262 



AMERICAN BEE JOURNAL 



August 



tively, was the subject of a consider- 

 able number of experiments. The 

 periods it will live in honey, in pollen, 

 and when in the body of dead bees, 

 were also subjects of study. 



The approximate period the germ 

 (Nosema apis) remains alive, in each 

 of the various environments, respec- 

 tively, is as follows : 



Suspended in water, the germ was 

 killed at a temperature of about 136 

 degrees F., in 10 minutes. 



Allowed to dry outdoors, in an 

 empty hive- body, it was dead in 

 about 2 months. Drying at room tem- 

 perature, it lived about the same 

 length of time. 



When dry and exposed to the direct 

 rays of the sun, it was destroyed in 

 from 15 to 32 hours. 



In honey, and exposed to the direct 

 rays of the sun, it was usually de- 

 stroyed by the heat acquired by the 

 honey during the exposure. 



In a 20 per cent honey solution, 

 fermenting at outdoor temperature, 

 it was destroyed in about 9 days. 



In a putrefying suspension, at out- 

 door temperature, it lived more than 3 

 weeks. 



The germ withstood more than one 

 freezing in water. How often it will 

 withstand freezing and thawing has 

 not been determined, and likewise the 

 length of time it will live frozen in ice 

 is not known at the present time. 



In honey, at room temperature, the 

 parasite lived from 2 to 4 months. 



Mixed with pollen, it dies, but lives 

 somewhat longer than when allowed 

 to dry in an exposed environment. 



The germ lived in the body of the 

 dead bees, at room temperature, 

 about 4 weeks, at outdoor tempera- 

 ture about 6 weeks, and at icebox 

 temperature about 4 months. 



In the body of dead bees lying on 

 the soil, in the open, but somewhat 

 protected, it lived from 6 to 10 weeks. 



The temperature is a factor in the 

 environment which has much to '1" 

 with the period Nosema apis will live. 



Spread of Nosema-disease 



Naturally the problem of the spread 

 of Nosema-disease could be complete- 

 ly solved if it were possible to follow 

 the germ (Nosema apis) in nature, 

 during the period it remains alive and 

 outside the living bee. Unfortunately 

 this is well-nigh impossible. Much 

 can be done, however, and already 

 some important determinations have 

 been made. From the studies made, 

 it has been possible to separate the 

 modes of transmission which arc most 

 likely from those which are not so 

 likely. 



By feeding colonies syrup, to which 

 the germ was added, it has been 

 shown that Nosema-disease is pro- 

 duced. The same is true also if water, 

 to which the parasites are added, is 

 given to bees. Nosema infection of 

 bees takes place, therefore, by way of 

 ill. alimentary tract. This fact is es- 

 pecially important in estimating the 

 probable source of infection, in No- 

 sema-disease. 



For purposes of discussion, the 

 problem of the spread of the disease 

 may be classed into 3 subdivisions— 

 the transmission (1) from the dis- 

 eased apiary to the healthy one, (2) 



from the diseased colony to the 

 healthy one in the same apiary, and 

 (3) from the diseased bee to the 

 healthy one in the same colony. 



The question of the spread of No- 

 sema-disease from apiary to apiary, 

 and from one section of the country to 

 another, cannot have the same inter- 

 est to American beekeepers as does 

 the question of the spread of the" 

 foulbroods. This is true because 

 Nosema-disease exists already, it may 

 be said in a general way, in all sec- 

 tions of the United States, and fur- 

 thermore, it probably has had this 

 wide distribution for centuries. From 

 the facts which have been established 

 regarding the period the germ lives in 

 the different environments in which 

 it is likely to be present, the bee- 

 keeper is enabled to estimate, with 

 some degree of satisfaction, the like- 

 lihood of the germ being transmitted 

 from one apiary to another and pro- 

 ducing disease. 



That infection, from one colony to 

 another, occurs is certain, but the ex- 



act means by which it takes place is 

 not entirely known. In the experi- 

 mental apiary the diseased colonies 

 had free access to the flowers of the 

 fields, as did also the healthy ones. 

 In none of the many experiments that 

 were made, from 1912 to 1916, inclu- 

 sive, did Nosema-disease appear in 

 the uninoculated colonies during the 

 active bee season. If it were at all 

 likely that Nosema-disease is trans- 

 mitted by flowers, to an appreciable 

 extent, there would have been a dif- 

 ferent observation to report in this 

 connection. 



Experiments were made, in which 

 brood-frames from Nosema-diseased 

 colonies were inserted, during the ac- 

 tive bee season, into healthy ones, 

 after they had remained out of the 

 hive for a variable length of time. 

 Others were inserted immediately af- 

 ter they were taken from the hive 

 housing a diseased colony. In no in- 

 stance did Nosema-disease appear to 

 any appreciable extent. 



(To be continued) 



G 1 White, in iii hi bacteriologist and the author of several Bulletins of the Bureau of 



I logy, was the first bacteriologist to describe the two kinds of foulbrood, bacillus larvx 



and bacillus pluton. His descriptions of the bacilli of foulbrood are accepted in both hemi- 

 spheres as correct 



