EXPERIMENT STATION BULLETINS. 305 



are different. Recent investigators have demonstrated the possibihty that 

 the disorder is caused by a mite which occupies the tracheae or breathing 

 tubes of the bee, thereby shutting off air circulation. The disease is not con- 

 sidered serious in Michigan. 



Necessary Precautions. 



"An ounce of prevention is worth a pound of cure." The beekeeper can 

 often save himself much trouble and expense by preventing disease from 

 getting a foot-hold in his apiary. 



Never feed honey — unless you are absolutely sure it is not infected — 

 without diluting one-half and boiling in a closed vessel for twenty minutes. 



Never purchase bees from anyone without inspection by a competent per- 

 son or else with inspector's certificate attached. 



Never allow a weak or dead colony to be robbed out. It may be diseased. 

 Contract the entrance of weak colonies to one bee-way in robbing season. 



If you attempt to winter diseased colonies, if at all possible winter them 

 in the cellar where they can not be robbed out in early spring if they die in 

 winter. 



If you winter outdoors see to it that all colonies not defending their en- 

 trance in early spring are closed to prevent robbing. 



The use of old combs and second hand apparatus of all kinds is dangerous. 



Never expose sweets of any kind during the robbing season. If robbing 

 is once started your bees may visit diseased colonies in the neighborhood. 



Be on the watch continually for symptoms of disease in your apiary. 



Bibliography. 



1. Phillips, E. F. 



1916. Treatment of Bee Diseases. 



2. Sturtevant, A. P. 



1920. A Study of the Behavior of Bees in Colonies Affected by 

 European Foul-brood. 



3. White, G. F. 



1912. The Cause of European Foul-brood. 



4 



1917. Sac-Brood. 



5 



1919. Nosema Disease. 



6 



1920. American Foul-Brood. 



7 



1920. European Foul-Brood. 



