Impact of yeast derivatives to increase the phenolic maturity and aroma intensity of wine

Grapevine downy mildew (GDM), caused by the oomycete Plasmopara viticola, is one of the most destructive diseases of Vitis vinifera worldwide. All V. vinifera cultivars are susceptible to P. viticola infection, and epidemics can spread across an entire vineyard within a matter of weeks. Severe outbreaks cause substantial reductions in yield and fruit quality. Tracking GDM spread by manual scouting is time-consuming and unfeasible over large spatial extents.

The aromatic profile of a wine is the result of volatile molecules present in grapes (varietal or primary aromas) and those produced during the winemaking process of fermentation (secondary aromas) and during wine aging (tertiary aromas).

In Washington State, the majority of winegrape (Vitis vinifera) vineyards are planted to their own roots. This practice is possible due to the lack of established phylloxera populations, and is preferred due to the ease of retraining after damaging winter cold events. However, own-rooted V. vinifera is generally susceptible to most plant parasitic nematodes that attack grape. In Washington State, management of nematodes is dominated by preplant soil fumigation. One practice that may mitigate economic loss due to nematodes is the adoption of nematode-“resistant” rootstocks.

Climate change is increasing the frequency and severity of environmental hazards (e.g., prolonged drought), and even non-extreme climate events (e.g., a period of slightly warmer temperatures) can lead to extreme impacts when they occur simultaneously with other (non-extreme) events.

Historical records of grapevine phenology have been collected over decades throughout different winegrowing regions. These records have demonstrated advances in key developmental stages such as budburst, flowering and veraison because of increased temperatures due to climate change.