ARS | Publication request: Long Term Storage of Ascosphaera aggregata and A. apis Pathogens of the Leafcutting Bee (Megachile rotundata) and the Honey Bee (Apis mellifera)

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 24, 2009
Publication Date: June 1, 2009
Citation: Jensen, A.B, R.R., Eilenberg, J. 2009. Long Term Storage of Ascosphaera aggregata and A. apis Pathogens of the Leafcutting Bee (Megachile rotundata) and the Honey Bee (Apis mellifera). Journal of Invertebrate Pathology 101:157-160.

Interpretive Summary: Chalkbrood is a disease of bees caused by the Ascosphaera fungi. Bee larvae become infected with the disease when they eat spores from these fungi. No effective way to control this disease has yet been developed, and so more scientific studies are needed to better understand the pathogen. This fungus can be difficult to work with in the laboratory, it can be difficult to grow on Petri plates, and it can be difficult to store for further studies at a later date. Different methods for the long term storage of these fungi are compared in this study. Freeze drying and cryopreservation methods (freezing at extreme temperatures) using the spores were most effective. The vegetative state of the fungus was more difficult to store long term, but cryopreservation was the most effective method. Use of long term storage methods will make it easier for scientists to compare different strains of this disease from different locations, and over different time periods.

Technical Abstract: Survival of Ascosphaera aggregata and A. apis over the course of a year were tested using different storage treatments. For spores, the methods tested were freeze drying and ultra-low temperature storage, and for hyphae, freeze drying, agar slants covered with water, and two methods of ultra-low temperature storage. Spores of A. aggregate and A. apis stored well both at -80 °C and after freeze drying. A. aggregata hyphae did not store well in any of the methods tested, while A. apis hyphae survive well using cryopreservation. Spores produced from cryopreserved A. apis hyphae were infective. Long term storage of these two important fungal bee diseases is thus possible.