Effect of different carbon and nitrogen sources on growth and pathogenicity of Rhizoctonia solani and Meloidygyne incognita disease complex in tomato c.v.Pusa Ruby

Abstract

Studies were made to study the effect of different carbon and nitrogen sources on the pathogenic ity of disease complex formed Rhizoctonia solani and root knot nematode Meloidogyne incognita on tomato cv Pusa Ruby. For this R. solani was cultured on different carbon and nitrogen sources. Selected carbon sources were sucrose, arabinose, glucose, fructose, rhamnose, xylose and starch. Selected nitrogen sources were KNO3, NH₄NO3,, (NH₄)₂SO_4,, Asparagine, Glycine, Lysine, Methionine and Urea. Seedlings of tomato were inoculated with R. solani and RKN separately and in combined inoculations. Plant growth, nematode multiplication and phenol contents of plants were observed for development of disease complex. Different sources show varied degrees of pathogenicity. Reduction in growth of plants was highest with fructose in case of carbon sources both in separate and combined inoculations. For nitrogen sources lysine has shown the most adverse effect on growth of plants in mono-pathogenic inoculations while urea and glycine in bi-pathogenic inoculations. Nematode multiplication was highest in glucose, glycine and KNO3 for carbon and nitrogen sources respectively. A positive correlation was observed in disease complex development and phenol concentration.