Evaluation of the effectiveness of three fungicides against pathogens causing postharvest fruit rot of kiwifruit

Abstract

Kiwifruit is a very important crop for the Greek agricultural industry. Postharvest diseases are the cause of the most important problems of the kiwifruit. This paper considers some general aspects of the various postharvest diseases of kiwifruit in Greece. One of the main aims of this study was the investigation of the pathogens causing postharvest fruit rots in kiwifruit in Greece. The results showed that the fungus Botrytis cinerea was responsible for 100% of the postharvest fruit rots in the regions of Skydra Pella and Vrodou Katerini. This fungus was also responsible for the postharvest fruit rots at a level of 85% in the region of Chrysoupoli Kavala. The fungus Penicillium expansum was also responsible for about 12% in the region of Chrysoupoli Kavala, while the fungi Alternaria sp. and Diaporthe sp. were responsible for about 1–3% of infections. Overripe and softened kiwifruits incubated in room temperatures (about 20–23 °C) for 3 days, after 5 months cold storage, were infected with the fungus Rhizopus stolonifer. In addition, the effectiveness of the fungicides fludioxonil, fludioxonil+cyprodinil and boscalid+pyraclostrobin, applied as postharvest fruit dipping, was evaluated. None of the above fungicides has been registered for use on harvested kiwifruit in Greece although fludioxonil has been registered for postharvest applications in peach and nectarines. The results showed that all fungicides were effective against B. cinerea and P. expansum. Finally, the levels of residues of the fungicides tested in the kiwifruit were investigated about five months after their application. The results showed that only the level of residues of fludioxonil and boscalid were below of the Maximum Residue Levels (MRLs). In contrast, the residues of the cyprodinil, and pyraclostrobin were above of MRLs.