U. GuptaMd. Reyaz Ahmad2024-06-222024-06-221995https://krishikosh.egranth.ac.in/handle/1/5810210757Ragi blast, etiologically associated with the fungal pathogen, (Pyricularia grisea (Cke) Sacc.) is the most rigorous allment in Chotanagpur plateau region of Bihar. In view of its increasing importance, studies this very on epidemiology and management were carried out. disease emphasizing The morphological characters of P. grisea were studied both from nature as well as culture and has been described in detail. The congenial temperature (28 C) was found to be the best for growth and sporulation of P. grisea and grew best on Host leaf extract agar and Richards' solution at pH 7.0 but sporulation was found to be the best on Oat meal agar and Glucose-Peptone medium. Glucose and Peptone were found to be the best sources of carbon and nitrogen whereas any fluctuation in the C/N ratio other than 1:1 caused reduction in growth and sporulation. Conidia germinated well at 28 C and between pH 5 to 7. Maximum perpetuation period of the pathogen was recorded to be four months in Infested fingers at 2.5 cm soil depth. And, it was observed to perennate on a number of weed hosts growing in and around ragi field. Of these wild Eleusine and wild Panicum were found to be the most important collateral hosts. The most susceptible age of the ragi plants against P. grisea was found to be 60 days with respect to disease development.EnglishThesis