6 



CIRCULAR 392, U. S. DEPARTMENT OF AGRICULTURE 



for a considerable period, the colony will be noticeably weakened, 

 and a large proportion of the cells (75 percent or more) will contain 

 dead brood. All weak, infected colonies found during any time of 



Figure 4. — Symptoms of American foulbrood in larvae : A, Healthy larva, lateral view ; 

 B, coiled larva recently dead ; C, healthy larva, ventral view ; D—H, stages in decay and 

 drying of larvae, ventral views. 



year should he burned at once to prevent spread of the disease 

 through robbing. Under no circumstances should colonies be per- 

 mitted to remain in the apiary until they have become seriously 

 ■weakened by or die of American foulbrood. 



