Effects of cell suspension and cell·free culture filtrate of Pseudomonas aeruginosa in the control of root rot-root kont disease complex of tomato (Lycopersicon esculentum Mill.)

Abstract

The plant growth-promoting rhizobacterium <i>Pseudomonas aeruginosa</i> strain IE-6 was tested for antagonistic activity towards <i>Meloidogyne javanica</i>, the root-knot nematode and soilbome root-infecting fungi viz., <i>Macrophomina phaseolina</i>, <i>Fusarium solani</i> and <i>Rhizoctonia solani</i> under laboratory and greenhouse conditions. Cell-free culture filtrate of the bacterium caused significant reduction in egg hatching of <i>M.javanica</i> and inhibited radial growth of fungi <i>in vitro</i>. Cell-free culture filtrate also caused lyses in mycelium of <i>F.solani</i>. Under greenhouse conditions, soil drenches with the aqueous cell suspension or cell-free culture resulted in a considerable reduction in nematode population densities in soil and subsequent root-knot development due to <i>M.javanica</i>. In addition to nematode control, rhizobacterium application also inhibited root-infection caused by soilborne root~infecting fungi with significant enhancement of growth of tomato seedlings.