Postharvest applicaton of fungicides, antagonists and plant products for controlling storage scab and rots of apple fruits

Abstract

Apple scab (Venturis inaequalis) is widely prevalent in all the seasons in and around Gangotri valley.Three important commercial cultivars of apple namely, 'Red Delicious', 'Royal Delicious', and 'Golden Delicious' were screened against post-harvest rot causing fungi. Fruits of the cv. Red Delicious developed more scab lesions than those of 'Red Delicious' and 'Golden Delicious'. Scab lesions gradually increased in all the fruits of Delicious cultivars stored at ambient temperature.The rate of lesion expansion was inversely related to the number of lesions on the fruit. Scabbed fruits showed pronounced shriveling as compared to healthy fruits. Other fungal pathogens associated with scab lesions were identified as Trichothecium roseum, Penicillium expansum, Glomerella cingulata, Botrytis cinerea and Monilinia spp. which were responsible for fruit decay in storage. 'Red Delicious' was highly susceptible to most of the post-harvest pathogens. Postharvest sprays of flusilazole (0.015%) bitertanol (0.075%) and carbandazim (0.05%) were effective in controlling storage scab and other rotting fungi Biocontrol agents effective against P. expansum and B. cinerea were isolated from apple leaves, and a quantitative relation between antagonists and pathogen inoculum concentration was determined. Bitertanol (0.075%) and Penconazole (0.05%) were highly effective as pre-harvest sprays for inhibiting scab lesions after 30,45 and 60 days of storage at room temperature. In protective spray programme, propineb (0.4%) was highly effective for storage rot even afer 60 days.Thiophanate methyl (0.10%) was effective against development of storage scab and fruit rot. Aonla leaf extract, garlic extract, bitertanol and carbendazim completely inhibited storage scab and fruit rot up to 60 days of post-harvest dip treatment. It could be inferred that antagonists, plant product and fungicides could make an excellent strategy for controlng postharvest losses of apple fruits and increasing shelf-life of apple.