Synergistic Effect of Meloidogyne incognita and Rhizoctonia bataticola Causing Root Rot Diseases of Cotton

Abstract

Root rot disease complex attributed to Meloidogyne incognita and Rhizoctonia bataticola is a serious threat to cotton in areas having warm climate. In this study, the impact of M. incognita and R. bataticola interaction was assessed at different levels of resistance and susceptibility in cotton. M. incognita and R. bataticola were inoculated on various cotton varieties, alone and in combination. Variety CRS-134 showed high resistant against R. bataticola after individual inoculation with 1.7 disease severity ratings (5-10% infection) whereas varieties FH-4243, MNH-554 and FH-183 were moderately resistant with 2.2, 2.1 and 2.4 disease severity ratings, respectively. Inoculation of M. incognita and R. bataticola in combination significantly enhanced the root rot severity in cotton. Results showed that in the presence of both M. incognita and R. bataticola, the disease severity increased to 6.2 in CRS-134, 4.9 in FH-4243, 5.9 in MNH-554 and 3.6 in FH-183. Hence, the synergistic effect of M. incognita and R. bataticola has drastic impact on cotton and could be minimized using resistant varieties.