Response of French Bean (Phaseolus vulgaris L.) to Disease Complexes Involving Meloidogyne incognita and Rhizoctonia solani

The interactions involving root-knot nematode, Meloidogyne incognita and root-rot fungus, Rhizoctonia solani on potted bean plants (Phaseolus vulgaris L.) were investigated with artificial inoculations. The study revealed that there was a significant reduction in shoot and root lengths, their fresh weights and number of pods in the plants receiving the inoculum of the fungus and nematode simultaneously. The fungus alone caused comparatively less effect than the nematode. Similar progressive decrease in chlorophyll and carotenoid content was also observed in concomitant inoculations. The root-knot index was highest where nematodes were inoculated singly and was a significantly reduced in presence of fungus. Conversely, the simultaneous inoculation of both the pathogens gave maximum root-rot index.