Satish KumarDhawan, Aman2017-03-272017-03-272016http://krishikosh.egranth.ac.in/handle/1/5810006098Clusterbean [Cyamopsis tetragonoloba (L.) Taub.] is an important industrial crop of India. Among the various diseases, dry root rot disease causes heavy losses every year. The dry root rot fungus R. bataticola was isolated from root rot infected clusterbean plant and the pathogenicity of the fungus was established by satisfying the Koch's postulates. Different inoculum levels of homogenized mycelial and mycelium embedded sclerotia on pre and post-emergence plant mortality of clusterbean cv. HG-365 revealed that plant mortality was directly proportional to the inoculum levels. Mycelium embedded sclerotial culture of R. bataticola was comparatively less virulent at all the inoculum levels as compared to their same level of mycelium culture. Cowpea was recorded as most favoured host for maximum pycnidia production (29.7/cm2 surface area) as compared to clusterbean (27.7/cm2 surface area). No pycnidia were noticed on cotton, okra, mung bean and urd bean plant parts. Stem of cowpea and clusterbean appeared as good substrate for pycnidia production followed by leaves. Root parts did not support the production of pycnidia on any of the tested crops. Pycnidiospores were able to produce disease symptoms on germinated seedlings of cotton, cowpea, clusterbean, okra, mung bean and urd bean. Out of sixteen clusterbean genotypes screened under screenhouse conditions in artificial inoculated disease stress conditions, none of the genotype was found resistant to R. bataticola, however, only two genotypes viz. HG-100 and HG-75 were categorized as moderately resistant with a total plant mortality of 16.7 per cent and 20.0 per cent, respectively. A minimum disease incidence of 33.3 and 39.9 per cent was recorded when the seeds were coated with bavistin followed by captan+hexaconazole. A minimum disease incidence of 36.9 and 39.9 per cent was recorded when the soils were incorporated with mustard cake followed by cotton cake. The disease control was directly proportional to the dose of VAM. A maximum of 40 per cent disease control was recorded when the soils were incorporated with 600 sporocarps/kg soil followed by 25 per cent when soils were incorporated with 500 sporocarps/kg soil. The disease control was improved by increase in the dose of soil application of T. viride. A maximum of 34.8 per cent plant disease control was recorded when the soils were incorporated with T. viride at the rate of 10g/kg soil. Seeds treated with bavistin and sown in T. viride and mustard cake incorporated soil gave a maximum of disease control of 74.8 per cent in clusterbean cv. HG-365 as compared to control whereas, seeds treated with bavistin and sown in T. viride and mustard cake incorporated soil gave a maximum of disease control of 80.8 per cent in clusterbean cv. HG 2-20 as compared to control.enThesis