30 



BULLETIN "TSO, TJ. S. DEPARTMENT OF AGRICULTURE. 



Table VI. — Experiments to determine the heat required to destroy Nosema apis suspended 



in water. ^ 



Date of inoculation. 



Temperature 



Period of 



employed. 



heating. 



°C. 



°F. 



Minutes. 



50 



122 



20 



55 



131 



10 



56 



133 



10 



56 



133 



10 



58 



136 



10 



57 



135 



10 



58 



136 



10 



58 



136 



10 



59 



138 



10 



60 



140 



10 



60 



140 



10 



60 



140 



10 



61 



142 



10 



65 



149 



10 



65 



149 



10 



80 



176 



20 



100 



212 



5 



Results of inoculations. 



Jan. 31, 1913.. 

 Jan. 8, 1913.. 

 Oct. 4, 1913.., 

 Oct. 15, 1913. 

 May 21, 1915. 

 Oct. 15, 1913. 

 Feb. 8, 1913., 

 Oct. 4, 1913.. 

 Aug. 28, 1915 

 Nov. 11, 1912 

 Nov. 20, 1912 

 May 21, 1915. 

 Aug. 28, 1915 

 Nov. 12, 1913 

 Jan. 8,1913.. 

 Oct. 29, 1912. 

 Nov. 12, 1912 



Nosema infection produced. 



Do. 



Do. 



Do. 



Do. 

 No infection produced. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



1 In omitting fractions of degrees the nearest whole number is given. 



From Table VI it will be observed that Nosema apis in a water sus- 

 pension was destroyed in 10 minutes at a temperature somewhere 

 between 135° F. (57° C.) and 138° F. (59° C). 



NOSEMA APIS SUSPENDED IN HONEY. 



From preliminary experiments it was learned that the amount of 

 heating that is required to destroy Nosema apis suspended in glycerin 

 is approximately equal to that required to destroy it when suspended 

 iQ water. It was anticipated, therefore, that the minimum amount 

 of heatiQg that would destroy the germ suspended in honey would 

 approximate that required to destroy it when suspended in water. 



Experiments were made to determine the approximate thermal 

 death point of Nosema apis when it is suspended in honey. In 

 making the experiments the technique used was similar in the main 

 to that of the preceding group of experiments wherein suspensions in 

 water were heated. In Table VII are summarized the experiments 

 performed, together with the results obtained. 



Table VII. — Experiments to determine the heat required to destroy Nosema apis suspended 



in honey. 



Date of inoculation. 



Aug. 28, 1915 

 Aug. 27, 1915 

 June 9, 1915. 

 May 21, 1915. 

 June 8, 1915. 

 Aug. 28, 1915 

 June 9, 1915. 

 Junes, 1915. 

 Mays, 1915.. 

 May 21, 1915. 

 May 21, 1915. 



Temperature 



Period of 



employed. 



heating. 



°C. 



°F. 



Minutes. 



58 



136 



10 



59 



138 



10 



59 



138 



10 



60 



140 



10 



61 



142 



10 



61 



142 



10 



62 



144 



10 



63 



145 



10 



65 



149 



10 



70 



158 



10 



80 



176 



10 



Results of inoculations. 



Nosema infection produced. 



Do. 

 No infection produced. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



