Virus-Free Vineyards – The BlogFeed for this Blog
Was the 18th of March the busiest day this year for monitoring symptom expression of Leafroll 3 Virus in red varieties? The reason we ask is that, on that day, our Flickr photo library clocked up another 1259 views.
Recognising the symptoms of infection takes some practice, and the Flickr library was created by project team members as a visual aid to illustrate Leafroll 3 expression on individual red varieties, including:
The photos, plus other sets showing magnesium deficiency and the difficulty of spotting symptoms accurately on Sauvignon Blanc, have proven to be a popular tool for Leafroll 3 management. Flickr photos are easily viewed on mobile devices, and a number of vineyard managers have bookmarked the URL address on their smart phones and tablet computers so that they can access the visual references as they walk along the rows in the vineyard.
We created the Flickr photo sets in February 2013, and the library received nearly 5000 views through to the end of December last year. Clearly, however, word has since spread about the usefulness of this resource. In the past three months alone, the library has received an additional 4700 views – and we’re quietly confident that total views will sail past the 10,000 mark before vintage is done and dusted for 2014.
One of the goals we’ve set for the Virus Elimination Project is to make it easier for growers to access information in a variety of ways. Our foray into Flickr has proven to be especially popular, and it’s likely to have staying power. We expect to see the trend repeated in subsequent years when vineyard managers once again return to symptom monitoring before harvest.
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Unlike red varieties, which reliably express visual symptoms of Leafroll 3 infections, white varieties present an additional challenge to vineyard managers’ attempts to control the spread of the virus. While some leaves on some white-variety grapevines may express similar visual symptoms, they are not a reliable indicator of infection – and many vines will show no symptoms at all.
Sauvignon Blanc tested 'positive' for Leafroll 3
Sauvignon Blanc tested 'negative' for Leafroll 3
Instead, statistical screening – involving the collection of leaf or cane samples and laboratory ELISA testing – is used to provide information about the percentage of infection in a block.
‘ELISA’ is short for ‘Enzyme-linked ImmunoSorbent Assay’ – a type of laboratory test that uses the reaction of an antiserum (antibody) to verify the presence of a disease, including Leafroll 3. ELISA tests are accurate, fast and relatively inexpensive compared with other testing methods used on grapevines.
Results from statistical screening provide useful information related to the disease status of a vineyard, and the method is used increasingly in connection with purchasing decisions.
New Zealand Winegrowers’ Virus Elimination Project has prepared a new fact sheet, outlining the steps involved in testing white varieties for Leafroll 3. The instructions are easy to understand, and links are provided to each of the laboratories accredited by IANZ for the testing procedure.
You can download ‘Testing white varieties for Leafroll 3’ from this page – look for the box entitled ‘Fact Sheets’ on the lower right.
We have also updated our fact sheets on ‘Leafroll symptoms on red varieties’ and ‘Vine removal on Leafroll 3’ to include guidelines developed from data analysed by Vaughn Bell, a scientist at Plant & Food Research and a key member of our project.
The time for monitoring visual symptoms of Leafroll 3 on red varieties is now. Our Flickr photo library, showing symptoms on individual red varieties (Cabernet Sauvignon, Malbec, Merlot, Pinot Noir and Syrah) has received more than 7,000 unique views to date - a number that's literally growing every day. The library provides a helpful catalogue of visual symptoms ranging from individual leaves to entire vines, and we hope many more of you will access this tool during the present monitoring period.
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New Zealand Winegrowers’ Virus Elimination Project has completed a seven-part video series, outlining the key steps to controlling Leafroll 3 Virus in vineyards.
The series, presented by project manager Nick Hoskins, covers essential topics including:
- Early-season mealybug control
- Symptom monitoring on red varieties
- Mealybug monitoring
- Removal of infected vines
- How to plant and treat replacement vines
The videos have been posted on the members area of NZW’s YouTube channel and can be accessed here after signing in.
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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:
- Identify and map the presence and/or spread of Grapevine Leafroll-associated Virus 3 (Leafroll 3) in participating vineyards in New Zealand.
- Contain and control Leafroll 3 virus and the main vector – mealybugs – through a programme that comprises vine removal/replants, hygiene practices and insect control.
- 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.
- What is GLRaV-3?
- Leafroll symptoms on red varieties
- What is the Virus Elimination Project?
- What are the commercial costs associated with GLRaV-3?
- Mealybug control for cropping vines
- Mealybugs – knowing the pest
- How to look for mealybugs
- Vineyard hygiene & Leafroll 3
- Vine removal and Leafroll 3
- Vine establishment for replants
- Mapping Leafroll 3
- Pre-harvest mealybug monitoring
- Testing white varieties for Leafroll 3