Chalkbrood is a fungal disease of honey bee brood caused by Ascosphaera apis. This disease is now found
throughout the world, and there are indications that chalkbrood incidence may be on the rise. In this
review we consolidate both historic knowledge and recent scientific findings. We document the worldwide
spread of the fungus, which is aided by increased global travel and the migratory nature of many
beekeeping operations. We discuss the current taxonomic classification in light of the recent complete
reworking of fungal systematics brought on by application of molecular methods. In addition, we discuss
epidemiology and pathogenesis of the disease, as well as pathogen biology, morphology and reproduction.
New attempts at disease control methods and management tactics are reviewed. We report on
research tools developed for identification and monitoring, and also include recent findings on genomic
and molecular studies not covered by previous reviews, including sequencing of the A. apis genome and
identification of the mating type locus.
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