398 



Beekeeping 



pickled brood. These diseases weaken colonies by reducing 

 the number of emerging bees needed to replace the adult bees 

 which die from natural causes. The adult bees are not known 

 to be affected. The larvae dead of these diseases show cer- 

 tain differences in appearance which are useful in determin- 

 ing which disease is present. These diseases are entirely 

 distinct, as shown by these differences in appearance, by 

 differences in response to treatment, by differences in 

 the age of the larvae affected and by bacteriological ex- 

 amination. There is no evidence that chilled or starved 



brood develops 

 into an infectious 

 disease or that 

 dead brood favors 

 the development 

 of an infectious 

 disease. 



FIG. 163. American foul brood : a, b, f, normal sealed cells ; c, j, sunken 

 cappings, showing perforation ; g, sunken capping not perforated ; h, I, 

 m, n, q, r, larvae affected by disease ; e, i, p, s, scales formed from dried- 

 down larvae ; d, o, pupae affected by disease. Twice natural size. 



American foul brood. 



This disease (Fig. 163) is frequently called simply "foul 

 brood/' It usually shows itself in the larvae just about the 

 time that they fill the cells and after they have ceased feed- 

 ing and have begun pupation. At this time the larva is 

 sealed over in the comb (Fig. 163, a, 6, /). The first outward 

 indication of the infection is a slight brownish discoloration 

 and the loss of the well-rounded appearance of the normal 

 larva (Fig. 163, I). The larva gradually sinks down in the 

 cell and becomes darker in color (Fig. 163, h, m) and the 

 posterior end lies against the bottom of the cell. Frequently 



