DIAGNOSING BEE DISEASES IN THE APIAKY 3 



sition of the dead brood in the cells, (3) color of the dead brood, 

 (4) consistency of the dead brood in different stages of decay, (5) 

 odor coming from the combs, and (6) odor of dead larvae in different 

 stages of decay. 



A chart or guide for use in diagnosing diseases of the brood of 

 bees is given in table 1 (p. 22). 



It should always he kept in mind that more than one hrood dis- 

 ease Tnay he present in a colony. Of first importance at all times is 



Figure 1. — Inspecting combs for brood diseases. A convenient way to hold the comb 

 while looking for dead brood. The arrow indicates the direction of the sun's rays, 

 which should fall on the lower side and bottom of the cells. 



the early discovery of American foulhrood. When a less serious 

 hrood disease is found, it should he determined whether or not Amer- 

 ican foulhrood also is present. 



AMERICAN FOULBROOD 

 CAUSE 



American foulhrood is an infectious disease of the brood of bees 

 caused by a bacterium known as Bacillus larvae. It is the most 

 destructive of the brood diseases, is very infectious, and diseased col- 

 onies practically always die. This bacterium causes the death of 

 larvae and pupae by its growth and multiplication within the 

 stomach. It also causes a typical decay of the dead brood. B. lar- 

 vae resists drying, the action of chemicals, both high and low tem- 

 peratures, and the dehydrating action of honey ; consequently Amer- 

 ican foulhrood cannot be treated successfully except by burning the 

 infected combs and bees. 



