Use of Rhizobacteria in the Control of Root Rot–Root Knot Disease Complex of Mungbean

Thirty-two isolates of Pseudomonas aeruginosa and a Bacillus subtilis strain were isolated from rhizosphere and rhizoplane of four wild and 15 cultivated plants. Biocontrol and growth-promoting potentials of the bacterial isolates were tested under laboratory, green- house and ®eld conditions. The bacterial isolates not only exhibited nematicidal activity by killing the second stage larvae of Meloidogyne javanica to a varying degree but also produced inhibition zones by inhibiting the radial growth of Macrophomina phaseolina, Fusarium solani and Rhizoctonia solani. Strain IE-2 and IE-6 of P. aeruginosa also lysed the fungal mycelium. P. aeru- ginosa and B. subtilis used as seed dressing or as soil drench signi®cantly suppressed root rot±root knot infection and nematode population densities under greenhouse and ®eld conditions and thereby enhanced 1plant growth and yield in mungbean.