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adversely affected — just to the extent to which bees 

 have been rendered useless to the colony. At the same 

 time the percentage of infestation may be brought to 

 a low level or it may be extinguished. Such a colony 

 may enter winter upon its own stores, but if infestation 

 persist its incidence will tend to rise, and the colony, 

 if alive in spring, is sure to be weakened in numbers. 



In the second case the stock may survive till autumn. 

 A yield of surplus stores is possible, but persistence until 

 spring is improbable. 



In the third instance before the summer is over, the 

 colony becomes disorganised from the high proportion 

 of bees in an advanced stage of the disease, and dies 

 out. 



These facts show the fundamentally important place 

 of the queen in relation to this disease. Apart from 

 the fact, already demonstrated, that she herself may 

 contract infection and thus constitute a double danger, 

 viz., a source of infection to her bees, and a failure in 

 production owing to progressive weakness, the absolute 

 necessity for a high rate of increase ought to be evident. 

 Consequently the value of timely re-queening in relation 

 to the main honey flow has special significance in 

 relation to disease, assuming that a first class selection 

 both for vigour and fertility is made. 



Seasonal Variations in Incidence. 



Tarsonemus woodi breeds all the year round, and 

 migrations from bee to bee are also continuous through- 

 out the year. 



Very far reaching results follow from this fact. We 

 have already seen that of the circumstances which tend 

 to counteract the spread of Aoarine Disease in the 

 working season, the most important is the rapidly 

 changing character, both in individuals and numbers 

 of the summer bee population. In winter, by contrast, 

 we have a population in which normally such changes 

 do not occur. The winter population is static, not 

 kinematic. 



In relation to this, winter is a distinctively critical 

 period to a stock harbouring Tarsonemus woodi, and 

 the circumstances favour a steady spread of the disease. 



