Decay of fungicide residues during vinification of white grapes harvested after the application of some new active substances against downy mildew

Abstract: Cyazofamid, famoxadone, mandipropamid and valifenalate are new fungicides recently proposed to control downy mildew (Plasmopara viticola) in vines. In this study, three of them were applied in an experimental vineyard producing white grapes (Vitis vinifera cv. Godello) as commercial formulations: Mildicut (2.5% cyazofamid), Equation Pro (22.5% famoxadone+30% cymoxanil) and IR-5885 (6% valifenalate+60% mancozeb), meanwhile mandipropamid was directly applied as an active substance. The last treatments to control this disease were made out under critical agricultural practices, without obeying the preharvest interval. Besides the above products, the control of powdery mildew (Erisiphe necator) and grey mould (Botrytis cinerea) was made by employing standard commercial formulations. Once treated white grapes were harvested, the fate of all these fungicides from vine to wine was studied. Residues of cyazofamid, famoxadone and valifenalate in grapes were higher than their EU MRL, except for mandipropamid. The white wine-making process allowed the dissipation of fungicide residues in high percentages (ca. 95%), except for valifenalate that remained in wine at 32%. [ABSTRACT FROM AUTHOR]