MICROBIOLOGICAL STUDIES ON CHALK-BROOD DISEASE IN HONEYBEE COLONIES IN EGYPT | ||||
| Journal of Plant Protection and Pathology | ||||
| Article 3, Volume 30, Issue 11, November 2005, Page 7089-7102 PDF (4.46 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jppp.2005.239267 | ||||
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| Authors | ||||
| Olfat S. Barakat1; M. A. Abd-Alfattah2; M. A. Ali1; Gelan M. Ibrahlm3 | ||||
| 1Agricultural Microbiology Dept., Fac. of Agrlc., Cairo Univ., Giza. | ||||
| 2Department of Economic Entomology, Fac. of Agric., Cairo Univ., Giza. | ||||
| 3Bee Division, Plant Protection Institute, ARC, Giza. | ||||
| Abstract | ||||
| Chalk-brood disease in honeybee larvae, caused by the heterothallic fungus Ascosphaera ap < /em>is, was recently diagnosed in Egypt in 1995 and is regarded lately as a threat to the Egyptian honeybee keeping. Effective control of such disease is currently unavailable all over the world, and the most common practice is to re-queen from different genetic stocks. This work was undertaken to study some morphological, cultural and physiological characteristics of Ascosphaera ap < /em>is isolated from honeybee colonies in Egypt. Microorganisms associated with chalk-brood mummified honeybee larvae were also examined using different culture media. The results showed that A. apis was the most prevalent fungus in chalk-brood mummified larvae, representing 33.3% of the isolated microorganisms from all the examined media followed by Aspergillus. fumigatus (27.4%) and Aspergillus flavus (14.1%). Bacteria and yeasts represented 12.6 and 10.6% of the total number of microorganisms isolated from mummified larvae, respectively. Potato Dextrose yeast Agar was the most proper medium for isolation, cultivation and characterization of this fungus followed by malt Agar and Saboruad's Agar. The antifungal activities of essential oils from sweet marjoram (Majorana hortensis), basil (Osinum basilicum), peppermint (Mentha peprita) and spearmint (Mentha viridis) against A. apis were examined, both in vitro and in vivo. Marjoram and peppermint oils were the most effective against growth in vitro of the fungus. Feeding honeybees with sugar syrup containing 0.5 or 1 % of marjoram oil resulted in reductions in the percentages of chalk-brood mummies comparable to those obtained with application of 40% formic acid solution. Screening of some microorganisms for antibiosis towards A. ap < /em>is showed that Bacillus spp < /em>. (CHBr), isolated from mummified honeybee larvae, was the most potent antagonistic candidate compared to the other examined microorganisms. Preliminary investigation of in vivo antagonistic capabilities of this bacterium suggested a possible integration of such bioagent along with sweet mariorarn essential oil into a management strategy for chalk-brood biological control. | ||||
| Keywords | ||||
| Ascosphera apis; antifungal activities; essential oils; Bacillus antibiosis | ||||
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