The Occurrence of Diseases of Adult Bees. 



11 



Certain samples have been received in such bad condition as to 

 make examination of any kind impossible. In other instances, sam- 

 ples were received in which the history did not indicate the necessity 

 for laboratory examination. In recent years more care has been 

 exercised in examining all samples of adult bees for the presence of 

 Nosema apis, because of a desire to determine its distribution. The 

 majority of the samples tabulated have been examined by A. P. 

 Sturtevant, apicultural assistant. From 1905 to 1909, previous to 

 the description of Nosema apis, a few samples of adult bees were 

 received, but as at that time no examination was made for this 

 organism, these samples, 14 in all, are not included. 



Distribution by months. — Because of the possibility that Nosema 

 disease is in some manner correlated with the activities of bees, and 

 especially with the character of the food, it is desirable to present 

 data as to the time of year at which the various samples have been 

 received for examination. The dates used are those at which the 

 samples reached the laboratory, which in a few cases might mean 

 that they had been taken from the hives late the month preceding. 



Table 3. — Samples of Nosema disease, by months. 



Month. 



January.. 

 February 



March 



April 



May 



June 



July 



Number 



Number 



Per cent 



of samples 



with 



ofsamples 



examined. 



Nosema. 



infected. 



11 











21 



1 



5 



37 



7 



19 



60 



14 



23 



146 



30 



27 



111 



33 



23 



112 



30 



27 



Month. 



August 



September . 



October 



November. 

 December. . 



Total. 

 Average 



Number 

 ofsamples 

 examined. 



Number 



with 

 Nosema. 



685 



145 



Fer cent 

 ofsamples 

 infected. 



21 



It would appear that there is more of this disease in early summer 

 than at other times, but in some cases at least it is evident that the 

 disease has started during the winter and has not been detected until 

 the bees have become active. Since some samples were sent on re- 

 quest at particular times, the numbers for the several months can 

 not be taken as too definite. 



Geographical distribution. — Table 1 gives the distribution of 45 

 samples of Nosema disease received during the season of 1921. 



The small number of samples of Nosema disease which have so far 

 been diagnosed makes it impossible to draw definite conclusions re- 

 garding the geographical distribution of the disease. Samples have 

 been received from 33 States and from three Canadian Provinces. 

 There is also in the record a sample from Canada without information 

 as to the Province from which it came. 



