4 rlffh Wisconsin Bulletin 333 



factors that influence European foulbrood. The latter disease 

 is found more or less in all sections of the state, but occurs 

 in a highly virulent form only in certain, areas in the north- 

 west, west, and northeast parts of the state. Sacbrood is more 

 or less sporadic in all parts of the state. 



Bacteria Cause American and European Foulbrood 



Whitei has clearly demonstrated that the three brood dis- 

 eases of bees known as American and European foulbrood and 

 sacbrood are caused by bacteria. The bacteria may be isolated 

 and the disease transmitted in the laboratory as well as in the 

 field. Sacbrood, according to his investigation, is caused by 

 a filterable virus. 



Each disease develops symptoms peculiar to itself; and 

 when these symptoms alone are present, it is not difficult to 

 determine the specific disease. Unfortunately, however, there 

 are several other bacteria which live on the decaying larvae 

 and sometimes cause symptoms similar to those of American 

 foulbrood to occur with European foulbrood and sacbrood. 

 This often leads to confusion not only in the minds of inex- 

 perienced 'beekeepers but to experienced men as well. 



Persons of the widest experience are often misled by some 

 unusual symptoms. The only sure way of determining the 

 kind of disease is through a microscopical examination. If a 

 beekeeper finds diseased brood in a colony and does not know 

 the cause, he should immediately cut out a sample and send 

 it in to the state apiary inspector or to the apiarist at the state 

 experiment station. 



General Symptoms of American Foulbrood 



Sunken cappings often punctured,, together with dead larvae 

 chocolate brown in color, are symptoms of the diseia.se. The 

 larvae cannot be removed from the cell but string out when 

 the attempt is made. When the disease is first introduced into 

 a colony (Fig. 1) the few cells which occur may be overlooked 

 easily. Just after death the larvae are a light coffee color 

 which gradually becomes darker. Finally, when decay is well 

 advanced; the larva loses its shape and melts down. In this 

 stage the mass is quite stringy or ropy. As it dries out a scale 



•White, G. F. — Sacbrood: Bui. 431, U. S. Dept. of Agr 1917 



American Foulbrood: Bui. 809, U. S. Dept. of Aer l<)!>n 

 European Foulbrood:, Bui. 810, U. S .Dept. of Agr.', lllo. 



