1920 



AMERICAN BEE JOURNAL 



339 



Spores of Bacillus larz'ae. 



sume food containing it. Since such 

 food is not fed to the larvae until they 

 are two days or more old, tlie larvae 

 almost always reach the two-day qui- 

 escent period preceding pupation, or 

 have become young pupa;, before 

 death takes place (Fig. S). The dead 

 brood in this disease, therefore, al- 

 most always occupies the endwise po- 

 sition in the cell. 



In American foulbrood there is no 

 sign or symptom known by which one 

 can determine definitely that a larva 

 or pupa is sick until death is very 

 near or has actually taken place. The 

 first symptom to be noticed is that 

 the diseased larva or pupa are slight- 

 ly more opaque than the healthy ones. 

 At this time they are probably dead. 

 During the decay of the dead brood 

 (Fig. S) the outward appearance of 

 the larvae and pupae changes from 

 that of healthy brood to that of the 

 dry scale. This change is gradual and 

 covers a period of a few weeks, vary- 

 ing somewhat with the climatic con- 

 ditions present. 



The bodies of the larvae and pupae, 

 after death, soon soften and the 

 body wall is then easily torn. As the 

 decay continues, the mass becomes 

 viscid, and later so ropy that it can be 

 drawn out into fine threads 2 or 3 

 inches or even more. 



Within a short time after the brood 

 dies it becomes slightly brownish and 

 this color deepens to chocolate, ma- 

 hogany, and coffee shades as the de- 

 cay advances. 



At some time during the course of 

 the disease the characteristic foul- 

 brood odor* occurs in the colony. It 

 is not noticeable early in the disease 

 and is usually not detectable when 

 only a slight mount of disease is 

 present. It tends to disappear from 

 the brood combs when they are re- 

 moved from the bees and, after being 

 cut out of the hive for a considerable 

 period, it ceases to be marked and is 

 often scarcely observable. This fact 

 has contributed somewhat to the mis- 

 understanding that has prevailed in 

 many quarters regarding the odors 

 accompanying the two foulbroods. 

 • The adult bees remove the caps 



from many of the cells containing 

 dead brood (Fig. 5, L, M, Q, R, T). 

 This results in the irregularity in the 

 distribution of the capped and un- 

 capped cells (Fig. 1) so commonly 

 seen in the brood nest. Many of the 

 caps are only punctured (Fig. 5, K) 

 by the bees, while many more remain 

 unaltered (Fig. 5, F). 



The decaying brood masses fre- 

 quently come in contact with the caps 

 and adhere to them if the combs are 

 roughly handled. When the combs 

 are placed in certain positions the 

 viscid masses may pull the caps into 



the cells, resulting in what is spoken 

 of as sunken caps. 



During the early stage of decay, 

 bees remove in a piecemeal fashion 

 portions of the dead brood, leaving 

 remnants (Fig. 5, L) about the brood 

 nest. This symptom is sometimes 

 useful in making an early diagnosis 

 of the disease. Sometimes the bees 

 gnaw slightly the viscid remains and 

 scales. A comparatively small amount 

 of the brood dead of this disease, 

 however, is removed by the bees. 

 Length of Time the Germ Lives 



Since Bacillus larvae is the inciting 



• The odor so frequently mentioned in con- 

 nection with foulbrood has been variously de- 

 scribed, being often compared with that of a 

 glue pot. When once learned it can scarcely 

 be mistaken. It is very distinctive, being un- 

 like any other. The writer, therefore, pre- 

 fers not to attempt to describe it by comparing 

 it with other odors, but to call it simply the 

 foulbrood odor. 



Fig. 6. — American foulbrood. A to E healthy and F to T diseased brood; A, cap over healthy, 

 and F K over diseased brood; G H larvae and I J pupse dead of the disease; Q M R, scales 

 of larv.TE, R being cut lengthwise and N O S T pupa dead of the disease, T being cut length, 

 wise; K, a punctured cap; L, a partially removed larva which died of American foulbrood 

 before reaching the age at which brood is capped. This occurs only occasionally. 



