Disease management in commercial bumble bee mass rearing, using production methods, multiplex PCR detection techniques, and regulatory assessment

Recent concerns about the potential for pathogens to be transmitted from managed bumble bees and honey bees to local natural populations of bumble bees and other native pollinators have resulted in questions about the role of pathogen introductions in declines of some native Bombus species. It is in the interest of the bumble bee rearing industry, which succeeds best when managed colonies are healthy and vigorous, and the safety of the environment into which the bees are introduced, to ensure that managed bees are not foci of disease. Visual detection methods using gross pathology and light microscopy, while generally efficacious if a thorough inspection routine is followed, have the disadvantage of detecting most pathogens only after maturation to the transmissible stage. Koppert Biological Systems, the only company currently rearing bumble bees in the US, has instituted a detection method using multiplex real-time PCR to evaluate colonies for presence of three pathogens, Nosema bombi, Crithidia bombi, and Apicystis bombi, all chronic pathogens with potential to build to high prevalence in rearing facilities. Added to a rigorous inspection system, PCR methods ensure that these pathogens are detected quickly and are eliminated.