Post-harvest diseases of grapes and their control: Some aspects

Abstract

Grapes are subjected during transit and storage to the attack by many of the fungi and some bacteria. Grapes form ideal substrate for the development of storage fungi and bacteria due to high sugar content. Around 40% of losses are noticed in Telangana, Andhra Pradesh and Maharashtra, which are known to grow Grapes (Thompson Seedless, Gulabi, Bangalore Blue varieties). In our studies, it has been noticed that the grape varieties suffer heavy losses due to storage fungi represented by Aspergillus, Botrytis, Cladosporium, Fusarium, Penicillium, Mucor and Rhizopus, besides Erwinia and Xanthomonas. Because of these infections the post harvest quality of grapes is lost. It has been found that prevention methods have to be carried out to protect the post- harvest losses which include physical, chemical and biological methods. A temperature range of 36-40°C are found favorable for causing decay. Different concentrations of neem and castor leaf extracts were sprayed on the grape berries and inoculated with Aspergillus niger, Curvularia lunata, Rhizopus nigricens and observed for the growth of the fungi, after inoculation for above 5 days. Both the extracts used were found to be antifungal agents and the decay of the fruits has been reduced to a greater extent. The grape fruits were also immersed in oils of castor and neem and those were found to be effective in controlling post-harvest pathogens in our preliminary studies.