Characterization of the Causative Agent of Chalkobroood Disease of Honeybee Brood (Apls Melliferal.) in Ethiopia

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Addis Ababa University


Chalkbrood disease is an invasive mycosis of honeybee larvae (Apis mellifera L) caused by Ascosphaera apis (Maassen ex Claussen) Spiltoir and Olive (1955). The causative agent of this disease occurs in most bee keeping countries of the world. This study aims to characterize the causative agent of the disease and compares it with reference strain (MUCL 34668). The mummies were surface disinfected and inoculated onto Sabouards Dextrose Agar for macroscopic and microscopic identification. The local isolates were also compared with the reference strain, assayed for proteolytic ability, toxicity, and virulence on honeybee larvae in the laboratory and in the hive. Microbiological analysis of 45 samples of dead honeybee larvae collected from the regions during 2004-2006 yielded 28 positive cases for chalkbrood disease incidence (62.22%). Spore cyst, spore ball, and ascospores length to width ratios measured with phase contrast inverted computer fitted microscope were 66.15 –97.66 m, 11.00 –19.27 m and 2.00-2.95 m, respectively. The measurements obtained and examination results enabled us to confirm that the local isolates belongs to the genus Ascosphaera and to the species Ascosphaera apis. Key words: Chalkbrood disease, Ascosphaera apis, spore cyst, spore ball, Ascospores, Apis mellifera.



Chalk Brood Disease, Ascosphaera Apis, Spore Cyst, Spore Ball, Ascospores, Apis mellifera