Our Wine Grape Knowledge

This past season has seen some of the best flowering conditions and fruit-set, resulting in record yields across most of the country. The result of this is that growers are faced with two unique considerations for future vine health.

• Firstly, an excessive yield will drain vine resources, and depleted energy levels must be restored prior to dormancy. Next season’s crop requires vines to have had adequate time post-harvest to store carbohydrates, plus other essential nutrients. Adequate water must also be available to vines for this process to occur. If soil conditions post-harvest were dry, then nitrogen uptake will have been compromised and affects not only early growth next season but also bud development for the 2026-27 season. Careful decisions must be made during pruning to set the crop at an appropriate level.
• Secondly, due to the excess yields, many Sauvignon Blanc blocks have not been picked. It is vital to remove any fruit left on the vine, as this triggers preparation for dormancy and storage of resources for early next season, as detailed above.
  If pruning is starting early, target blocks that were harvested earlier during vintage. Pruning is a high-risk period for a range of wood-infecting trunk diseases such as Eutypa lata and Botryspheria stevensii to develop. It’s essential to protect wounds adequately to reduce this risk. Be aware that sap may still flow if leaves are still present on vines and conditions are mild. In this case, consider using a spray-on wound treatment such as Gelseal Ultra®. This is a good time-saving option and, when applied correctly, has been shown to be more effective as a wound protectant than poorly applied pruning protectant especially when sap is flowing. Alternatively, wait until sap flow has ceased before applying a high-quality pruning protectant such as PruneTec® or Greenseal Ultra®.

Start soil tests in June.

• Continue post-harvest nutrient applications during May when vine roots flush.
• Ensure irrigation to allow essential nitrogen uptake and carbohydrate storage.
• Stimulate root activity with a late season biological activator such as Valagro Viva, either alone or in conjunction with BioStart Mycorrcin.
  
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