Abstract
Several laboratory techniques for detecting significant bacteria of diseased honey bees (Apis mellifera L.) were compared. Bacillus larvae, Bacillus alvei and Bacillus laterosporus spores were easily differentiated in larval cadavers by their surface configuration as seen by scanning electron microscopy. Melissococcus pluton and Achromobacter eurydice vegetative cells were also distinguishable. Using this method, confirmation of B. larvae, the causative agent of American foulbrood, could be achieved In less than 48 h. The Incubation-heating procedure In nutrient broth or the incorporation of nalidixic acid In culture media were also satisfactory for the isolation of B. larvae from samples with mixed bacterial spore populations.