Comparative Study on the Activity of Trichoderma asperellum and T. Album and Their Role in Controlling Faba Bean Root Rot and Wilt Diseases

Trichoderma spp are the most important soil fungi in Egypt. This study was initiated to evaluate Trichoderma asperellum and T. album used to produce Bio-Nagi and Bio-Zeid biocide products, respectively. The mycelial growth of Trichoderma isolates was tested in response to temperature effect. The most growth of T. asperellum was obtained at 25-30°C, while incubation at 35°C showed slow growth rate to fill up 9 cm Petri plate at 15days. No mycelial growth was observed after incubation at 4, 37 and 40°C for 5, 10 and 15 days, respectively. Meanwhile, when these Trichoderma plates were re-incubated in the optimum temperature at 25°C they showed fast growth rate in those exposed previously to 4 and 37°C to fill up the plates completely within 3 days, but for those exposed previously to 40°C, no growth was noticed. In vitro, the two Trichoderma isolates inhibited the mycelial growth of Fusarium oxysporum and Rhizoctonia solani. The highest growth reduction values (66.7 and 58.4%) and (54.2 and 53%), against R. solani and F. oxysporum were obtained with Bio-Nagi and Bio-Zeid, respectively. Also, Trichoderma isolates produced volatile compounds having significant effect in reducing the mycelial growth of the two pathogenic fungi. Four carriers’ formulae (Imported and local soybean flours, Sawdust and Yeast extract) were separately mixed up, leach with the two isolates of Bio-Nagi and Bio-Zeid and were evaluated in vitro and in vivo. The most effective for preservation temperature of the two biocides in each formula, was calculated when stored at 4oC than at room temperature, which recorded the highest viability and spore germination, then decreased gradually by increasing storage period from 3 to 12 months. All tested Trichoderma carrier formulations added to soil infested with pathogen significantly decreased wilt and damping off diseases and increased plant survival of faba bean, in greenhouse compared with infected control. The two Bio-Nagi and Bio-Zeid biocide formulae were antagonistic against the two pathogenic fungi and recorded the highest efficacy in reducing wilt and damping-off caused by F. oxysporum and R. solani. Application of Bio-Nagi + Imported soybean flour was the most effective formulation, gave the highest reduction in the percentage of wilt and damping off followed by Bio-Nagi+ Local soyben flour and Bio-Zeid+ Imported soybean flour against the two pathogens.