Vineyard redevelopment

Choosing the right approach for your vineyard

When vineyard profitability is tight, growers may need to make significant decisions to secure their businesses’ future by addressing:

• Ageing or diseased vines
• Changing climate and potential disease risks
• Low demand and associated prices for the grapes they grow

The options available differ in complexity and expense but three stand out as being able to restore production in a relatively short timeframe:

Key points

• Challenging vineyard productivity or profitability may require significant decisions regarding the future of under-performing blocks.
• Three solutions that restore vineyards to full production relatively quickly are: 1) reworking vines from a new bud, 2) top-working a new variety, or 3) resting vineyards for a season or two.
• Triggers for action include vine age, trunk disease, declining cordons, market trends and financial viability.
• Reduced vine performance due to other management factors, such as soil health, irrigation effectiveness and pest and disease management, should be assessed before investing in even the most cost-effective options.

Decision triggers to rework, top-work or rest

The three key reasons why a grower might consider reworking, top-working or resting all or a portion of a block include:

Grapevine trunk diseases

Eutypa dieback and botryosphaeria dieback are the major grapevine trunk diseases (GTD) in Australia. 

A grapevine trunk disease assessment — through a laboratory, agronomist or by following the monitoring steps in the Best Practice Management Guide: Grapevine Trunk Disease — can help determine if trunk disease is the likely cause of declining productivity. 

Where trunk disease is found, a form of reworking known as remedial surgery can remove diseased portions of the vine.

See Eutypa dieback for more information on Eutypa and trunk diseases.

Declining cordons

Productivity decline without an identified cause may be due to dead or dying cordons. Mechanical damage, such as from repeated pruning cuts, harvester damage and tight wire wrapping, can cause cordon strangulation or restricted sap flow which will gradually reduce yield.

Over time, these types of physical injuries to the cordon can interfere with a vine’s ability to transport water and nutrients, leading to uneven budburst, fewer shoots and, ultimately, lower grape production. In some cases, cordons may die back partially or entirely, resulting in gaps along the trellis and uneven vine growth.

A long-term trend (10 years or more) of declining yield and/or fruit quality is an indicator that reworking may need to be considered.

If declining cordons or trunk disease are an issue in a certain block, reworking during a period of oversupply can help align the loss of yield with a low point of demand.

Low winegrape sales price and changing consumer demands

Winegrape price fluctuations due to factors beyond growers’ control can lead to tight margins. A review of input costs, productivity, sales options and the market outlook can help decide if swapping to a grape variety that is increasingly popular with consumers or resting the vineyard for a season may be a pragmatic option.

This approach may allow growers to minimise costs and avoid the risks of overproduction during periods of low prices, ensuring that the vineyard is well-positioned to resume full production when market conditions improve.

Reworking

“Reworking refers to changing the vine structure to correct underperforming vine yield or fruit quality. It generally involves removing the top of the trunk and cordon, then training a new shoot, but it might also involve only removing and replacing the cordons.” [Options for Vineyards: Reworking, Top-grafting, Replanting or Removing, NSW DPIRD]

This can remove grapevine trunk disease and replace poorly-performing cordon arms with productive vines again. Reworking can be initiated from the trunk or cordon.

For further advice, case studies, checklists and procedures for planning, pre-preparation and post-care of reworked vines, read Options for vineyards: Reworking, Top-grafting, Replanting or Removing.

Top-working a vineyard

Top-working can enable a quick variety change without losing multiple harvests but it must be executed well to be successful.

In deciding whether it is an option, growers should consider:

• Vineyard suitability: Top-working is a major undertaking and a significant financial commitment. Consult the vineyard suitability checklist in the Options for Vineyards: Reworking, Top-grafting, Replanting or Removing guide (page 23) to determine if it is appropriate for you. The requirements are diverse, including ensuring the current variety is not viable and the new one is both suitable and saleable, that vineyard infrastructure is in good condition, vine trunks are suitable and there is high vine uniformity, access to reliable vineyard labour and that the vineyard manager has grafting knowledge. 
• Cuttings: The quality of cuttings will ‘make or break’ an investment in top-grafting. It is essential that both scion and rootstock are tested for grapevine viruses, and their combined viral compatibility determined. It is also important to understand how many cuttings are needed and at what diameter. While the general rule is to budget on two buds per cutting plus some extras for any re-grafts, it can be influenced by variety, growing season and bud size. For further insights, consult the Options for Vineyards: Reworking, Top-grafting, Replanting or Removing guide (page 23).
• Vine management after top-grafting: Frequent training of new shoots is vital and seven to 10 training passes at regular intervals are recommended. Before the growing season, develop a program to ensure labour is available during peak times. Use the Options for Vineyards: Reworking, Top-grafting, Replanting or Removing guide checklist for successful field grafting (page 25)

Important

It is critical to get source cuttings and the existing vines on which they will be grafted virus checked before starting work

Resting a vineyard

When market conditions are unfavourable, resting a vineyard can reduce expenses while keeping it in good condition so it is ready to resume production once grape prices improve.

Thorough planning can minimise costs and reduce the risk of neglect-related problems, such as dieback, pest and disease build-up and the need for extensive rework.

Some key aspects of resting a vineyard are addressed in this AWRI webinar on vineyard resting, including tips for applying a plant growth regulator (PGR) and managing irrigation.

For cost-effective vineyard resting, a PGR such as ethephon can remove inflorescences from the vine before they develop into bunches.

Research by the South Australian Research and Development Institute (SARDI) found ethephon applied at EL25 to EL27 (80% cap fall through to young berry enlargement) achieved full crop removal, followed by a return to commercial level yields the following season.

The same research found that when fruit was removed using ethephon for two consecutive seasons, irrigation could be decreased by about 70% from 7ML/ha to 2ML/ha with a slight yield penalty in the third ‘normal’ season (i.e., no ethephon and no drop in irrigation). The study was done in the Riverland with Shiraz. A report on this study will soon be available on the Wine Australia website.

In machine pruned vineyards, double-pruning (re-pruning at EL19 to EL26) is an alternative option for growers who do not want to use a PGR. However, it becomes less effective for crop removal over multiple seasons and may increase the time it takes for vines to return to full production.

Tips for using ethephon

Growers should check the current version of the ‘Dog Book’ to ensure the PGR is registered for the intended use and choose an appropriate rate of application.