Stonebrood is a rare fungal disease associated with honey bee brood. It is caused by several different Aspergillus spp. Aspergillus infects the host through the gut if spores are ingested, band also infects through the cuticle. Therefore, adults as well as larvae and pupae can become infected. In addition, most species of Aspergillus produce aflatoxins that have been suggested to be the primary cause of death in stonebrood infected honey bees (Burnside, 1930).
Aspergillus spp. are cosmopolitan filamentous fungi often found in soil, where they thrive as saprophytes, but occasionally they do infect living hosts including, plants, insects and mammals. In addition, the alfatoxins are carcinogenic if inhaled or ingested; therefore precautions need to be taken when stonebrood disease occurs in honey bees principally to protect beekeepers and consumers.
Symptoms observed in colonies with stonebrood are similar to symptoms produced for chalkbrood disease.