation to manage is where a moderate frost occurs in a vineyard at a growth stage later than E-L 12. When well-developed primary shoots are only partially damaged and the shoot tip is killed, lateral shoots will be strongly stimulated to grow from the leaf axis on the healthy parts of the primary shoot. In this situation, there is the possibility of fruit setting from inflorescences that survived on the primary shoots as well as those coming from secondary shoots that burst plus any fruit from laterals. At harvest, this leads to variable ripeness and poor fruit quality. This lateral growth can also lead to a crowded canopy and those shoots provide poor pruning material for the following season.

Trials that have assessed post-frost options (largely ‘do nothing’ vs removing damaged primary shoots) have had variable outcomes. In terms of yield the following season, neither approach is consistently better. A ‘do nothing’ strategy is cost-effective in the season in which the frost occurred, but it can come at the expense of the following season when pruning options are poorer and yield is impacted as a result. Action to remove the damaged primary shoots down to the compound bud to encourage a secondary shoot is an expense that needs to be considered in terms of the impact that it has on fruit quality in the current season as well as at pruning time. For cane-pruned vineyards, having good replacement canes is critical and the ‘do nothing’ strategy may not be conducive to this.

Considerations when deciding what action to take:

• Length of the growing season: In a cool region, is there time to fully ripen a new crop? If not, the only option for a ripe crop this season is to focus on the fruit remaining on primary shoots after the frost.
• Wine quality expectations: Can you tolerate a lower grade of fruit caused by uneven ripening? If not, removing green bunches at veraison may be necessary.
• Pruning: Can you tolerate poor-quality replacement canes and spurs? If not, then intervening post-frost may be necessary.
• Assess the cost of any proposed action: A small trial can tell you the time it takes to undertake a post-frost intervention. Assign a value to this time and assess against the value of the crop or other potential benefits.
• Inputs: Is there an opportunity to reduce some inputs to reflect the lighter crop? The cost/benefit ratio of managing a lower yielding crop needs to be considered. The season has already started and now is potentially starting over. It is difficult to spend more than what was intended for the year, so consider if some management operations and vineyard passes are still necessary.

Frost warnings

Designed for agriculture, the Bureau of Meteorology (BOM) provides Frost potential maps, which show forecast low temperature thresholds for various locations across Australia. The maps are updated each day and show forecasts for the next 48 hours. More information about the Bureau of Meteorology’s frost risk outlook and frost warning service can be found in this AWRI webinar (5 September 2019). Some regions and associations have additional weather stations and/or frost warning services.

Ways to reduce the risk of frost damage

Passive methods include site selection, soil management, trellis design, variety choice and pruning method/timing. For established vineyards, active methods require energy to reduce longwave radiation loss to the sky, or to directly warm the air near to the soil. These include sprinklers, air mixing, heating and foliar sprays. More information on these methods can be found in the following resources:

• Frost management in vineyards (AWRI factsheet)

• Protecting your vineyard from frost (AWRI demonstration video)
• Managing frost (AWRI webinar 29 September 2020)

 Additional information:

• AWRI frost information pack
• Frost control in New Zealand vineyards. New Zealand Wine booklet (2020).

 Further assistance

For assistance with frost or any other technical viticulture or winemaking topic, contact the AWRI helpdesk on (08) 8313 6600 or helpdesk@awri.com.au.

Acknowledgements

Liz Riley (Vitibit) and Dr Peter Dry are thanked for their contributions to this eBulletin.

This work 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, SA.

26 October 2023

Voting is now open in the election for a vacant position on the AWRI Board of Directors in the medium (2,001 – 50,000 tonnes p.a.) Wine Grapes Levy payer (wine producer) category.

Levy payers in the medium category nominated the following candidates:

Brett McClen (Brown Family Wine Group, Vic)
Courtney Ribbons (Pernod Ricard Winemakers, SA)

Voting instructions and candidate profiles 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,17 November 2023.

Levy payers in the medium category are strongly encouraged to vote for their preferred candidate. 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.

Nominations were also called for in the small (less than 2,000 tonnes p.a.) Wine Grapes Levy Payer category. As only one nomination was received in that category, an election is not required. The AWRI is pleased to announce that Corrina Wright of Oliver’s Taranga has been re-elected to the position of small Wine Grapes Levy Payer Director.

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

The Wine Grapes Levy (WGL) is the levy payable on grapes used in the winemaking process. A medium WGL payer is an organisation that crushes between 2,001 and 50,000 tonnes of grapes per annum. Only medium WGL payers are eligible to vote.

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, 17 November 2023.

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 this election. 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 27 November 2023 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.

17 October 2023

Nominations are closing this Friday for two levy payer-elected Director positions on the Board of The Australian Wine Research Institute Ltd (AWRI). The AWRI Board includes three people who are nominated and/or elected by Wine Grapes Levy payers and one person who is nominated and/or elected by Grape Research Levy payers, with terms of three years. In accordance with the Constitution of the AWRI, two of these positions become vacant on 31 December 2023: one in the small Wine Grapes Levy payer category and one in the medium Wine Grapes Levy payer category.

 

This is an excellent opportunity for an interested candidate to become involved in the Australian wine industry’s own R&D organisation and, in addition to their other duties and responsibilities, provide a ‘coalface’ perspective to the direction and priorities of AWRI’s research, development, extension and commercialisation activities.

 

Current levy payers are invited to nominate suitably qualified candidates for the vacant positions. Nominations must be made in writing on the official nomination form which is available from the Election and Appointment of Directors page on the AWRI website. Eligible levy payers may propose or second one nomination only.

 

Nominations are to be received by post to The Returning Officer, The Australian Wine Research Institute Ltd, PO Box 197, Glen Osmond SA 5064 or by email to returningofficer@awri.com.au NO LATER THAN 5 PM FRIDAY, 20 October 2023. If more than one nomination is received in each category, an election in that category will be conducted during November 2023.

 

Nominees are encouraged to prepare a profile/statement of not more than 250 words, including a photograph, in support of their nomination, for use in the event that an election is required. The profile/statement must also be received by the AWRI Returning Officer by the nomination deadline of this Friday, 20 October 2023.

 

More information is available in the nomination form regarding:

• the definition of small and medium Wine Grape levy payers

• the clauses of the AWRI Constitution dealing with the election of Directors by levy payers and their term of office.

A form can also be requested by contacting Shiralee Dodd, the Returning Officer, by email at returningofficer@awri.com.au.

After several months of El Niño watch, the Bureau of Meteorology declared on 19 September 2023 that an El Niño event and positive Indian Ocean Dipole are underway in Australia. The declaration of these events, and their concurrence over spring, reinforces the Bureau’s long-range rainfall and temperature forecasts, which predict warmer and drier conditions for much of Australia over spring and summer. This also translates to an increased risk of bushfires, following three years of wetter seasons, which have increased fuel loads. Early-season fires have already occurred across several states. The purpose of this eBulletin is to support producers in preparing for and managing smoke events, provide tips about testing and deliver a brief summary of new information gained from research conducted on smoke since 2019/20.

Resources available on bushfires and smoke taint 

• The 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 fire and smoke emergency plan
  • NSW BushfireHub
  • SAWIA Bushfire Resource
  • TasVine smoke and vineyards
  • Wines of WA Technical Information

 

Heatwave and bushfire weather tools 

• BOM heatwave forecasts
• NASA fire information for resource management system (FIRMS) – active fire event locations
• Sentinel bushfire hotspots live interactive map

 

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 optimise sample collection and transport to ensure the smooth flow of samples to testing laboratories and the shortest possible analytical turnaround times.
• Question & answer events can be scheduled in affected regions, where needed, in consultation with local regional associations.
• There is an option for sample preparation in-region to be supported to speed up testing.
• Affinity Labs has increased its smoke testing capacity since 2020 and plans are in place to quickly ramp up analysis if a major smoke event occurs.

 

New 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.
• 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. 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.

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.

28 September 2023

Invitation to nominate levy payer-elected Directors to the AWRI Board

Nominations are now open for two levy payer-elected Director positions on the Board of The Australian Wine Research Institute Ltd (AWRI). The AWRI Board includes three people who are nominated and/or elected by Wine Grapes Levy payers and one person who is nominated and/or elected by Grape Research Levy payers, with terms of three years. In accordance with the Constitution of the AWRI, two of these positions become vacant on 31 December 2023: one in the small Wine Grapes Levy payer category and one in the medium Wine Grapes Levy payer category.

This is an excellent opportunity for an interested candidate to become involved in the Australian wine industry’s own R&D organisation and, in addition to their other duties and responsibilities, provide a ‘coalface’ perspective to the direction and priorities of AWRI’s research,development, extension and commercialisation activities.

Current levy payers are invited to nominate suitably qualified candidates for the vacant positions. Nominations must be made in writing on the official nomination form which is available from the Election and Appointment of Directors page on the AWRI website. Eligible levy payers may propose or second one nomination only.

Nominations are to be received by post to The Returning Officer, The Australian Wine Research Institute Ltd, PO Box 197, Glen Osmond SA 5064 or by email to returningofficer@awri.com.au NO LATER THAN 5 PM FRIDAY, 20 October 2023. If more than one nomination is received in each category, an election in that category will be conducted during November 2023.

Nominees are encouraged to prepare a profile/statement of not more than 250 words, including a photograph, in support of their nomination, for use in the event that an election is required. The profile/statement must also be received by the AWRI Returning Officer by the nomination deadline of 20 October 2023.

More information is available in the nomination form regarding:

• the definition of small and medium Wine Grape levy payers

• the clauses of the AWRI Constitution dealing with the election of Directors by levy payers and their term of office.

A form can also be requested by contacting Shiralee Dodd, the Returning Officer, by email at returningofficer@awri.com.au.

Three new appointments

The AWRI Board also recently announced the appointment of three Directors: Trish Barry, Carolyn MacDonald and Damien Sheehan. Ms Barry and Ms MacDonald were appointed following a recruitment process conducted by the AWRI Nominations Committee. Damien Sheehan was appointed to the Grape Research Levy payer elected position left vacant following the resignation of Andy Clarke in August, as the next highest voted candidate in the 2022 election, to reflect the wishes of Grape Research Levy payers. These three Directors will take office on 1 November 2023.