Most beekeepers will be familiar with the fungal disease chalkbrood, which is generally considered to be only of minor importance, but it remains a mysterious disease, and in some areas can be devastating. In a new paper published in the Journal of Apicultural Research, Dafu Chen and colleagues from the Fujian Agriculture and Forestry University, China have examined chalkbrood in the eastern hive bee Apis cerana, and compared it with that found in the western honey bee Apis mellifera.
Ascosphaera apis, the causative organism of chalkbrood has been found in Apis mellifera, Apis cerana, Xylocopa californica arizonensis larvae as well as adult bumble bees. Here, the fungal pathogen of Apis cerana cerana drone mummies was isolated and identified using morphological and molecular methods. Morphological observation indicated that the sizes of the fruiting bodies, spore balls and ascospores of the fungus isolated from A. c. cerana drone mummies were similar to those of A. apis. Phylogenetic analysis suggested that the fungus is identical to A. apis. Furthermore, the results of a cross infection assay demonstrated that the isolated fungus is capable of infecting eastern and western honey bee larvae and results in chalkbrood disease. These results confirmed that the isolated fungal pathogen is A. apis. This is the first documentation of morphological and molecular identification of A. apis in A. c. cerana. The autgors conclude that their results not only provide novel insight to better understand the pathology of A. apis, but also lay a solid foundation for further investigations of host responses and pathogen-host interactions during chalkbrood of eastern honey bee larvae.
The paper: “Morphological and molecular identification of chalkbrood disease pathogen Ascosphaera apis in Apis cerana cerana” can be found here:
The COLOSS BEEBOOK chapter which covers chalkbrood, “Standard methods for fungal brood disease research” can be found here (Free to view):
You can buy the hard copy of the COLOSS BEEBOOK Volume II “Standard methods for Apis mellifera pest and pathogen research” which contains the chapter on fungi can be purchased from the IBRA Bookshop for £60 + postage:
And finally, here is a thoughtful piece from Bee World by the late Prof. Len Heath, one of the foremost authorities on chalkbrood disease. The article: “Endemic or epidemic? Sense & nonsense in bee hygiene” can be found here: https://www.tandfonline.com/…/10.1080/0005772X.1993.11099148
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