Effects of Growing Areas, Pruning Wound Protection Products and Phenological Stage on the Stilbene Composition of Grapevine (Vitis vinifera L.) Canes.

Applying plant protection products (PPP) on grapevine pruning wounds is a viticultural practice used to mitigate the spread of Grapevine Trunk Diseases, which are posing serious economic losses in the vine-wine industry. However, PPP impact on woody tissues remains unclear. Our study, conducted in two European vineyards investigated the effects of Cuprocol®, Tessior®, Esquive® and Bentogran® on stilbenes, in canes of Cabernet sauvignon and Syrah, at three phenological stages. Main stilbenes, quantified by HPLC-UV-DAD and identified by HPLC-ESI/MS, included E-resveratrol, E-ɛ-viniferin, E-piceatannol and E-polydatin. Canes exhibited varying proportions of individual stilbenes, reflecting differences based on climatic conditions and phenological phases, rather than on the application of specific PPP. Vines grown in cool-climate conditions exhibited higher levels of E-resveratrol, whereas vines from Mediterranean climate area of E-ɛ-viniferin. We also observed divergences in the accumulation trend of wood stilbenes throughout the season in the canes collected in the two different growing areas.