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

Abstract

The use of vented clamshells has become popular in the packaging of grapes for local and international markets. The aim of this study is to evaluate the postharvest preservation of ‘Benitaka’ table grapes individually packaged in vented clamshells using different types of SO2-generating pads and perforated plastic liners during cold storage. A completely randomized design with four replications in a two-factor arrangement with an additional treatment [(4 × 3) + 1] was used. The trials were carried out under two situations: Artificial or natural infections with Botrytis cinerea, which is the causal agent of gray mold on table grapes. The incidence of gray mold, shattered berries, and stem browning were evaluated at 30 and 45 days of cold storage at 1 ± 1 °C and 3 days of shelf-life at 22 ± 1 °C after the period of cold storage. Mass loss and berry firmness were also examined at the end of the cold storage period. The use of dual-release SO2-generating pads containing 5 or 8 g of a.i. and slow-release pads with 7 g of a.i. was effective in controlling the incidence of gray mold in grapes packaged in vented clamshells and kept under cold storage for up to 45 days. Under these storage conditions, perforated plastic liners with 0.3% ventilation area or micro-perforated liners with 1.0% ventilation area reduced the percentage of mass loss and shattered berries.

Control of postharvest gray mold of ‘BRS Nubia’ table grape under cold storage

“…The use of SO 2 -generating pads was shown to be a good strategy to control gray mold when 'BRS Nubia' table grapes are submitted to cold storage, with satisfactory results at the end of 30 days. These results agree with those reported by Ahmed et al (2019), Chaves et al (2019), and Youssef et al (2015) for some table grape cultivars. Depending on grape cultivar, the results are even better, as those obtained for 'Red Globe' grapes, in which SO 2 -generating pads can control the disease up to a 4-month period under cold storage (Ozkaya, Dundar, & Özdemir, 2008).…”

“…However, the control of gray mold is very difficult through synthetic fungicides, and due to safety reasons, they have been banished in many countries (Youssef et al, 2015). Thus, some environmentally friendly strategies are recommended to control gray mold in table grapes during postharvest, such as treatments with salt solutions (Youssef & Roberto, 2014), SO 2generating pads, and cold storage (Ahmed et al, 2019;Chaves et al, 2019;Youssef et al, 2015).…”

“…Bunches were submitted to the following treatments: cold storage at 2 ºC (control); cold storage at 2 ºC with an SO 2 -generating pad; cold storage at 2 ºC and inoculated with a B. cinerea mycelium suspension; and cold storage at 2 ºC with an SO 2 -generating pad and inoculated with a B. cinerea mycelium suspension. The bunches that were inoculated with B. cinerea mycelium suspension were previously disinfested according to Chaves et al (2019). For SO 2 treatments, one generator pad measuring 13 cm × 23 cm per box provided with fast and slow release phases of sodium metabisulfite (Na 2 S 2 O 5 ), 98% (Matesa ® , Grapeguard, Chile) was used during the cold storage period and subsequently removed at the beginning of shelf life.…”

SO2-generating pads reduce gray mold in clamshell-packaged ‘Rubi’ table grapes grown under a two-cropping per year system

“…For this reason, the integration of management in the field with phytosanitary treatments and the use of appropriate packaging during cold storage are the commercial strategies that most contribute to reducing losses and controlling postharvest diseases (Palou et al, 2002;Droby & Lichter, 2004;Liguori, Sortino, Pasquale, & Inglese, 2015;Salem, Youssef, & Sanzani, 2016). Among attempts to reduce the incidence of B. cinerea postharvest in different grape cultivars, the use of SO 2 -generating pads during cold storage demonstrated good performance (Ahmed et al, 2018;Domingues et al, 2018;Chaves et al, 2019;Youssef, Chaves, Mühlbeier, & Roberto, 2020), mainly due to its efficiency, ease of use, affordable cost and low health risk when compared to fungicides (Melgarejo-Flores et al, 2013). This gas, in addition to inhibiting the development of microorganisms, has antioxidant action, influencing the physiological processes of the bunch itself, for example, maintaining the rachis or stem green and fresh (Muñoz, Benato, Sigrist, Oliveira, & Corrêa, 2000;Zoffoli & Latorre, 2011).…”

“…The climate of this area, according to the classification proposed by Köppen, is subtropical Cfa type, with an average annual precipitation of 1,633.5 mm, minimum average temperature of 18 ºC and maximum of 22 ºC (Instituto das Águas do Paraná [IAP], 2017). The area was selected for having a recurrent history of gray mold (Ahmed et al, 2018;Chaves et al, 2019).…”