Evolution of fungicide residues in pruned vine-shoots

Pruned vine-shoots used as wine additives have proven to be a useful tool for improving and differentiating wines. This is because they accumulate substances from the plant itself, which later, as a result of the toasting process, express their greatest oenological potential. However, vine being one of the crops subject to the most phytosanitary treatments, including fungicides in particular, it can be assumed that their residues will accumulate in the vine-shoots and pass into the wine. The aim of this study was to determine the content in pruned vine-shoots of four of the main fungicides applied in the vineyard in Spain: trifloxystrobin, boscalid, kresoxim-methyl and penconazole. In order to do so, a HPLC-MS/MS method was developed, which showed high reliability given its adequate validation parameters. The method was linear for the concentration range studied, LOD was 0.003 mg/kg and LOQ was 0.01 mg/kg, which comply with the control criteria. The evolution of residues in vine-shoots complying with critical agricultural practices and good agricultural practices was monitored at 1, 3 and 6 months of storage after pruning and, in the latter case, after being subjected to a toasting process. The dissipation of all the residues was demonstrated to be affected by storage duration and toasting. It was confirmed that converting vine-shoots into oenological additives for wines will not pose a risk to the consumer if good agricultural practices are applied.