EFFECTS OF CERTAIN ANTAGONISTIC FUNGI AND RHIZOBACTERIA ON WILT DISEASE COMPLEX OF TOMATO CAUSED BY MELOIDOGYNE INCOGNITA AND FUSARIUM OXYSPORUM F. SP. LYCOPERSICI

Abstract

An investigation was carried out to examine the effect of soil application of Paecilomyces lilacinus, Gliocladium virens, Pseudomonas fluorescens PRS-9, Bacillus polymyxa and pesticides (aldicarb + thiram) against a disease complex caused by Meloidogyne incognita and Fusarium oxysporum f. sp. lycopersici on growth and yield of tomato in field plots. The nematode and fungus, acting alone caused characteristic root galling and shoot wilting, respectively and significantly reduced plant growth and yield. In concomitant inoculation, severity of fusarial wilt was significantly increased and plant growth and yield reductions were also considerably greater compared to the sum of individual effects of the pathogens. On such plants, pathogenesis and reproduction of the nematode was, however, suppressed. Application of P. lilacinus and G. virens significantly enhanced the plant growth and yield of nematode and fungus inoculated plants, respectively. Greatest enhancement of plant growth and yield of nematode-fungus infected plants occurred with P. fluorescens, followed by the pesticides and G. virens or P. lilacinus. Hatching of larvae, gall formation, egg mass production, fecundity and soil population of M. incognita and wilting index and rhizospheric population of F. oxysporum f. sp. lycopersici were decreased due to application of the control agents except B. polymyxa, which caused increase in the dry matter production and yield of uninfected tomato plants and soil population and fecundity of the nematode and rhizosphere population of the fungus.