Two Pathogenic Fungi Isolated From Chalkbrood Samples and Honey Bee Viruses They Carried

Area of Science:

• Mycology
• Virology
• Apiculture
• Insect Pathology

Background:

• Ascosphaera apis and Aspergillus species are primary honey bee pathogens.
• The pathogenesis of chalkbrood and stonebrood diseases is not fully understood.
• The role of co-infecting agents in honey bee fungal diseases requires further investigation.

Purpose of the Study:

• To investigate the role of Aspergillus tubingensis in honey bee chalkbrood.
• To identify other pathogens, particularly viruses, associated with A. apis and A. tubingensis.
• To elucidate the transmission mechanisms of identified honey bee viruses within fungal hosts.

Main Methods:

• Isolation and identification of Aspergillus tubingensis from chalkbrood bee samples.
• Pathogenicity tests using single and combined fungal inoculations.
• Detection and quantification of honey bee viruses (ABPV, CBPV) in fungal cultures using molecular methods.
• Analysis of viral transmission via fungal spores and hyphal anastomosis.

Main Results:

• Aspergillus tubingensis was isolated from chalkbrood samples for the first time.
• A. tubingensis promoted A. apis spore accumulation and contributed to chalkbrood/stonebrood symptoms.
• Acute bee paralysis virus (ABPV) and chronic bee paralysis virus (CBPV) were detected and replicated within A. apis and A. tubingensis.
• CBPV demonstrated vertical transmission through spores and horizontal transmission via hyphal anastomosis.

Conclusions:

• Honey bee chalkbrood involves complex interactions between multiple fungal pathogens and viruses.
• The presence and interaction of A. tubingensis and honey bee viruses (ABPV, CBPV) influence disease dynamics.
• Fungal-viral interactions, including novel transmission routes, are critical factors in honey bee disease outbreaks and warrant further study.