6 CIRCULAR 39 2, 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 weah, infected colonies found during any time of 



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

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

 drying of larvae, ventral views. 



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

 through rohhing. Under no circumstances should colonies he per- 

 mitted to re^nain in the apiary until they have hecome seriously 

 weakened hy or die of American foulhrood. 



