Circular No. 79. 



United States Department of Agriculture, 



BUREAU OF ENTOMOLOGY, 

 L. O. HOWARD, Entomologist and Chief of Bureau. 



THE BROOD DISEASES OF BEES. 



By E. F. Phillips, Ph. D., 

 In Charge of Bee Culture. 



In view of the widespread distribution of infectious brood diseases 

 among bees in the United States, it is desirable that all bee keepers 

 learn to distinguish the diseases when they appear. It frequently 

 happens that an apiary becomes badly infected before the owner real- 

 izes that any disease is present, or it may be that any dead brood 

 which may be noticed in the hives is attributed to chilling. In this 

 way disease gets a start which makes eradication difficult. 



There are two recognized forms of disease of the brood, designated as 

 European and American foul brood, which are particularly virulent. 

 In some ways these resemble each other, but there are certain distin- 

 guishing characters which make it possible to differentiate the two. 

 Reports are sometimes received that a colony is infected with both 

 diseases at the same time, but this is contrary to the experience of 

 those persons most conversant with these conditions. While it may 

 be possible for a colony to have the infection of both diseases at the 

 ^me time, it is not by any means the rule, and such cases are probably 

 not authentically reported. Since both diseases are caused by specific 

 bacilli, there is absolutely no ground for the idea held: by some bee 

 keepers that chilled or starved brood will turn to one or the other of 

 these diseases. Experience of the best practical observers is also in 

 keeping with this. For a discussion of the causes of these diseases the 

 reader is referred to Technical Series, No. 14, of the Bureau of Ento- 

 mology, "The Bacteria of the Apiary, with Special Reference to Bee 

 Diseases," by Dr. G. F. White. 



AMEEIOAN FOUL BEOOD. 



American foul brood (often called simply "foul brood") is dis- 

 tributed through all parts of the United States, and from the symptoms 

 published in European journals and texts one is led to believe that it is 

 also the prevalent brood disease in Europe. Although it is found in 

 almost all sections of the United States, there are many localities 

 entirely free from disease of any kind. 



The adult bees of an infected colony are usually rather inactive and 



do little toward cleaning out infected material. When the larv^ are 



first affected they turn to a light chocolate color, and in the advanced 



stages of decay they become darker, resembling roasted coffee in color.- 



5947—09 



