Direct effect of biocontrol agents on wilt and root-rot diseases of sesame

• Published in: Archiv für Phytopathologie und Pflanzenschutz Vol. 44; no. 5; pp. 493 - 504
• Main Authors: Elewa, I. S., Mostafa, M. H., Sahab, A. F., Ziedan, E. H.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01.03.2011; Taylor & Francis Ltd
• Subjects: B. subtilis; Bacillus subtilis; Biological control; biological control agents; Crop yield; Disease; disease incidence; disease severity; Egypt; Fungi; Fusarium oxysporum; Fusarium oxysporum f.sp. sesame; Glomus; Glomus spp; hyphae; M. phaseolina; Macrophomina phaseolina; microbial growth; Microbiology; Pathogens; Plant diseases; Rhizosphere; root rot; root systems; sclerotia; sesame; Sesamum; soil; Trichoderma viride; vascular wilt; vesicular arbuscular mycorrhizae; wilt; Egypt
• ISSN: 0323-5408; 1477-2906; 1477-2906
• DOI: 10.1080/03235400903187279

In Egypt, sesame cultivation is subject to attack by wilt and root-rot diseases caused by Fusarium oxysporum f.sp. sesami (Zap) Cast. and Macrophomina phaseolina (Maubl) Ashby causing losses in quality and quantity of sesame seed yield. Bacillus subtilis and Trichoderma viride isolates which were isolated from sesame rhizosphere were the most effective to antagonise fungal pathogens, causing high reduction of hyphal fungal growth. Trichoderma viride was found to be mycoparasitic on Fusarium oxysporum f.sp. sesami and M. phaseolina causing morphological atternation of fungal cells and sclerotial formation. In general, Bacillus subtilis, T. viride, avirulent Fusarium oxysporum isolate and Glomus spp. (Amycorrhizae) significantly reduced wilt and root-rot incidence of sesame plants at artificially infested potted soil by each one or two pathogens. Data obtained indicate that Glomus spp significantly reduced wilt and disease severity development on sesame plants followed by T. viride. Meanwhile, avirulent Fusarium oxysporum isolate followed by Glomus spp. were effective against root-rot disease incidence caused by M. phaseolina. Glomus spp. followed by B. subtilis significantly reduced wilt and root-rot disease of sesame plants. All biotic agents significantly reduced F. oxysporum f.sp. sesami and M. phaseolina counts in sesame rhizosphere at the lowest level. Glomus spp. and the avirulent isolate of F. oxysporum eliminated M. phaseolina in sesame rhizosphere. Meanwhile T. viride was the best agent at reducing F. oxysporum at a lower level than other treatments. Application of VA mycorrhizae (Glomus spp.) in fields naturally infested by pathogens significantly reduced wilt and root-rot incidence and it significantly colonised sesame root systems and rhizospheres compared to untreated sesame transplantings.