2 OCCURRENCE OF BEE DISEASES IX THE UXITED STATES. 



the men .supplj'ing- the .sumple.s. The records are here made only hy 

 counties, and it is believed that no bee keeper will consider this a 

 betrayal of confidence. 



In making records it was necessary to consider a county as a unit. 

 It is impracticable for the bureau to work with units smaller than 

 counties. A count}' is i-ecorded as containing- disease when the first 

 sample of diseased brood has been received from that count}'. In most 

 cases, however, several samples have been received from the counties 

 recorded as having disease present. A considerable experience in the 

 examination of infected apiaries indicates that it is usually safe to 

 assume that disease is more widespread than is recognized by even the 

 best bee keepers. 



From the extent of the work it is obvious that most of these data 

 were obtained by correspondence. No claim i^ made that all of these 

 counties have been visited. It did not seem advisable to accept 

 reports of the existence or nonexistence of disease, but to make 

 positive records only on the receipt of a sample of diseased brood for 

 examination. It frequently happens thtit letters are receiv^ed stating 

 that no disease has ever occurred in the count}' when samples of dis- 

 eased brood have already been received in considerable numbers, and 

 in some cases after personal examination has shown disease to be prev- 

 alent. Furthermore, an infectious disease is often mistaken for chilled 

 brood or so-i-alled pickle brood, or vice versa. All samples recorded 

 as containing disease were diagnosed in the bacteriological laboratory 

 of the bureau. This work has been done by Dr. G. F. White, expert 

 in bacteriology, and Mr. A. II. McCray, apicultural assistant. In all, 

 about 1,800 samples have heen examined. 



It seems advisable to list certain counties as "suspected." From 

 these counties satisfactory samples have not been received. A county 

 is marked ''suspected'"' when the l)ureau is informed of the presence 

 of disease by an apiary inspector or by some beekeeper who is be- 

 lieved to be conversant with disease. The majority of such reports 

 from bee keepers have not been accepted as satisfactory evidence even 

 for marking a county "suspected.'' In some cases such a record is 

 made ""suspected*' if the result of an examination strongly suggests 

 the presence of disease, but is not conclusive. In no case is a county 

 marked as suspected merely because of its proximity to known disease. 

 If this were done the list would be greatly increased. 



In case a bee keeper lives in one county and his post oflSce is in 

 another the sample received may in some cases be attributed to the 

 wrong county. This source of error was not taken into consideration 

 in the earlier work, but now the bureau asks the sender of a sample to 

 give the town or township and county in which the apiary is located. 

 Another possibility for error is in the changes in county boundaries. 



[Cir. 138] 



