The effects of salicylic acid (SA), Trichoderma viride and Pseudomonas fluorescens CHA0 were studied on the root-knot nematode Meloidogyne incognita race 2 in resistant and susceptible tomato cultivars (Gina VF, Falat CH, Falat 111, Karoon) during 2012-2013. Four-leaf tomato seedlings were used, grown in pots containing 1000 g of sterilized soil; each seedling receiving 20 ml of T. viride suspension containing 1×106 spores, 30 ml of P. fluorescens CHA0 with 109 cfu/ml, 5mM of salicylic acid and 2000 second stage nematode juveniles. Parameters relevant to nematode population and plant growth were evaluated. The biocontrol agents and salicylic acid were effective in nematode control in combined and single treatments. High reductions in root galling and egg mass indices were observed with combination of SA and biocontrol agents. The greatest increase in plant growth was obtained when cv. Falat CH was treated with SA followed by P. fluorescens CHA0 and T. viride. The highest number of galls was recorded in cv. Karoon, followed by cvs. Falat 111, Gina VF and Falat CH. Pseudomonas fluorescens CHA0 provoked the highest increase in fresh and dry root weight, fresh and dry shoot weight and plant length in all free nematode treatments. The results indicated that chemical inducer (salicylic acid), in combination with biocontrol agents (T. viride and P. fluorescens CHA0), stimulated and eventually increased plant growth.
