TxvEATMEisT OF BEE DISEASES. i 



majority of the reports of wax-moth depredations received by this 

 department which can be investigated it is found that the trouble is 

 actually an outbreak of a brood disease. 



The spraying of fruit trees while in bloom is possibly injurious to 

 bees, and there exists among beekeepers a strong feeling against the 

 practice. Since no entomologist now recommends that fruit trees be 

 sprayed during the blooming period, this is probably rarely done by 

 progressive fruit growers. However, it is frequently reported by 

 beekeepers that they are losing bees by poisoning due to spraying. 

 A number of cases of the death of colonies, reported as caused by 

 poisoning due to spraying while trees were in bloom, have been found 

 to be in reality outbreaks of European foul brood, which is particu- 

 larly prevalent in the spring and early summer. 



Other circumstances to which is often attributed the death of brood 

 or of the colony are chilling, fumes from coke ovens, and malicious 

 poisoning. The wise attitude on the part of the beekeeper is j&rst to 

 suspect diseases as being the cause of any losses which he may sus- 

 tain, and to be sure that there is no infectious disease present before 

 looking elsewhere for a cause. 



NATTJUE OF THE BISEASES. 



There are two recognized infectious diseases of the brood of bees, 

 now known as American foul brood and European foul brood. Both 

 diseases weaken colonies by reducing the number of emerging bees 

 needed to replace the old adult bees which die from natural or other 

 causes. In neither case are adult bees affected, so far as known. The 

 means used by the beekeeper in deciding which disease is present is the 

 difference in the appearance of the larvse dead of the two diseases. 

 That the diseases are entirely distinct can not now be doubted, since 

 they show certain differences in the age of the larvse affected, in their 

 response to treatment, and in the appearance of the dead larvae. 

 This is made still more certain by a study of the bacteria present 

 in the dead larvae. Eeports are sometimes received that a colony 

 is infected with both diseases at the same time. Wliile this is pos- 

 sible, it is not by any means the rule, and such cases are usually 

 not authentically reported. There is no evidence that chilled or 

 starved brood develops into an infectious disease or that dead brood 

 favors the development of a disease. 



ITAMES OE THE DISEASES. 



The names American foul brood and European foul brood were 

 applied to these diseases by the Bureau of Entomology, of this de- 

 partment, to clear up the confusion in names which formerly existed. 

 By retaining the words " foul brood " in each name the disease- 

 inspection laws then in force could be interpreted as applying to 



442 



