A systemic approach to grapevine decline diagnosed using three key indicators: plant mortality, yield loss and vigour decrease

Grapevine decline, a major global viticulture issue, is defined as multi-year decrease in vine productivity and/or increase mortality. Although grapevine trunk diseases are one of the most-studied causes, decline multifactorial and associated with more than 70 factors, including abiotic biotic hazards. With so many factors to consider, phenomenon difficult understand, especially for winegrowers. Our study aims make it easier determine assess by focusing on three key indicators: yield, mortality vegetative vigour. We investigated relationships between these indicators from both temporal spatial perspective propose set diagnostic indicators. Thus, we conducted winegrowers’ survey, an historical analysis field measurements abovementioned plot networks French winegrowing regions (see graphical abstract): Bordeaux, Cognac Languedoc. found that farmers’ perceptions were consistent objective characterisation based in-field progressively spread over years, neither survey nor showed direct link yield loss. Rather, large yearly fluctuations which did not systematically time, account this finding. As result, rate normalised difference vegetation index (NDVI) shown be earlier loss (yield achievement ratio, YAR). performed overall data deepen our understanding variety declining situations underlying environmental management contributing decline. Finally, two ground-based NDVI image-analysis methodology using aerial photographs proposed easy-to-obtain linearly correlated YAR rate. This provides better promising tools early diagnosis