Journal of Plant Disease Sciences

Rhizoctonia solani is a soil borne fungus found worldwide. It can attack roots, stem and leaves. The fungus cause significant damage of many crops. The fungus was isolated from the germinating tea seeds. After verification of Koch's postulates, the pathogenicity of the fungus was tested in seven tea seed varieties (TS 520, TS462, TS 463, TS 449, TS 464, TS 491 and TS 506). Variety (TS 520) was most susceptible and TS-449 was most resistant variety among the tested varieties. The present study deals with optimization of culture media, carbon source, nitrogen source, temperature and pH on mycelial growth and sclerotia formation. Among the several liquid and solid media tested, oat meal agar and potato dextrose broth were found most suitable for growth and sclerotia formation. Optimum pH and temperature was found to be 6.5 and 28º C respectively for growth and sclerotia formation. Mannitol supplemented media showed maximum growth among the tested carbon sources while beef extract produced maximum growth among the tested nitrogen sources.