Biocontrol Potential of Fungal Antagonists from Western Himalayan Region against Sclerotial Plant Pathogens

The antagonistic potential of seventeen fungal isolates (15 Trichoderma harzianum and 2 Fusarium solani isolates), indigenous to the western Himalayan (WH) region of India, was evaluated in vitro and in glasshouse against two important stages (sclerotia and mycelium) in the infection cycle of three plant pathogens (Rhizoctonia solani, Sclerotinia sclerotiorum and Sclerotium rolfsii). The 17 isolates exhibited differential activity against different pathogens and their infectious stages (sclerotia or hyphae) with some isolates showing higher antagonistic activity against sclerotia and/or hyphae of one pathogen and poor activity against other pathogens. Out of the 17 isolates, only three isolates (S-1, S-6 and S-12) of T. harzianum, exhibited significantly higher sclerotial parasitization and hyphal inhibition activity against all the three pathogens. These isolates reduced the viability of R. solani, S. sclerotiorum and S. rolfsii sclerotia to <15, <25 and <35%, respectively, after two weeks incubation and also exhibited >46, >58 and >37% inhibition in the hyphal growth of the three pathogens, respectively. Under glasshouse conditions also the isolates exhibited significant reduction in post emergence seedling rot and white rot of garden pea as compared to control. These isolates have the potential to be exploited for management of various diseases caused by the pathogens R. solani, S. sclerotiorum and S. rolfsii, especially ia the WH region of India.