NOSBMA-DISEASE. 



37 



RESISTANCE OP NOSEMA APIS TO DIRECT SUNLIGHT. 



RESISTANCE WHEN DRY. 



Petri (dishes (fig. 6) which were smeared with the cnished stomachs 

 of Nosema-iofected bees were exposed to the direct rays of the sxm. 



Fig. 6.— Open Petri dish. One-half of the dish, either top 

 or bottom. 



After intervals reckoned ia hours healthy colonies were inoculated 

 with a suspension made from the dishes which had been 0?:posed. 

 Table XVIII summarizes the experiments and the results obtained. 



Table XVIII. — Resistance of Nosema apis when dry to direct sunlight. 



Date of inoculation. 



Period of 

 exposure 

 to sun. 



Results of inoculation. 



Aug. 2, 1915.. 

 Aug. 21, 1914. 

 Aug. 2, 1915. 

 July 28, 1915. 

 Aug. 27,1914. 

 Aug. 23,1915. 

 Aug. 20, 1915. 

 Sept. 2, 1914.. 

 Aug. 25, 1915. 

 Sept. 3, 1914.. 

 Sept. 14, 1915. 

 Aug. 17,1915. 

 Sept. 10, 1915. 

 Aug. 19, 1915. 

 ,Sep1,. 11, 1916. 

 Aug. 24,1914. 

 SSot. 13,1915. 

 Aug. 4, 19141. 

 Sept. 16, 1915. 



Hours. 



2 



5 



5 



8 



10 



13 



15 



16 



,. 17 



20 



29 



15 



. ,17 



18 



21 



22 



32 



' 34 



35 



Nosema infection produced. 



Do; 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 • Do. 



Do. 



Do. 

 No infection pi^oduced. 



Do. 



Do. 



Do. 



Do. 



Do. . , 



Do. 



Do. 



The results in Table XVIII show that ,Noserm apis was destroyed 

 in the experiments recorded ia from 15 to 32 hours' exposure to direct 

 sunlight. 



It will be readUy appreciated that, the time that Nosemct apis will 

 resist the destructive effects of the sun's rays wiU vary largely accord- 

 ing to .the intensity of the rays, the heat present, ?,nd the thickness of 

 the layer of infective material exposed. 



' DESTRDCTION IN WATER. 



In experiments made for the purpose of determiriitig the time re- 

 quired to destroy Nosema apis suspended in water, an aqueous 

 suspension of the crushed stomachs of about 10 bees was poured into 

 each of a number of Petri dishes (fig. 6) and exposed to the direct 



