| Abstract | Fusarium solani is one of the most common pathogens, causing damping-off disease of faba bean (Vicia fabe L.) in Egypt. All the obtained isolates were able to attack faba bean plants (cv. Sakha1) causing damping-off disease. Isolate 2 (identified as F.solani) was the most virulent ones in the pathogenicity test. The antagonistic effect of three Trichoderma species, i.e. T.harzianum, T.hamatum, and T.virens was tested against F.solani in vitro and in greenhouse experiments. In vitro, all Trichoderma spp., significantly reduced the mycelial growth of F. solani and showed a mycoparasitic activity against the pathogenic fungus. In greenhouse experiments, the combined effect of Trichoderma spp. (as seed or soil treatments) and Rhizobium leguminosarum bv.viceae significantly reduced the pre-and post-emergence damping-off disease incidence under artificial infection with F. solani. The best protection to damping- off disease was obtained by T.virens (as soil treatment), followed by T.harzianum and T.hamatum, respectively. The treatments gave the highest values of plant survival (%) and improved the growth parameters, symbiotic N2 fixing and yield components, compared with infested control. The effects were similar in more cases to those of the fungicide Rizolex-T50%, which reduced the damping-off disease incidence but adversely affected Rhizobium sp. and the symbiotic N2 fixing parameters. Sensitivity test of the Rhizobium and Trichoderma strains with some chemical pesticides (Rhizolex-T50, ground-up, malathion and Rugby) was applied. All tested fungicides showed toxic effects to Rhizobium and Trichoderma strains, even at low concentrations. The fungicide Rizolex-T50% was the most effective one even at the one forth recommended dose |