42 BULLETIN 780, U. S. DEPAKTMENT OF AGRICULTURE. 



AT REFKIGERATOR TEMPERATURE. 



In Table XXIV are summarized experiments the results of which 

 indicate the approximate period during which Nosema apis remains 

 virulent in the bodies of infected bees kept at refrigerator temper- 

 ature. 



Table XXIV. — Resistance of Nosema apis in dead bees drying at refrigerator temperature. 



Date of inoculation. 



Period in 

 refrig- 

 erator. 



Results of inoculation. 



Mar. 4, 1916. 

 Mar. 20, 1916 

 Mar. 20, 1916 

 Apr. 22,1916. 

 May 6, 1916.. 

 Dec. 7,1915. 

 Jan. 7, 1916.. 

 May 24, 1916. 

 Junes, 1916. 

 Feb. 10, 1916 

 Apr. 7, 1916. 

 May 6, 1916. 

 July 3, 1916., 



Months. 

 2 

 2 

 2i 

 3 

 3i 

 3 

 4 

 4 

 4 

 5 

 6 

 8 

 10 



Nosema infection produced. 



Do. 



Do. 



Do. 



Do. 

 No infection produced. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



The results recorded in Table XXIV show that Nosema apis in 

 the bodies of dead infected bees remained virulent at refrigerator 

 temperature from two and a half to four months. 



ON THE SOIL. 



Dead Nosema-infected bees were placed on the soil in the open, 

 but in a somewhat shaded spot. After different intervals of time 

 colonies were inoculated, these dead bees being used as the source 

 for the infective material. Table XXV summarizes the experi- 

 ments performed, the results of which indicate the approximate 

 period during which Nosema apis remains virulent in the bodies of 

 dead bees lying on the soil. 



Table XXV. — Resistance of Nosema apis in dead bees lying on the soil. 



Date of inoculation. 



Period 

 on soil. 



Results of inoculation. 



July 16, 1915. 

 Aug. 1, 1916. 

 Aug. 28, 1915 

 Aug. 12, 1916 

 Aug. 26, 1916 

 Aug. 28, 1915 

 May 14, 1916. 

 Oct. 4, 1915.. 

 Oct. 21, 1915. 

 Oct. 21, 1915. 

 Oct. 4, 1915.. 

 Nov. 9, 1915. 



Days. 

 13 

 18 

 25 

 29 

 43 

 44 

 71 

 77 

 85 

 94 

 104 

 104 



Nosema infection produced. 



Do. 



Do. 



Do. 



Do. 



Do. 

 No infection produced. 



Do. 



Do. 



Do. 



Do. 



Do. 



