Basobi Mukherjee

Biological Control of Narrow Brown Leaf Spot and Leaf Smut Disease in Paddy Crops by Some Antagonistic Fungi

Rice is one of the most important crops worldwide. Fungal diseases in rice plants are raising concerns both in the field of research and production. Therefore, there is a definite requirement to find their control measures. In this study, an attempt was made to address the raised concerns by biologically controlling two of the least discussed diseases of the rice plants. An experiment to test potential of soil fungi as antagonists after treatment against the isolated fungal pathogens, Cercospora janseana and Entyloma oryzae was performed. In the present study, isolation of fungal plant pathogens were done from the infected plant collected from the rice field in Cauvery-Delta zone. The infected leaves were surface sterilized. Next, the efficiency of fungal isolates (ten) against Cercospora janseana and Entyloma oryzae were tested using dual culture method under in-vitro conditions. The culture filtrate test was performed to observe the maximum zone of inhibition at a particular concentration by the ten antagonistic fungi. Chemical fungicides like Carbendazim and Mancozeb were also tested using disc diffusion method. This test helped in comparison of the effects of biological control agents (antagonistic fungi) and chemical control agents (chemical fungicides). Results revealed that Trichoderma viride was found to be most effective as a biological control agent in all the tests when compared to other fungal species. All the test antagonists grew faster than the pathogens and produced inhibition zones which limited the growth of the fungal pathogens, Cercospora janseana and Entyloma oryzae. Gliocladium virens and Trichoderma harzianum also contributed in showing their antagonistic activity after Trichoderma viride. In conclusion, the three antagonistic fungi that were found to be highly efficient might be exploited commercially to biocontrol the narrow brown leaf spot and leaf smut disease. Further studies needs to be continued in this area of research.