BIOLOGICAL CONTROL OF COLLAR ROT (PHYTOPHTHORA CACTORUM) OF APPLE
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Date
2023-11-28
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UHF,NAUNI
Abstract
The present investigation titled, “Biological Control of Collar Rot (Phytophthora cactorum) of Apple" was carried out at laboratory and experimental farm of Department of Plant Pathology, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP)-173 230 during 2022-2023. Surveys were conducted to record the incidence of collar rot of apple in different apple growing locations of Mandi, Kullu and Shimla districts of Himachal Pradesh. Among the different blocks surveyed, the collar rot disease was more prevalent in Rohanda block of Mandi district with mean disease incidence of 34.5 per cent. Different antagonists were tested for their efficacy against the test fungus under in vitro conditions by two different methods viz., Dual culture and Volatile compound evaluation. In dual culture method, maximum inhibition of pathogen radial growth was observed in Bacillus cereus (65.56%), Bacillus cereus strain SG1 (64.07%), Exiguobacterium aurantiacum (63.33%) and Trichoderma virens (62.59%) and minimum inhibition of pathogen radial growth in Trichoderma sp. (51.48%) and Pasteurella dagmatis (48.89%). In volatile compound evaluation method, maximum inhibition of pathogen radial growth was observed in Exiguobacterium aurantiacum (65.56%), Bacillus cereus (64.44%), Staphylococcus xylosus (64.43%) and Trichoderma virens (39.26%). Bacterial antagonist Pasteurella dagmatis, Ochrobactrum intermedium and Trichoderma sp. were least effective with radial growth inhibition of 0.00, 0.00 and 15.56 percent, respectively. Among seven most effective antagonists evaluated for their efficacy against collar rot of apple under pot conditions, maximum disease control was observed in Bacillus cereus, Exiguobacterium aquaticum and Trichoderma virens which provided 84.21, 78.94 and 76.32 percent disease control and minimum disease control was reported in Alcaligenes faecalis (44.74%). Thus, the exploitation of these antagonists as soil application can provide a more efficient and eco-friendly management of collar rot of apple caused by Phytophthora cactorum.