Root-knot nematodes are among the most important pests that reduce tomato yield in greenhouses and fields in Iran. The scope of this research was to evaluate the antagonistic effect of Trichoderma viride and Pseudomonas fluorescens CHA0 on the reproduction and galling rate of Meloidogyne javanica in tomato roots. A pot experiment was conducted on seedlings of tomato cultivars Bony best, Falat, Mobile and Walter grown in sterilized sandy loam soil. Inocula used for artificial inoculation were 3 J2/g of soil for the nematode, 1×106 spores/ml for the fungus and 1×109 cfu/ml for the bacterium. The nematicide RUGBY® 10 G (cadusafos) was used as a reference product at 2g per each pot. Two months after inoculation, the number of knots and egg masses per root in the treatments were (with descending order): control (nematode), nematode+bacterium, nematode+fungus, nematode+fungus+bacterium and nematode+nematicide. The combination fungus+bacterium enhanced the biocontrol effect against M. javanica activity as compared to the fungus and bacterium stand-alone treatments except for the cases of the cultivars Mobile and Bonny best in which the effect was similar to the one by the fungus alone. The fungus + bacterium combined treatment was equally effective to the nematicide treatment for all cultivars. The highest and lowest rate of nematode activity was observed in Walter and Mobile cultivars, respectively.
