News — osmia

Mason bees are susceptible to many parasites and diseases, increasing over time, especially when the same nest materials are used for multiple seasons. One of the most destructive diseases of cavity-nesting bees is chalkbrood, which is caused by the fungal pathogen Ascosphaera. Several species of Ascosphaera exist, including Ascosphaera torchioi (affects mason bees), A. larvis, and A. aggregata (affects alfalfa leafcutter bees). Chalkbrood disease also affects honey bees, but it is caused yet another species of the fungus—Ascosphaera apis. Adult bees are not affected by chalkbrood, but they contribute to its spread. Adult masons pick up Ascosphaera spores from flowers and transfer them to the pollen ball they create for their...