4 Department Circular 28$, U. S. Dept. of Agriculture 



Professor Jones (15) we learned that in every case water used with the 

 formalin gave just as good results as when alcohol was used. The assistant 

 apiarist, Mr. Jarvis, also substantiated these conclusions. 



In a recent article G. L. Jarvis (IS), of the Ontario Agricultural 

 College, Guelph, Ontario, describes results of experiments in the 

 apiary in collaboration with Doctor Jones concerning the effective- 

 ness of water-formalin and alcohol-formalin solutions. Colonies 

 made with 2-pound packages of bees were used in which to test 

 combs treated in various ways. He says: 



From the results of these experiments and laboratory tests we have arrived 

 at these conclusions : First, that both the formalin water and alcohol formalin 

 solution will kill all germs causing American foulbrood in open cells. Sec- 

 ond, that there is still a doubt as to the effectiveness of both solutions in the 

 case of capped cells. 



With this in mind, we are ready to advocate the use of the formalin water 

 solution for sterilizing super combs from diseased colonies after the honey has 

 been extracted. The strength of the solution must not be less than 15 per 

 cent formalin to 85 per cent water and the combs immersed for at least 12 

 hours. The uncapping must be well done ; that is, there must be practically 

 no sealed honey in the combs. The combs should be held, if possible, until the 

 following spring before being given back to the bees. 



Although in our experiments so far we have had no reappearance of 

 disease in treated brood combs, except in check colonies, some other bee- 

 keepers who have tried the alcohol-formalin treatment have not been so suc- 

 cessful. However, the super comb is the doubtful comb, and we believe it is 

 well worth while to know of a cheap solution, such as the formalin-water, 

 which will eliminate this doubt. Again, if all combs from a diseased colony 

 were melted or burned there would be approximately three super combs de- 

 stroyed to every brood comb, and the super combs would likely average a better 

 quality than those in the brood chamber. 



G. H. Vansell, in California (23), recently has reported promising 

 experiments in sterilizing foulbrood combs, in which he used various 

 mixtures of formalin in soapy waters. The results were found 

 encouraging as to sterility and cost. No details are given concerning 

 methods or results. 



Since the announcement of this new method of treating combs 

 many beekeepers, as well as the investigators cited above, have been 

 stimulated to experiment for themselves. In 1924, 33 samples of 

 treated comb were submitted by beekeepers to the Bee Culture Labo- 

 ratory for cultural examinations as to the sterilizing efficiency of 

 the various solutions used. In a majority of cases the disinfectant 

 used was not described. In about one-third of the cases some varia- 

 tion of the alcohol-formalin solution as devised by the person 

 sending the sample was used. Three of these cases, however, were 

 specifically said to have been treated with the commercial alcohol- 

 formalin solution. Of the 33 samples, 10 gave cultures showing 

 growth of Bacillus larvae from both open and sealed cells. Four- 

 teen of the 33 samples, including 2 samples that had been treated in 

 the commercial solution, gave cultures showing no growth from open 

 cells but good vegetative growth of B. lawae from many of the sealed 

 cells. Nine of the 33 samples, only 1 of which was known to have 

 been treated with the commercial solution, gave cultures showing no 

 growth from either open or sealed cells, thereby indicating complete 

 sterilization. 



It would, therefore, seem probable that, although the method of 

 treating infected brood combs with an alcohol-formalin solution is a 

 step in advance in the control of American foulbrood, there apparently 







