Influence of preharvest spraying with the chemical salts on grey mold disease and keeping quality of table grapes during storage

Abstract

The efficacy of calcium chloride, calcium nitrate, potassium metabisulfate, calcium carbonate and sodium bicarbonate to protect grape bunches during harvesting was studied under storage conditions. This experiment was carried out in a private vineyard, El-Khatatba region, Alexandria desert road, Egypt during 2014 and 2015 growing seasons on Thompson seedless variety. The chemical used at 0.1 and 0.2% g /liter water. The healthy grape bunches of all treatments were harvested at proper ripeness, packed in perforated plastic bags, put inside carton boxes and stored at 0^oC under 90-95% R.H. for 36 days. Other grape bunches either treated or untreated with the salts were artificially inoculated with spore suspension of Botrytis cinerea at a concentration of 3x10⁶ spores/ml before packing and cold storage. Disease severity of grape bunches with B. cinerea was estimated after 36 days of cold storage. All treatments exhibited disease reduction under field conditions of Thompson seedless grape variety. The field applications of salts gave a significant reduction of botrytis rot during storage. In this respect, the grape rots were significantly reduced when sprayed by the salts three times.