Rinku Bhaskar, Ramesh Singh, Prashant Mishra, Gopal Singh, Hem Singh and Manoj Kumar Singh
Abstract
Early blight of potato caused by Alternaria solani is one of the most destructive foliar diseases affecting potato production worldwide. The present investigation was undertaken to assess the disease incidence, isolate and characterize the pathogen, and evaluate the efficacy of fungicides and bioagents against A. solani under in vitro conditions. A comprehensive roving survey conducted during the rabi seasons of 2024 25 and 2025-26 in different blocks of Meerut district revealed widespread occurrence of early blight with disease incidence ranging from 4.10-20.72 and 5.35-18.68 per cent, respectively. Maximum disease incidence was recorded in Daurala block during both the years, whereas Hastinapur exhibited the lowest incidence. The pathogen was isolated from infected potato leaves and identified based on cultural and morphological characteristics, including dark brown to black colonies with concentric zonation and multicellular beaked conidia typical of A. solani. In vitro evaluation of fungicides by the poisoned food technique revealed that propiconazole 25% EC was the most effective fungicide, recording maximum inhibition of mycelial growth (91.12%) at 12 days after inoculation (DAI), followed by difenoconazole 25% EC (87.04%) and hexaconazole 5% EC (84.97%). Among the bioagents tested under dual culture conditions, Trichoderma viride isolate TS006 proved most effective with 70.57 per cent inhibition of mycelial growth at 12 DAI, followed by Bacillus subtilis isolate B005 (61.64%). The present findings indicate that triazole fungicides and T. viride possess significant potential for effective management of potato early blight and may be integrated into sustainable disease management strategies.