Pre-Harvest Bagging of Table Grapes Reduces Accumulations of Agrochemical Residues and Increases Fruit Quality

Abstract

Since ancient times, table grapes (Vitis vinifera L.) have been one of the most important fruit crops from the standpoint both of the producer (regional economics) and the consumer (healthy eating). In recent decades, much effort has been devoted to the development of this crop in order to improve fruit quality and yield; however, these advances have also entailed considerable increases in the use of agrochemicals. Unfortunately, as is now coming to light, the increased agrochemical use has had deleterious effects on the environment and has also had significant negative effects on human health and wellbeing. Our research investigates the effects of pre-harvest fruit bagging on key fruit quality traits and also on the accumulation of agrochemical residues in the fruit. Two prevalent white table grape cultivars were used, ‘Italia’ (late ripening) and ‘Vittoria’ (early ripening). They were bagged with three different materials: (1) paper, (2) parchment (a cellulose-based material), and (3) a non-woven fabric (felted polypropylene fibers). The bags were placed on grape clusters at phenological state BBCH 75 until harvest, and the bagged clusters were then compared with the unbagged control clusters. Qualitative traits and agrochemical residuals were assessed at harvest for two consecutive years, 2021 and 2022). The results show that the parchment protection bags positively affected some key fruit quality traits, with bigger and better-colored berries than the unbagged controls. Compared with the unbagged controls, all bagging treatments greatly reduced the levels of agrochemical residues, analyzed using GC-MS/MS and HPLC-MS/MS. For cv. ‘Italia’, in 2021 residues fell from 0.733 mg/kg (unbagged control) to 0.006 mg/kg (bagged), and in 2022 from 0.201 mg/kg (unbagged control) to 0.008 mg/kg (bagged); for cv. ‘Vittoria’, in 2021 residues fell from 0.201 mg/kg (unbagged control) to 0.008 mg/kg (bagged), and in 2022 from 0.077 mg/kg (unbagged control) to 0.046 mg/kg (bagged). The study shows the benefits of pre-harvest fruit bagging on grape berry quality and underscores the pivotal role bags can play in minimizing agrochemical residue accumulations on the fruit. The study marks the taking of a crucial step towards more sustainable and safer practices in the table grape production industry.