Postharvest chlorine treatments for the control of the persimmon black spot disease caused by Alternaria alternata

Black-spot symptoms, caused by Alternaria alternata, develop in 'Triumph' p ersimmon fruit during prolonged storage at - 1 degreesC. Preharvest dip tre atment in the organic chlorine compound Troclosene sodium extended the stor age life of the fruit by delaying development of black-spot disease (BSD). Troclosene sodium was more stable and efficient for the control of A. alter nata than calcium hypochlorite. At 500 mug ml(-1) Troclosene sodium signifi cantly reduced the development of BSD in persimmon fruit sampled in 15 orch ards in different growing regions of Israel. Following commercial dipping a nd storage at - 1 degreesC, the percentage of marketable fruit after 4 mont hs of storage was 15-40% higher than in untreated fruit. Present results su ggest that the BSD can be controlled by a simple dip treatment with chlorin e disinfectant. (C) 2001 Elsevier Science B.V. All rights reserved.