SummaryWhen particles of Kashmir bee virus (KBV) and sacbrood virus (SBV) were fed to larvae of the honey bee,Apis mellifera, in Australian colonies, the resulting pupae became in apparently infected. There was no statistically significant difference in the susceptibility of 1, 2, 3 or 4‐day‐old larvae for either virus, but 5‐day‐old larvae were significantly less susceptible to SBV than younger larvae. There was no significant difference in the proportions of pupae that became in apparently infected when, as larvae, they were fed various concentrations of each virus, but significantly more larvae were removed from their cells when fed concentrated preparations of each virus than when fed diluted preparations. Susceptible larvae that became in apparently infected with KBV and SBV developed normally into in apparently infected pupae and later, emerged as in apparently infected work