NOSEMA-DISEASE. 51 



In expressing a positive diagnosis the degree of infection could be 

 indicated, for the present at least, by the terms "slight," ''moder- 

 ate," "heavy," and "very heavy." Slight infection by this scheme 

 would indicate that not more than 10 per cent of the bees are infected 

 and that no noticeable loss is to be anticipated from the infection; 

 moderate infection would indicate that from 10 to 35 per cent are 

 infected, that the colony "wdll probably sustain losses from the dis- 

 ease, but that the chances are good for recovery; heavy infection 

 would indicate that from 30 to 60 per cent are infected, that the 

 colony will most Hkely show weakness as a result of the disease, and 

 that it may or may not die; and very heavy infection would indi- 

 cate that more than 60 per cent are infected and that the colony 

 will probably die as a result of the disease. 



While a definite diagnosis in regard to Nosema infection can 

 always be made by laboratory methods (McCray and White, 1918), 

 beekeepers in most instances can diagnose the disease sufficiently 

 well for practical purposes in the apiary. Weakness should cause 

 suspicion. If there is no other obvious cause for the weak condition 

 a strengthened suspicion is justified. If, upon the removal of the 

 stomachs of a few field bees (at least 10 should be examined), some 

 white stomachs are found among them, the presence of Nosema- 

 disease is quite certain. Should there still exist a doubt the organ 

 should be examined further. If the tissues seem to tear easily and 

 when crushed present a milky appearance,^ it may be concluded that 

 the colony is Nosema infected. 



DIFFERENTIAL DIAGNOSIS. 



Dysentery, paralysis, palsy, spring dwindling. Isle of Wight dis- 

 ease. May pest. May sickness, abdominal distension, dry dysentery, 

 dropsy, and disappearing trick are some of the many names which 

 have been appUed to disorders among adult bees. The disorders for 

 which the names have been used have not been sufficiently well 

 defined in all instances, however, to insure their positive diagnosis. 

 From the facts at hand it seems probable that the number of adult 

 diseases is small and that each disease, therefore, from time to time 

 has had more than one name applied to it. It seems equally prob- 

 able that some of the names used have been applied to more than 

 one disease. 



Although little of a definite character is known concerning the 

 disorders of adult bees in general, Nosema-disease is such a definite 

 condition that its differentiation from other disorders should not be 

 difficult. It is the only adult disease that can be diagnosed posi- 

 tively at the present time by laboratory methods. 



I In testing the "milky appearance," crush the suspected stomach between two plates of clear glass. 



