Effects of Different Sulfur Dioxide Pads on Botrytis Mold in ‘Italia’ Table Grapes under Cold Storage

Abstract

‘Italia’ grape is one of the most important table grape cultivars grown worldwide. Gray mold, caused by Botrytis cinerea Pers. Fr., is one of the most important causes of postharvest decay of table grapes, and the control of this disease is very difficult because postharvest treatments with synthetic fungicides are not allowed in many countries. The objective of this study was to compare different types of pads releasing different doses of SO2 during cold storage to control gray mold in ‘Italia’ table grapes grown under subtropical conditions. Grape bunches were harvested from a commercial field trained on an overhead trellis located at Cambira, state of Parana (PR), South Brazil. The grapes were packed into carton boxes (capacity, 4.5 kg) and subjected to the following SO2 pad treatments (Uvasys®, Cape Town, South Africa) under cold storage (1.0 ± 1 °C) for 50 days: (i) Control; (ii) SO2 slow release pad; (iii) SO2 dual release pad; (iv) SO2 dual release–fast reduced pad; (v) SO2 slow release pad with grapes inoculated with B. cinerea suspension; (vi) SO2 dual release pad with grapes inoculated with B. cinerea suspension; and (vii) SO2 dual release-fast reduced pad with grapes inoculated with B. cinerea suspension. After cold storage, the grape boxes were maintained for 7 days at room temperature (25 °C). The incidence of gray mold on the grapes, firmness, shattered berries, stem browning, as well as other physicochemical variables, such as bunch mass, bunch mass loss, skin color, soluble solids (SS), titratable acidity (TA) and SS/TA were evaluated. Both SO2 dual release pads were highly efficient in preventing the incidence of gray mold in ‘Italia’ grapes packed in clamshells during the 50-day period of cold storage and at room temperature, even with Botrytis-inoculated berries. The SO2 slow release pad showed lower efficiency, but was higher than the control. The SO2 dual release pad treatments provided the best results with respect to stem browning scores (fresh and green stems) during cold storage, and no differences were observed among the treatments with respect to the other physicochemical evaluations.

Postharvest Preservation of the New Hybrid Seedless Grape, ‘BRS Isis’, Grown Under the Double-Cropping a Year System in a Subtropical Area

“…Considering these aspects, combined with cold storage, the SO 2 -generating pads can be used as a tool to control the gray mold of 'BRS Isis' seedless grapes, at least for a period of 50 days. A similar performance has also been observed in rthe maximum reduction of the disease incidence of 'BRS Vitoria' and 'Italia' table grapes at 50 days of cold storage and at seven days at 22 ± 2 • C, respectively [17,22].…”

“…Grapes were harvested at full ripeness when the content of the berry soluble solids reached around 14 • Brix [21,22]. Bunches were selected free from any disorders and standardized according to bunch shape, size, and mass, and subjected to the following treatments into a cold chamber at 1 ± 1 • C: (i) Control; (ii) SO 2 -generating pad; (iii) control with bunches inoculated with B. cinerea suspension; (iv) SO 2 -generating pad with bunches inoculated with B. cinerea suspension.…”

Control of Gray Mold on Clamshell-Packaged ‘Benitaka’ Table Grapes Using Sulphur Dioxide Pads and Perforated Liners

“…On the other hand, despite emitting a constant amount of gas from the beginning to the end of the storage period, the slow release pad containing 7 g of a.i. did not lead to a complete absence of gray mold in the grapes, which can also be influenced by the natural occurrence of the fungus and the types of packaging employed [29][30][31]. The different plastic liners evaluated had no influence on this feature in the periods evaluated, however, it was found that the bunches submitted to a combination of factors displayed a lower mean incidence of gray mold compared to those in the additional treatment, which confirmed the need for SO 2 -generating pads in the control of gray mold of 'Benitaka' table grapes during cold storage [4].…”

Sulphur Dioxide Pads Can Reduce Gray Mold While Maintaining the Quality of Clamshell-Packaged ‘BRS Nubia’ Seeded Table Grapes Grown under Protected Cultivation

“…As a postharvest treatment, the use of SO 2 -generating pads during cold storage is commercially implemented to manage gray mold of table grapes [11]. Dual release SO 2 generators inside the boxes have been commonly used for grape storage and transportation for periods up to two months [7,12,13]. Grape exporters are always worried about limited long-distance transport of fresh grapes, especially when intensive production occurs in subtropical areas where two crops per year is possible.…”