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CIRCULAR 3 9 2. U. S. DEPARTMENT OF AGRICULTURE 



APPEARANCE OF THE DEAD BROOD 



A larva killed by a fungus becomes noticeably harder soon after 

 it dies, and the glistening white changes to a dull creamy white. 

 Later the dead larva becomes shrunken and wrinkled. The head 

 end of a larva- that dies after it has straightened out in the cell 

 dries most rapidly and often curves upward at first but later tends to 

 straighten out again (fig. 15). The fungus soon grows through the 

 skin in a ring just back of the head and forms a sort of white collar. 

 Within 1 or 2 days the fungus grows over the entire larva and forms 

 a false skin which clings closely to the true skin. The color at this 

 stage is chalky white. The fungus produces spores on the outer 

 surface of the dead larva, and the white changes to a shade of green, 

 black, or other color, corresponding to the color of the spores. 

 Spores form earliest and most abundantly near the head end of 



Figure 16. — Dead brood (mummies) killed by a pathogenic fungus. 



dead larvae. The color of the spores deepens as they mature and 

 fades as they become old and dry. After dead larvae and pupae 

 have become dry they are known as mummies (fig. 16). In Europe 

 the disease of bees caused by Aspergillus flavus is called "stone brood" 

 on account of the hard texture of the dead brood. 



DISEASES OF ADULT BEES 



WHAT TO OBSERVE WHEN LOOKING FOR DISEASES OF ADULT 



BEES 



Xo general rules can be given for the diagnosis of diseases of 

 adult bees. Such diagnosis is made more difficult by the fact that 

 at any time of the year many bees may die as a result of old age 

 or abnormal conditions. Symptoms of the different diseases over- 



