2 BULLETIN" 180, U. S. DEPARTMENT OF AGRICULTUEE. 



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 of 

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

 existed among bees longer than history records the keeping of bees 

 by man. Since the disease is not a new one, fear regarding additional 

 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 mfection among bees was not 

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

 what by Donhoff (1857) about a half 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 regarding certain points have been expressed. 

 To discuss, these different views would be to go beyond the scope of* 

 the present bulletin. 



The writer began the study of Nosema infection in 1910 following 

 the demonstration by him that the disorder exists in the United 

 States. In pursuing these investigations the object has been not 

 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 assurance that they would 

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

 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. 



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

 apiaries, the transmission of the disease, the resistance of the infecting 

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

 results obtained from these studies. The present bulletin gives all 

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

 practical value to the beekeeper or otherwise of particular interest 

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

 on sacbrood (White, 1917) recently published.^ 



1 As in the sacbrood paper, so in the present one, technical discussions have been piirposely avoided. 

 The semitechnical points which could not well be omitted are briefly explained in the sacbrood paper. 

 Unless the reader is familiar with the nature of such investigations, the sacbrood bulletin will probably be 

 found helpful in following the present one. 



