The efficacy of a range of sulfur dioxide generating pads against Botrytis cinerea infection and on out-turn quality of Calmeria table grapes.

A postharvest storage trial was undertaken to test the efficacy of 3 brands of dual-release sulfur dioxide (SO2) generating pads against Botrytis cinerea in stored table grapes (Vitis vinifera cv. Calmeria) and to determine if there were any detrimental effects (bleaching, SO2 residues) of the pads on table grape quality. The UVAGAS and UVAS Quality Grape Guard pads slowed decay development and the spread of botrytis rot, prevented naturally occurring infections, and retained stem freshness better than the SYS pad which is commonly used in the Swan Hill area. A properly working SO2 pad placed in the top of a 10-kg box was sufficient to control botrytis rot in table grapes even when moderate levels of initial inoculum were present. The results indicate that increased SO2 residues in fruit and bleaching of berries over time are more likely with increasing damage caused by B. cinerea. After 10 weeks, both inoculated and non-inoculated grapes stored with UVAGAS or UVAS pads were in sound and commercially acceptable condition. In contrast, SYS SO2 pads did not provide acceptable control of B. cinerea in Calmeria grapes.