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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/3303

Title: Characterization of antagonistic Trichoderma
Authors: Yonas, Urbanos
Advisors: Tesfaye Alemu(Dr.)
Keywords: Biological Control agents
Cofffee wilt disease
Fusarium xylarioides
Trichoderma isolates
Copyright: Dec-2010
Date Added: 5-Jul-2012
Publisher: Addis Ababa University
Abstract: In vitro antagonistic activity of Trichoderma isolates against coffee wilt disease (CWD), Fusarium xylarioides (Gibberella xylarioides) was studied. Out of 32 soil samples and 7 coffee tree parts collected from 6 different coffee growing woredas of Jimma Zone, 7 potential/effective Trichoderma isolates were isolated and characterized out of 74 fungal cultures. Trichoderma isolates were characterized based on spore morphology and vegetative growth characterizations on different growth media, temperature and pH ranges. The most suitable and maximum growth of Trichoderma isolates was obsereved at pH 4.5 and 5.5 in all of the isolates. In vitro evaluation of dual culture test was done for each of the seven Trichoderma isolates against F. xylarioides. It was observed that all of the seven Trichoderma isolates have shown 63.33 to 70.95 percent of mycelial growth inhibition of F. xylarioides after 6 days of incubation at 250C on potato dextrose agar medium. Trichoderma isolate AUT4 was the most effective biocontrol agent which exhibited the maximum inhibition of 70.95%. Whereas, the least percent of mycelial growth inhibition 63.33% was obtained by Trichoderma isolate AUT3. In addition to the above, the seven isolates of Trichoderma were then tested for their production of volatile antifungal compounds against F. xylarioides. They produced volatile compounds which inhibited the mycelial gorwth of the test pathogen from 66 to 80.60%. Trichoderma isolate AUT1 produced the most effective volatile compounds which inhibited growth by 80.60%. Therefore, the application of in vitro evaluations of seven Trichoderma isolates has proved to be highly potential/effective in the control of coffee wilt diseases (Fusarium xylarioides).
Description: A Thesis submitted to the School of Graduate Studies of Addis Ababa University in partial fulfillment of the requirements of the Degree of Master of Science in Applied Microbiology
URI: http://hdl.handle.net/123456789/3303
Appears in:Thesis - Biology

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