The use of hen egg white lysozyme to control chalkbrood disease in honey bee colonies

Chalkbrood, caused by Ascosphaera apis (Maassen ex Claussen) Spiltoir and Olive (1955), is a cosmopolitan fungal disease of honey bee larvae (Apis mellifera L.) for which there is no registered chemotherapeutic control. Previously, it was determined that lysozyme-HCl, a broad spectrum antimicrobial extracted from hen egg albumen, was effective at controlling chalkbrood in vitro. A field trial was conducted in which 40 artificially-infected package colonies were inoculated with pollen containing homogenized black and white chalkbrood mummies and administered three treatments of 600, 3000, or 6000 mg lysozyme-HCl in 50% (w/v) sucrose syrup. Colonies were evaluated for disease severity, brood and adult bee populations and honey production over spring and summer months. Lysozyme-HCl was not found to affect adult bee survival or brood production and did effectively suppress the development of chalkbrood disease. Daily chalkbrood mummy production decreased by a factor of 10 in colonies treated with three applications of 6000 mg of lysozyme-HCl when compared with infected, untreated controls and reduced disease symptoms to levels observed in uninfected colonies. Honey production was also found to be significantly negatively correlated with increased disease severity. Lysozyme-HCl shows promise as a new, food-grade therapy for the control of chalkbrood disease in honey bee colonies.