Decay Control and Chemical Injury of Table Grapes Packed in Export Chests

¹ Department of Viticulture and Enology, University of California, Davis.
² Department of Agricultural Engineering, University of California, Davis.

'Cardinal', 'Queen' and 'Emperor' grapes were used in export chests to determine the relation of sawdust moisture content, distribution of NaHSO₃ in sawdust, distribution of dibromotetrachloroethane (DBTCE) in sawdust, and DBTCE-impregnated pads to the spread of Botrytis decay and incidence of bleaching injury of the fruit. Moisture content was directly related to decay and bleaching. Mixing of either fungistat with sawdust just prior to application to the fruit reduced overall decay and bleaching compared to top-application to the sawdust-filled chest. Vibration was not effective in distributing top-applied NaHSO₃ to the bottom of the pack, but did have some effect in distributing DBTCE. Top and bottom pads impregnated with DBTCE controlled decay to some extent in sawdust-packed grapes, but were significantly poorer than either NaHSO₃ or DBTCE powder mixed with the sawdust. DBTCE was superior to NaHSO₃ as a fungistat with respect to longevity of effectiveness and non-injury to the fruit, its pungency and lachrymatory effect made it disagreeable to handle. It was emphasized that DBTCE could not be recommended for use since the chemical has not been cleared by the Federal Food and Drug Administration for use on grapes.