Fig. I. 



The honey bee: a, .Egg; b, 

 young larva; c, old larva; d, 

 pupa. Three times natural size. 

 (U.S. Dept. of Agr. Farm flBul- 

 letin 447.) 



AMERICAN FOULBROOD 



The term "American" is used simply to differentiate this disease from 

 other brood diseases. It does not imply either origin or location of the 

 disease. 



(a) Symptoms 



Appearance of diseased comb. If disease has been present in a 

 colony for some time the comb will assume a mottled or pepper-box 

 appearance. This is caused by open cells containing dead larvae or scales 

 being interspersed with normal brood. This mottled effect is also char- 

 acteristic of other diseases. 



Condition of cappings. Normal healthy cappings are light brown in 

 colour, becoming slightly darker with age. They are somewhat rounded 

 or convex in shape. If a diseased larva or pupa is present in the cell the 

 capping frequently becomes sunken and dark brown in colour. Many 

 cappings are perforated with one or two small holes by the bees as though 

 they were investigating the tardy emergence of the brood. 



Time of death. Death occurs from American Foulbrood almost 

 invariably two days before or two days after the transition to the pupal 

 stage at which time the cells are capped. 



Position in the cell. Larvae lie curled in the cell at the time capping 

 takes place. After the cell is sealed the larva straightens out, lying flat 

 along the bottom of the cell. Three to four days after capping the change 

 to a pupa takes place. It is within two days either before or after this 

 transformation that death occurs. Due to the uniform position in the cell 

 at this time the decaying brood settles in a regular uniform mass, to the 

 bottom of the cell. This characteristic is contrasted to European Foul- 

 brood where the decaying brood is usually twisted in the cell. 



Colour changes. Healthy larvae are pearly white in colour. Decay- 



