A new project aims to develop a practical ‘how to’ guide for vineyard owners and their staff to detect and manage three key viral pathogens of grapevines – grapevine leafroll-associated virus 1 (GLRaV-1), GLRaV-3, and GVA, which causes Shiraz Disease
Viruses are becoming increasingly widespread in Australian vineyards, with affected producers noticing discoloured leaves, a symptom of virus infection, on their vines in autumn.
The project draws on research that has already been undertaken in Australia and elsewhere in the world, including initial work by Treasury Wine Estates.
‘The goal is to provide practical information on just about any aspect of these pathogens so that users can implement or adapt responses to the viruses, the vectors, and how they monitor and manage them’, said Dr Vaughn Bell, Senior Scientist, the New Zealand Institute for Plant and Food Research (NZ).
Grapevine Leafroll- and Shiraz Disease are transmitted via pathogens by grafting infected plant material and by insects, including multiple species of mealybugs and soft scale insects. Viruses can reduce vine yield, negatively alter fruit quality parameters, and ultimately lower wine quality. There is no cure, so if grapevines are to be protected for the long term, the best option is to remove (or rogue) infected vines.
Vaughn said having a NZ perspective on the project was important.
He said NZ had implemented a Virus Elimination response to GLRaV-3 in 2008, and the country had considerable experience and success in tackling a viral pathogen at the vineyard level and at a regional level.
‘NZ has experience of those practical responses that worked for us in our environment. We also have knowledge about what practices didn’t work; sometimes that experience extends to offering explanations as to why they didn’t work.’
‘In NZ, the major viral pathogen of grapevines is GLRaV-3. However, despite apparently fewer viral pathogens in NZ compared to Australia, many of the management responses to GLRaV-3 are also applicable to GLRaV-1 and Shiraz Disease – because all three pathogens are transmitted by grafting and by insects.’
‘Through practical implementation of Virus Elimination in NZ we can begin to offer advice to Australia about what should be contemplated in Australian vineyards and steps that should or could be implemented.’
Treasury Wine Estates Viticulture Manager, Ben Harris, said the project was critical in furthering initial work by Treasury on establishing sector best practice standards, raising awareness and identifying knowledge gaps requiring further R&D and investment.
He said everyone in the wine sector had a role to play in being on guard for viruses.
‘Viruses can limit the full potential of a vineyard if they find their way in. It’s critical everyone understands the potential impact of viruses and is aware of best practice, from sourcing planting material, to vineyard development, to protecting important heritage vineyards. We’re really supportive of this project’.