Exploring Novel Plant Defence Stimulators for Reducing Downy Mildew (Plasmopara viticola) in Grapevines in Brazil

In older vineyards, copper concentrations from prolonged use of copper-based fungicides can build up in the soil, harming soil life, plants, and sometimes local aquatic life due to run-off. Copper levels of up to 496 mg/kg of soil have been found in vineyards in Europe and over 1,800 mg/kg in vineyards in Brazil, whereas the level that adversely affects earthworms has been demonstrated to be 45 mg Cu/kg of soil. In 2019, European law changed to dramatically reduce the allowed amount of copper used in viticulture to 4 kg/Ha, averaged over 7 years, and so it is important to find an alternative strategy for the control of downy mildew, which can otherwise devastate a grape crop. This is particularly important for organic viticulture, which currently has no alternatives