CONTROL OF ETTROPEAN FOTJLBROOD. 5 



I manifestations of one disease, or that European foulbrood changes 

 to American foulbrood. Such is not the case. It is therefore essen- 

 tial that the symptoms be studied with great care, since to treat 

 American foulbrood by methods applicable only to European foul- 

 brood will result in the spread rather than in the eradication of the 

 disease. 



(1) Age of larvce affectea. — European foulbrood usually attacks 

 the larva at an early stage of its development, while it is still curled 

 up at the base of the cell (fig. 1, E). At the time of the first mani- 

 festation of disease the larva is about three days old, from the 

 hatching of the egg. A very small percentage of larvae die after 



Fig. 1. — Portion of comb showing the effect of European foulbiood 

 upon the larvae: a,j,k, Normal sealed cells; b,c,d, e, g, i, I, m, p, g, 

 larvse affected by disease; r, normal larva at age attacked by disease- 

 /, liinfOf dried^down larvae or scales. Three times natural size. 



capping, but sometimes quite young larvae are attacked (fig. 1, E, M) . 

 Sunken and perforated cappings, which are such common symptoms 

 of American foulbrood, are sometimes seen in colonies suffering with 

 European foulbrood. 



(2) Early sym/ptoms. — The earliest indications of the disease are 

 a slight yellow or gray discoloration and the uneasy movement of 

 the larva in the cell. The larva loses its well-rounded, opaque ap- 

 pearance and becomes slightly translucent, so that the tracheae may 

 become prominent (fig. 1, B), giving the larva a clearly segmented 

 appearance. 



(3) Position of larnw. — The larva may be flattened against the 

 base of the cell, may turn so that the two ends are to the rear of the 

 cell (fig. 1, P) , or may fall away from the base (fig. 1, E, G, L) . The 



