February, '21] sturtevant: mixed infections 133 



the fact that the queen would tend to desert that section of the comb 

 containing the American foulbrood, particularly where this disease was 

 the primary invader. In many cases one or the other of the diseases 

 will be more prominent, at least in the active stages. This fact may 

 be one of the causes for cases of mixed infection having been overlooked, 

 the beekeeper seeing only the prominent outstanding symptoms. There- 

 fore in cases where there is doubt or suspicion that both diseases may be 

 present in the same colony, a positive laboratory diagnosis often appears 

 to be desirable. 



As is well known, the shaking method of treatment in its essentials 

 is so far the only successful way of treating American foulbrood.' The 

 nature of Bacillus larvae has prevented success along any other line, 

 because of its ability to form exceedingly resistant spores and especially 

 to decompose the dead larva in such a way as to cause the mass contain- 

 ing large numbers of these spores to adhere to the cell wall as if glued. 

 It has been learned furthermore, often by sad experience, that the 

 shaking treatment is practically never successful in the treatment of 

 European foulbrood; in fact, often when used causes the disease to be 

 spread all the more because of the weakening effect the shaking has on the 

 colonies.' The requirements for the successful treatment of European 

 foulbrood have been found to be fundamentally dependent upon ade- 

 quately strengthening the colonies with young bees sufficiently to throw 

 off the disease,' at the same time combined with the requeening of the 

 diseased colonies with vigorous young Italian queens, permitting the 

 bees themselves to remove the infected material. 



The apparent logical solution of the problem of the treatment for a 

 known case of mixed infection, therefore, is to combine the treatments for 

 both American foulbrood and European foulbrood as a single treatment. 

 In other words, the one or more colonies known or strongly suspected 

 to have mixed infection should be shaken as for American foulbrood, 

 requeening them with vigorous young Italian queens and later strength- 

 ening them by the addition of young bees or hatching brood from a 

 healthy colony, or by uniting later. Strength of colony is the important- 

 factor combined with the shaking and requeening with vigorous Italian 

 stock. 



The problem of the control of mixed infections of American foulbrood 

 and European foulbrood is primarily associated with the control of 

 European foulbrood. In localities where both diseases are prevalent 



'Phillips, E. P. 1920. The control of American foulbrood. U. S. Dept. of Agric, 

 Farmers' Bulletin No. 1084. 



'Phillips, E. F. 1918. The control of European foulbrood. U. S. Dept. of Agric, 

 Farmers' Bulletin No. 975. 



