NOSEMA-DISBASE. 



43 



From the results recorded in Table XXV it is seen that when the 

 dead Nosema-inf ected bees were allowed to remain on the soil exposed 

 to outdoor conditions Nosema apis was virulent at the end of ^ days, 

 but the germ had lost its virulence before 71 days. Results of 

 experiments having the nature of those referred to in this table 

 naturally depend largely upon the climatic conditions which prevail. 



It was observed that insects, ants especially, fed upon the dead 

 bees lying on the ground. In this way they removed much of the 

 material containing the parasites. This fact must be borne ia mind 

 in a consideration of the length of time that bees dead of Nosema 

 disease and lying on the soil might serve as a possible source of 

 infection. 



The five foregoing groups of experiments relative to the period 

 during which Nosema apis remains virulent in the bodies of dead 

 infected bees show that the period yaries with the environment under 

 which the bees are kept, the temperatm-e being an important factor 

 in causing the variation. It is interesting to note that under fairly 

 favorable conditions for its preservation Nosema apis remains 

 virulent within the bodies of dead infected bees only three months, 

 while under less favorable conditions its destruction occurs in a much 

 shorter period. 



INFECTIOUSNESS OF BROOD-COMBS FROM NOSEMA-INFECTED 



COLONIES. 



Experiments have been made for the purpose of obtaining data 

 relative to the likelihood of the transmission of Nosema disease from 

 colony to colony through the medium of brood-combs. Brood- 

 combs on which colonies had died of the disease and ot,hers taken 

 from colonies heavily infected with Nosema apis through experi- 

 mental inoculation were inserted into healthy colonies after different 

 periods of time had elapsed following their removal. Table XXVI 

 gives a summary of experiments made and the results obtained. 



Table lOCVl.— Results from insertion of brood-comhs from Nosema-infected colonies 



into healthy ones. 



Date combs were inserted. 



Period combs 

 were stored. 



Number 

 of combs 



Results of inoculation. 



Apr. 20,1915.. 



Do 



Apr. 26, 1915.. 

 Jiay3,1915... 

 May 19, 1916.. 

 Apr. 26, 1915.. 



Do 



Apr. 24, 1915.. 

 June 18, 1914. 

 June 29,1914.. 

 Apr. 24, 1915.. 

 May 1,1915... 

 Aug. 22, 1914. 

 May 19, 1916.. 



Inserted im- 

 mediately. 



do 



do 



....do 



i month... 

 do.... 



1 month... 



2 months., 

 do.... 



3 months.. 

 ....do.... 



4 months.. 

 6 months. . 



No Nosema infection pro- 

 duced. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 . Do. 



Do. 



Do. 



Do. 



