DIAGNOSING BEE DISEASES IN THE APIABY 19 



SYMPTOMS 



APPEARANCE OF THE COMBS 



In colonies with sacbrood the brood is slightly irregular. Scat- 

 tered here and there among the healthy brood are cells containing 

 dead brood (fig. 12). The capping-s over dead brood are first punc- 

 tured and later removed by the bees. The holes vary in size, and 

 occasionally there is more than one. Sometimes the size and uniform 

 shape of the hole indicate that the cell has never been completely 

 capped. Dead larvae usually lie fully extended on the floor of the 

 cell (fig. 13, B-F), showing the dark-brown heads through the 

 openings (fig. 12). When these conditions are present the dead 

 larvae should be studied carefully. 



Figure 13. — Sacbrood : A, Oral view of healthy larva at the age when death usually occurs 

 from sacbrood ; B—F, stages in decay and drying of larvae dead of sacbrood. 



AGE OF AFFECTED LARVAE 



Death from sacbrood almost always occurs after the cell is capped 

 and the larva has spun its cocoon and is motionless. At this stage 

 the larva is fully extended on the floor of the cell. In heavily 

 infected colonies a few coiled larvae may be killed. 



COLOR AND ODOR OF THE DEAD BROOD 



Shortly after death caused by sacbrood the color of the larva 

 changes from the pearly white to a slightly yellowish color. This 

 gradually becomes darker, beginning with the head and front third 

 of the larva, which soon changes to a brown or grayish brown and 

 later a dark brown. Scales are almost black for the entire length, 

 the head end usually being darkest. 



