Antifungal activity of Salvia officinalis extract against Plasmopara viticola

Plant extracts may represent an alternative to chemical fungicides. The efficacy against grapevine downy mildew of sage (Salvia officinalis) alcoholic extract, its persistence and rain fastness were evaluated. When applied on artificially inoculated potted grapevine plants under greenhouse controlled conditions the sage extract provided high control of disease, whereas in field experiments the efficacy was lower. The residual activity (persistence) of the sage extract is good, but it is easily washed away by rain. In facts even 10 mm of simulated rain significantly reduce its control activity. With a suitable formulation, able to reduce the rain fastness, this sage extract could be a promising control tool for organic viticulture.