Virus-Free Vineyards – The Blog

Seasonal toolkit for managing leafroll 3

March is the best time to monitor red varieties for the visual symptoms of infection from leafroll 3 virus. This year, growers have an additional tool to help with the job.

New Zealand Winegrowers’ Leafroll 3 App, launched in 2014, enables you to take a photo of leaf symptoms in your vineyard (using your smartphone’s camera) and send it to the Virus Elimination Project team for verification. The app is available for free and can be downloaded from the iPhone and Android stores.

The app also provides you with links to the popular Flickr photo library, which shows Leafroll 3 symptom expression on individual varieties, including:

  • Pinot Noir
  • Merlot
  • Cabernet Sauvignon
  • Syrah
  • Malbec

Sports and spots for survey

Assessing the level of virus infection across New Zealand vineyards is the subject of Arnaud Blouin’s doctoral research – and he’s looking for industry participation during the run-up to vintage 2015.

Arnaud, a senior staff member at Plant & Food Research Ltd in Auckland, is conducting a survey of grapevine viruses already present in the country as part of his studies at the University of Auckland. He also hopes that growers and viticulturists will contact him if they spot unusual symptoms in the vineyard during the period from February to April. 

This Sauvignon blanc leaf was tested and shown to be free of Leafroll 3 Virus despite showing typical symptoms.

Symptoms of interest include:

  • Leaf distortion, leaf spots, leaf scorch or unusual leaf colouration (early yellowing or reddening, for example)
  • Extremely low vigour
  • Unusual branching or uneven wood maturation on canes
  • Early leaf drop
  • Graft incompatibility symptoms

‘The symptoms may be an indication of infection from one or more grapevine viruses, which can be identified using laboratory diagnostics,’ observes Arnaud. ‘Some viruses might be harmless but the goal of my survey is to learn as much as possible about their presence and impact – and growers can help with that.’

Arnaud is the current recipient of New Zealand Winegrowers’ Rod Bonfiglioli Scholarship, and he is working closely with team members from the Virus Elimination Project to stop the spread of Grapevine leafroll-associated virus 3 in New Zealand vineyards. You can read more about his research in the current issue of New Zealand Winegrower magazine.

If you'd like to report unusual symptoms, you can contact Arnaud by email at  

News from home & away

As 2014 comes to a close, New Zealand Winegrowers’ Virus Elimination team members are preparing for the sixth and final vintage of the project. Once again, we will be helping participants in Hawke’s Bay and Marlborough to:

  • Identify and map the presence of Grapevine leafroll-associated virus 3 (Leafroll 3).
  • Contain and control the virus and the main vector – mealybugs – through a programme that encompasses vine removal/replants, hygiene practices and insect control.

Meanwhile, word of the project’s spectacular results has spread far beyond New Zealand shores. This post will provide a short update on our travels. First, however, we’d like to acknowledge the efforts of all the growers and viticulturists who are involved in the research and are following our best-practice guidelines – your participation has been vital to the success of the project.

South African Sojourn

Hot on the heels of submitting his PhD thesis for marking, Vaughn Bell travelled to South Africa in mid-October for a whistle-stop tour of the wine country around Stellenbosch. One of Vaughn’s PhD supervisors is also a key member of the Virus Elimination team: Professor Gerhard Pietersen (University of Pretoria). At Professor Pietersen’s invitation, Vaughn delivered two presentations to local growers in Robertson and Paarl, explaining our project’s approach and summarising his research into the relationship between leafroll disease and the mealybugs that spread the virus.

Vaughn, a scientist with The New Zealand Institute for Plant & Food Research Ltd, also had the opportunity to meet with a number of Professor Pietersen’s post-graduate virology students, and Dr Pia Addison, an entomologist at Stellenbosch University. Dr Addison’s work includes research on interactions between mealybugs and ants, and biological control in several horticultural systems.

Vaughn’s travels included a memorable visit to Vergelegen Estate, (shown in the photo above), the vineyard referred to by Professor Pietersen during his presentations. Set within a truly remarkable landscape, this beautiful vineyard is now virtually free of leafroll virus, thanks to the efforts of Professor Pietersen and the wonderful support he has received from Andre and Maritza van Rensburgh. Andre, the winemaker, and Maritza, the viticulturist, are passionate about the place they call home and the wine they produce. Vaughn commented on what a pleasure it was to have met such passionate and interesting people.

Session in Southern France

Later this month, project manager Nick Hoskins will make a presentation to growers at the Second Conference on Wines from the Southwest of France. Nick will be speaking on ‘Leafroll in New Zealand – Prevention of an Epidemic.’

The conference will focus on new threats to regional vineyards caused by viral diseases and pests, and will be held in Toulouse, the capital of the Midi-Pyrénées region. Nick has been invited to speak by the Southwest chapter of the French Vine and Wine Institute (IFV), which is co-organiser of the event with the regional association of winegrowers, winemakers and winesellers.

Dr Simon Hooker, NZ Winegrowers’ General Manager Research, will be travelling to France with Nick, and, in addition to their participation in the conference, they will visit the region and meet with French researchers at the IFV.

International collaboration has been a hallmark of the Virus Elimination Project right from the start, and we have benefited tremendously from the insight and expertise offered by Professor Pietersen. It’s now clear that sharing our New Zealand experiences is of interest to growers in other countries. We hope that our presentations will help viticulturists develop management strategies for their own vineyards.

About

Welcome! This blog is maintained by members of the Virus Elimination Project, a New Zealand Winegrowers' Research Project that is co-funded by the Ministry for Primary Industries (Sustainable Farming Fund).

The Virus Elimination Project has three main objectives:

  1. Identify and map the presence and/or spread of Grapevine Leafroll-associated Virus 3 (Leafroll 3) in participating vineyards in New Zealand.
  2. Contain and control Leafroll 3 virus and the main vector – mealybugs – through a programme that comprises vine removal/replants, hygiene practices and insect control.
  3. Develop “best practice” guidelines for New Zealand Winegrowers, with the long-term goal of maintaining virus-free vineyards.

Control and management of Leafroll 3 is a community issue. That’s why the project trains growers to identify leafroll virus, map, treat, and remove infected vines on an area-wide basis in tandem with effective control of mealybugs. We welcome your comments and questions on this blog.

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