Incidence and etiology of mouldy core and core rot of apple in Shimla district, Himachal Pradesh

The investigations on the incidence and etiology of mouldy core and core rot of apple causing pre-harvest fruit drop in major apple growing belts in Shimla district of Himachal Pradesh were conducted during 2009 cropping season. Highest incidence (17.7%) of mouldy core and core rot of apple in dropped as well as intact fruits was found in the Kotkhai region of the Shimla district followed by Rohroo (16.6%) and Thanedhar (15.5%) while least was observed in Jubbal area. The percentage incidence of mouldy core and core rot of apple was more in the dropped (30.1 and 17.1%) fruits as compared to the intact ones (12.4 and 5.1%). Alternaria alternata was the predominant fungal pathogen isolated from the infected fruits. In a few cases Trichothecium roseum was observed as a secondary pathogen causing dry rot symptoms. Artificial inoculation of the mature fruits through calyx tube showed 100 per cent rotting after 25 days of inoculation.