GAMMA RADIATION INACTIVATION OF BACILLUS LARVAE TO CONTROL AMERICAN FOUL BROOD
M. A. Z. HORNITZKY AND P. A. WILLS
The radiation dose required to prevent the spread of American foul brood disease in honeybees (Apis mellifera) was investigated quantitatively. Scales from infected combs were gamma-irradiated at different doses and the number of Bacillus larvae spores surviving treatment determined. At least 99'99994% of spores were inactivated by a dose of 1 Megarad (Mrad). The decimal reduction dose for spores in scale was estimated as 0'162 ± 0'014 Mrad; the disease did not develop in hives containing heavily infected frames which had been treated with a minimum dose of 1 Mrad. The basis for selecting the radiation dose required to decontaminate infected hives is discussed. Estimates of costs indicate that substantial savings are possible if irradiation treatment replaces the destructive control method currently used.