Responses to pathogen threats are higher in biodynamic vines

Wednesday February 27 2019 by Vitisphere

 Biodynamic vines have more yellow foliage (left) than conventional vines (right), according to Alsace researchers. Biodynamic vines have more yellow foliage (left) than conventional vines (right), according to Alsace researchers. - Photo credit : INRA Colmar

Natural defences are higher in vines farmed biodynamically, whatever the climate and pathogen pressure”, claims Jean Masson, research director at the Colmar national agronomic research institute (INRA). He draws his conclusion from results thrown up by monitoring the levels of secondary metabolites and immunity gene expression from 2014 to 2017 in fourteen plots of Pinot Noir vines totalling 30 hectares managed by 8 conventional and 3 biodynamic winegrowers.

Published in Scientific Reports, the study ascertained that the downy mildew and powdery mildew load of the vines monitored was higher for those farmed biodynamically than those using conventional vineyard management (respectively 51% and 22% of infected plants on average from 2014 to 2017). But “whatever the case, none of the collected leaves showed any visible symptoms, such as a powdery surface or oil stains. Both systems were able to stop the infection”, said the study, which is based on early molecular detection of downy and powdery mildew.

Although the leaves are unharmed, they do not look the same depending on vineyard management methods. Conventional winegrowers often like to make fun of the yellowish and diseased appearance of biodynamic foliage. After analysing the composition of the leaves from 2015 to 2017, the scientists observed that chlorophyll levels were higher on conventional vines (reflecting better photosynthetic activity), while anthocyanins and flavonols were higher for biodynamic vines (indicating a response to stress, either climatic or fungal).

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