Browsing by Author "Dagnew, Wubet"

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    Incidence and Phenotypic Characteristics of Coffee Berry Pathogen (Colletotrichum Kahawae) from Sidama and Gedeo Zones and its Control Using Trichoderma Isolates.
    (Addis Ababa University, 2018-05-04) Dagnew, Wubet; Alemu, Tesfaye (PhD)
    The experiment was done to assess incidence, severity and variations in Colletotrichum kahawae isolates. Assessment was conducted in Aleta Wendo, Yirgacheffe, Shebedino, Wenago and Dale of Gedeo and Sidama Zones of Southern Region by examining and recording of the incidence and severity of CBD. The survey revealed that CBD was prevalent in all the surveyed districts. The overall mean incidence and severity at district level were 47.9 and 29.0%, respectively in 2015 cropping season and 40.0 and 25.6%, respectively in 2016 cropping season. Seven representatives of Colletotrichum kahawae isolates were isolated from Southern region of Ethiopia and were studied based on their cultural and morphological characters. Isolates were grouped into 4 based on their colony color manifestation on PDA and MEA. The cultures exhibited light gray, gray, dark gray and dark olive green mycelia forms. Mean radial colony growth rate of Colletotrichum kahawae isolates were 4.8, 5.1, 5.0 and 4.4mm/24hr on PDA, MEA, fruit and leaf extracts, respectively. Conidia width and length ranged as 3.5 – 6.7 µ m and 14.0 – 17.8 µ m, respectively. High variation was observed among Colletotrichum kahawae isolates in their sporulation capacity, and varied between 4.83 x 105 and 2.14 x106conidia/ml. An in vitro evaluation of dual culture technique and detached berry test exhibited that the mycelial growth of the pathogenic fungus is suppressed by Trichoderma isolates. Two isolates of Trichoderma showed overgrowth on Colletotrichum kahawae isolates with average inhibition of 74.54 % and 75.75 % by AUTI and AUT2 isolates, respectively; and there was no disease symptom appearance when Colletotrichum kahawae isolates were with Trichoderma isolates inoculated on detached green berries.