Effect of Some Physical Factors, Fungicides on Growth of Rhizoctonia solani Kuhn and Fungicidal Seed Treatment on Groundnut Seed Germination

Among the tested solid media, Czapek's agar was the best in supporting mycelial growth of Rhizoctonia solani Kuhn while groundnut kernel extract broth was the most supportive among the tested liquid media. Growth of R. solani was the best at 30°C, 80 per cent relative humidity and 6.5 pH. Among the tested fungicides, carbendazim and thiram completely inhibited the mycelial growth of R. solani at all concentrations while chlorothalonil seemed least inhibitory to the fungus: Thiophanate methyl provided the highest seed germination among the tested fungicides at 50 ppm and it was at par with the best carbendazim at all other concentrations. Seed treatment with thiophanate methyl provided the best seedling length among the tested fungicides at 500 and 1000 ppm while carbendazim was the best at lower fungicidal concentrations.