20 CIRCULAR 3 92, U. S. DEPARTMENT OF AGRICULTURE 



THE SCALES 



Scales of larvae dead from saebrood can be removed from the cells 

 with ease. They are dark grayish brown, or nearly black, and are 

 hard and brittle with the head end turned sharply upward. The 

 outline may be somewhat wavy. The back or lower surface is smooth 

 and polished, while the upper surface is rough and somewhat con- 

 cave. The lower surface takes the form of the cell walls and gives 

 the entire scale a boatlike appearance often referred to as gondola- 

 shape or like a Chinese shoe. 



Infection With Two or More Brood Diseases 



In localities where two or more brood diseases are prevalent, more 

 than one brood disease will occasionally be found in the same colony 

 or even in the same comb. So far as is known a single larva is 

 never affected by more than one disease. When American foulbrood 

 is found in the same comb with European foulbrood or saebrood, 

 usually one of the diseases will be more prominent, at least in the 

 active stages, which may cause the mixed infection to be overlooked, 

 the beekeeper seeing only the most prominent symptoms. In cases 

 where there is doubt or a suspicion that more than one disease may 

 be present in the same colony, a laboratory diagnosis is desirable to 

 prevent improper treatment. Since American foulbrood is the most 

 serious, a careful search for this disease should ahvays he made even 

 when another disease is knoiv to be present. 



Table 1 gives in summary form the characters differentiating the 

 principal brood diseases. 



Fungus Diseases of Brood 



causes 



In addition to the diseases previously described, diseases of the 

 brood of bees are caused by several different fungi. The most com- 

 mon of these are species of Aspergillus. In this country A. flavus 

 attacks brood more frequently than other fungi. In Europe a fun- 

 gus known as Pericystic apis causes a disease of brood known as 

 "chalk brood." This fungus does not occur in North America. 



IMPORTANCE 



Normally only slight losses of brood are caused by fungus dis- 

 eases. The small amount of brood that is killed is removed promptly 

 by the worker bees and is rarely noticed by the beekeeper. Brood 

 is most likely to become infected when moisture collects in the hive 

 late in the winter and early in the spring, permitting fungi to grow 

 over the combs. 



AGE OF BROOD AND RACES OF BEES AFFECTED 



Brood of all ages, and also adult bees, are susceptible to fungus 

 diseases. After the feeding period is passed, however, and the cells 

 have been capped, brood is less likely to become infected. All the 

 races of bees common in this country are susceptible. 



