DIAGNOSING BEE DISEASES IN THE APIARY 



APPEARANCE OF THE COMBS AND CAPPINGS 



In healthy brood combs, where a normal queen has been laying, there 

 is a certain regularity in the arrangement of areas containing eggs, 

 larvae, pupae, and emerging bees and the cappings are convex and 

 uniform in appearance (fig. 1, A). In a colony infected with Ameri- 

 can foulbrood the brood is more or less irregularly arranged, depend- 

 ing on the degree of infection. Great irregularity, due to the 

 intermingling of cells of healthy brood with uncapped and capped 

 cells of dead brood and cells with punctured and sunken cappings, 

 is sometimes spoken of as the "pepperbox" appearance. Dead brood 

 in cells with discolored, sunken, or punctured cappings (fig. 1B,C,D) 

 should always be studied carefully to determine whether death was 

 caused by American foulbrood. 



In advanced stages of the disease many of the cappings are punc- 

 tured. Cappings may also be broken away at the edge and settled 

 down on the dead brood, appearing dark brown and shining. 

 Cappings over dead brood are often removed by adult bees, and in 

 advanced cases many dried scales, as the remains of dead larvae and 

 pupae are then called, can be seen in uncapped cells (fig. 1 E and F). 



SYMPTOMS SHOWN BY THE DEAD BROOD 

 KIND AND AGE OF AFFECTED BROOD 



Usually only worker brood is affected, but occasionally drone and 

 queen brood are also killed. Adult bees are never affected by this 

 disease. 



Death occurs quite uniformly after the larvae have been capped 

 over, have spun their cocoons, and are fully extended on the floor of 

 the cells, as shown by the healthy larvae in figure 1, 6?, and 2, A. 

 Occasionally death occurs after the pupa has formed but before the 

 body (except the eyes) is pigmented. (See healthy pupae in figs. 

 3, A, and 4, A.) In advanced cases a few larvae may die while coiled 

 on the bottom of the cells (fig. 2, B), but only rarely does death occur 

 when larvae are irregularly twisted on the side walls. Larvae killed 

 by American foulbrood that are coiled or irregularly twisted often 

 show symptoms similar to those of European foulbrood, and a labor- 

 atory examination may be necessary to determine whether the latter 

 disease also is present. 



COLOR AND CONSISTENCY OF THE DEAD BKOOD 



Soon after death the glistening white color of healthy larvae and 

 pupae changes to dull white. About 2 weeks after death the color 

 is very light brown, and the well-rounded appearance is lost. The 

 dead brood gradually sink in the cells during decay and become darker 

 (figs. 1 to 4), changing from a light coffee color to dark chocolate 

 brown by the end of the fourth week. Scales are very dark brown or 

 nearly black. The decay and drying of dead brood ordinarily re- 

 quire a month or more. Scales are difficult to distinguish in old brood 

 comb, since they are about the same color as the comb; but in new 

 comb they are readily distinguished. 



