Carbon Dioxide Activation of Spores of the Chalkbrood FungusAscosphaera Apis

SummaryCarbon dioxide has been shown to be important for the activation of spores of A. apis. About half the spores under test were activated at less than 5% CO2 in air, while at 12·5% CO2, virtually all spores were activated. Ten minutes' exposure to 10% CO2 in air was sufficient to initiate activation. Larval respiration produces CO2, and thus larvae must initiate the activation of spores with which they come into contact.