2 BULLETIN 780, TJ. S. DEPARTMENT OF AGRICrLTTJBB. 



from sacbrood. The disease is one, however, of considerable eco^ 

 nomic importance. 



The fact that Nosema-disease is not a new disease deserves em. 

 phasis. The knowledge of the disease and its name only are o: 

 recent origin. Nosema-disease, like the brood diseases, has probablj 

 existed among bees longer than history records the keeping of bees 

 by iflan. Smce the disease is not a new one, fear regarding additiona 

 losses from it would not be justified. On the other hand, as we; 

 know of the disorder, we may entertain the hope that the losses due 

 to it may now be lessened. 



Until 1909 the existence of Nosema infection among bees was not 

 generally known to beekeepers, although it had been studied some- 

 what by Donhoff (1857) about a hah century earlier. Zander began 

 his studies a decade ago and since the appearance of his first paper 

 (1909) a number of investigators have made studies on the disorder. 

 In the papers which have been written concerning the infection, 

 widely differing views regardkig certain points have been expressed, 

 To discuss these different views would be to go beyond the scope o| 

 the present bulletin. 



>/ The writer began the study of Nosema infection in 1910 following 

 the demonstration by him that the disorder exists in the UniteJ 

 States. In pursuing these investigations the object has been no| 

 to devise a treatment for the disease, but rather to ascertain such 

 facts concerning the disorder that the beekeepers might be able to 

 devise methods for its treatment with the assm-ance that they would 

 be not only efficient but also economical. While there is yet much t^ 

 be learned about the disease, this object has been fairly well attained, 

 Relations which the results obtained bear to practical apiculture 

 should be borne in mind, therefore, in reading the paper. i 



During the studies the effect of the disease on colonies and ori 

 apiaries, the transmission of the disease, the resistance of the infectinj 

 germ to heat, drying, sunlight, fermentation, putrefaction, and dis- 

 infectants, and the effect of drugs on the disease are among the 

 problems which have been considered. 



An earher paper (White, 1914) refers briefly to the, nature of the 

 resrflts obtained from these studies. The present bulletin gives all 

 the results obtained from them which are believed to be of direct 

 practical value to the beekeeper or otherwise of particular interesf 

 to him. The natxire of the bulletin is similar, therefore, to the one 

 on sacbrood (White, 1917) recently published.^ 



» As in the sacbrood paper, so in the present one, teclmioal disoupsions have been purposely avoided, 

 The semlteohnical points ,which could not well be omitted are briefly explained in the sacbrood paper! 

 Unless the reader is lamiUar with the nature of such investigations, the sacbrood bulletin wiU probably ba 

 found helpful in following the present one. 



