SummaryAn ether extract of honeybee larvae killed byBacillus larvaecontained several volatile organic acids, most of which were also present in an extract from anin vitroculture of the causative organism. The extracts of diseased larvae and the culture were characterized by highly odorous acids, including valeric, isovaleric, anteisovaleric, butyric and caproic acids, whereas healthy larvae were generally devoid of these compounds.