249 



Analytical Considerations, 



Detailed analysis of different degrees of mite infesta- 

 tion has made clear to me that the rate of spread in a 

 colony, apart from normal changes in the bee popula- 

 tion, is itself uncertain. I have already emphasised 

 this, pp. 20-24. This natural phenomenon directly related 

 to the biology of the parasite and governed by external 

 and internal factors, is not peculiar to Acarine disease 

 but general to epidemics. But it emphasises the 

 extreme importance of the early recognition of the 

 presence of the parasite in the seemingly prosperous 

 stocks. When this is done, success in the management 

 of the colony is dependent on good beekeeping as much 

 as anything. This means that beekeepers must be im- 

 pressed with the necessity of obtaining satisfactory 

 examination of their stocks and reports on the same. 



The object of such an analysis is to provide a fair 

 basis on which to make recommendations. In general 

 it is not difficult to forecast the eventual fate of a stock 

 suffering from acarine disease in those cases where the 

 examination has been made because the stock is showing 

 crawling and other symptoms. But it is quite another 

 matter if the discovery has been made upon an ap- 

 parently healthy colony previously unsuspected. In 

 illustration, the time of the year may be early summer, 

 the queen may be young, the season favourable, and 

 the incidence of infestation low and the district fairly 

 clear of disease. While it would not be fair to sell such 

 a stock as healthy or clean, it would not be unreasonable 

 on the part of the owner to endeavour to carry on with 

 it, and I would recommend him, under certain con- 

 ditions, to do so. 



The exact course to be recommended must depend 

 upon the degree and nature of the infestation, i.e., the 

 total percentage of infested bees, and the proportion 

 of these in the different grades, and the condition of the 

 mites, alive or dead. Affected stocks are frequently 

 preponderantly of one type. For example, stocks show- 

 ing no external signs of disease and yet infested are 

 usually mainly of the type Ilia in the foregoing classi- 

 fication. Stocks showing a fairly high percentage, 50 

 or over, mainly in grade Illb., are to be regarded as of 



