Bio-Control Potentials of Trichoderma spp. Against Sclerotium rolfsii the Causative of Root and Crown Rot in Tomato, Common Bean and Cabbage

In the current study, evaluation the ability of three isolates of Sclerotium rolfsii isolated from tomato, bean and cabbage to infect their host plants and two non-host plants was carried out.Tomato plants were strongly affected with the three isolates of the pathogen followed by cabbage plants, whereas common bean plants were the least in this respect.Six species of Trichoderma were examined for their bio-control potentials against S. rolfsii the causative of root rot in tomato, common bean and cabbage.In vitro antagonistic test showed that T. koningii exhibited high inhibitory effect as the percentage of inhibition value was higher in case of S. rolfsii (tomato isolate) followed by T. harzianum with S. rolfsii (bean isolate) and S. rolfsii (cabbage isolate).Under greenhouse conditions; T. koningii, T. viride and T. harzianum showed the highest antagonistic effect against the three isolates of S. rolfsii in pots experiment.Microscopic examinations showed that most of Trichoderma spp.grew over mycelia of the tested pathogen with surrounded, coiling, lysis of hyphae and collapse of mycelium.T. koningii and T. viride exhibited the best performance regarding to the defense enzyme secretion; chitinase and β-glucanase followed by T. harzianum.Also, all the tested Trichoderma spp.produced Indole acetic acid (IAA) and Gibberellic acid (GA) as a plant growth promoting substances in variable values.