Prevalence, incidence and management of fruit rot of pears incited by Acremonium kiliense

In Kullu valley, an outbreak of immature fruit rotting of pears was observed during 2013 in 5 orchards at Darka and Katrain locations. the disease was continuously monitored for its time of appearance and prevalence by conducting periodical surveys during the past four years (2014–2017) in 39 orchards at 13 locations which revealed the prevalence of the disease ranging between 1.3 to 70.2% with an overall mean incidence 30.04%. the disease mainly appeared in the month of July and the orchards located in Fojal valley (5000–6000’) were found severely affected with mean incidence 39.47% followed by orchards situated in Lag valley (4000–5000’) with mean incidence 36.7% where the infected fruits were seen having water soaked lesions turning brown to dark brown anywhere on the fruit but mostly from calyx end. Initially the affected fruits were firm but later turned soft having watery discolouration of interior tissues with browning. Later, such fruits were found covered with white arachnoid mycelial growth turning grey causing large scale dropping of the fruits. the pathogen associated with the disease was identified as Acremonium kiliense and its pathogenicity established. the disease appeared maximum during second week of July 2015 when a temperature ranged from 21.8 to 24.8⁰c and rh 71.3–82.4% coupled with high rainfall conditions. A high disease incidence was observed during July in 2015 and 2017 due to occurrence of high rainfall 235.4 and 225.3mm in June and July, respectively. The disease was observed on Bartlett and Red Bartlett cultivars only where as baggugosha and Kashmir pears were free of this disease. apple fruits were also found infected in the orchards where mixed cultivation of pears and apple was practiced. cross inoculation studies carried on apple fruits also showed its susceptibility to this pathogen. twelve non systemic and systemic fungicides were evaluated in vitro against the pathogen to find out effective ones. Mancozeb (0.3%), combi-product of carbendazim and mancozeb (0.25%) and Ziram-80 (0.3%) were found potent growth inhibitors. these fungicides in a sequence of mancozeb (0.3%) - carbendazim + mancozeb (0.25%) - Ziram-80 (0.3%) were further evaluated under field conditions in three different time schedules of spray in hot spot area in Fojal valley for two consecutive years. Though, all time schedule sprays provided significant control of the disease but, schedule II (1^st spray during 2^nd week of June, 2^nd spray in 4^th week of June and 3^rd spray in 2^nd week of July) provided maximum disease control to the extent of 94.17%.