A new approach to detecting Phylloxera

12/06/2015

Testing for Phylloxera is about to move into the 21st century and become a lot more accessible.

The Phylloxera and Grape Industry Board of SA (PGIBSA) and six research partners are making great strides with a project to develop sampling strategies for sensitive, accurate and cost-effective detection of Phylloxera that can be used in any vineyard by almost anyone. These strategies can then be used for Phylloxera management and quantifying area freedom status.

It’s something CEO Alan Nankivell says is desperately needed.

‘The technology used for identifying Phylloxera in vineyards hasn’t changed since the 19th century’, he said.

‘It’s essentially a shovel and a magnifying glass and you go looking, based largely on sites of low vigour. What’s the problem here? Could it be Phylloxera?’

That’s not to deny the value of aerial surveying, which has been used by the PGIBSA in recent years to assist in identifying potential trouble spots. The problem is that it is costly and you still need to confirm trouble spots with a shovel and magnifying glass. When Phylloxera was found in the Yarra Valley in 2006, aerial surveying didn’t identify the problem before or after it had been found at ground level.

The PGIBSA decided it had to find a better way and Mr Nankivell came across a possible answer during discussions with the South Australian Research & Development Institute (SARDI). Back in 2003, SARDI and Department of Primary Industries (DPI) Victoria jointly developed a quantitative DNA-based assay for the specific detection of Phylloxera. However, work to determine its applicability for Phylloxera management was not explored further.

The current four-year project – funded by Wine Australia and the Plant Biosecurity CRC – was set up in early 2013 to leverage this earlier work and develop a vineyard sampling protocol to collect soil samples that could be analysed through the DNA assay. In its third year, over 500 soil samples have been collected using a simple corer from trial sites in the Yarra Valley, King Valley and Rutherglen, with samples being analysed back at SARDI.

‘The first step was to determine how to handle the soil samples collected to ensure that we were not affecting the ability of the DNA assay to detect the presence or absence of Phylloxera in the soil sample. Recommendations were made on the time between sampling and analysis and storage temperature’, Mr Nankivell said.

‘Once we knew how to handle the soil samples, we needed to work out how best to sample a vineyard to determine the presence or absence of Phylloxera. We tested at all times of the year, at different depths and locations relative to the trunk and dripper, and we found Phylloxera every time of the year at statistically significant levels’.

With a preliminary sampling strategy developed, work continues to validate and fine tune the findings to ensure a robust protocol for use by industry.

‘It is our intention that, by the end of this year, we will have protocols worked out and have in train the process of getting endorsement for the concept and the protocols at a national level’, Mr Nankivell said. ‘The following year, the last of the project, will be focused on ensuring adoption by the sector’.

The potential is enormous – not just to find where Phylloxera is, but to keep checking that areas declared Phylloxera-free remain so. Mr Nankivell envisages a time when vineyard operators will be equipped not just to take soil samples, but to do the testing themselves.

Parties involved in this collaborative project are Wine Australia, Plant Biosecurity CRC, Biosecurity SA, SARDI, the Department of Economic Development, Jobs, Transport and Resources (formerly DPI Vic), DPI NSW, and the University of Adelaide with support from Rho Envirometrics.

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