CSU Research: Measuring bunch rot impact on wine quality

13 MARCH 2019

CSU Research: Measuring bunch rot impact on wine quality

NWGIC research funded by Wine Australia aims to determine thresholds for bunch rot contamination.

  • Bunch rot causes economic losses to the wine industry worldwide
  • The research will provide important information for growers and winemakers

While the winegrape harvest accelerates across Australia, research at the National Wine and Grape Industry Centre (NWGIC) is arming grapegrowers and winemakers with increased knowledge about how bunch rot can impact a final wine – and how much is too much.

Led by Charles Sturt University (CSU) Professor Chris Steel, the research – funded by Wine Australia – aims to determine thresholds for bunch rot contamination, building on an earlier project that examined Botrytis or grey mould contamination of Chardonnay grapes in 2016.

“Bunch rot, or fungal rot of wine grapes, is a worldwide problem, particularly when rain falls close to harvest,” said Professor Steel.

“Bunch rots reduce yield and can impact on wine quality by producing off flavours and taints. Growers have to decide when and if they harvest impacted fruit, and at the winery it can lead to the downgrading or possible rejection of fruit.

“This project will determine the thresholds for bunch rot contamination that can be tasted in wine, and provide grapegrowers and winemakers with tools to handle fruit when these thresholds are exceeded.”

For this vintage, the new research will be extended to include Cabernet Sauvignon grapes.

“Aside from continuing to evaluate ergosterol as a measure of fungal contamination, we will also look at other techniques including measuring gluconic acid and loop-mediated isothermal amplification (LAMP), a molecular biology based technique for detecting Botrytis in grapes,” Professor Steel said.

Wine Australia General Manager of Research, Development and Extension Dr Liz Waters said, “Bunch rots can be a significant cost impact on grapegrowers and winemakers. This project is exciting because it will help us determine how much bunch rot is too much, so that an objective measure can be set to assist growers and winemakers in their decisions at harvest.”

The NWGIC is an alliance between CSU, the NSW Department of Primary Industries and the NSW Wine Industry Association.


About Wine Australia

Wine Australia supports a competitive wine sector by investing in research, development and extension (RD&E), growing domestic and international markets, protecting the reputation of Australian wine and administering the Export and Regional Wine Support Package.

Wine Australia is an Australian Commonwealth Government statutory authority, established under the Wine Australia Act 2013, and funded by grape growers and winemakers through levies and user-pays charges and the Australian Government, which provides matching funding for RD&E investments.

Media Note:

Media note: Professor Chris Steel is based at the National Wine and Grape Industry Centre at CSU in Wagga Wagga, to arrange interviews contact NWGIC communications officer Emily Malone 0439 552 385 or emalone@csu.edu.au

Read more about the recently completed project ‘Determination of thresholds for bunch rot contamination of grapes and techniques to ameliorate associated fungal taints’ in Wine Australia’s R,D&E News here https://www.wineaustralia.com/au/news/articles/fungal-rot-under-the-microscope

Information on Wine Australia’s research program can be obtained from Hannah Bentley (hannah.bentley@wineaustralia.com or 0428 930 865).

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Wagga Wagga Agricultural Science NWGIC Research Science