704 



GLEANINGS IN BEE CULTUKE 



temperatures that can be used for destroying the 

 germs of the four bee diseases now known to be in- 

 fectious are as follows: 



1. The minimum temperature for European foul 

 brood lies somewhere between 60 degrees C. (140 

 degrees F.) and 65 0. (149 F.), being approximate- 

 ly 63 C. (145.4 F.). 



2. The minimum temperature for American foul 

 brood lies somewhere between 90 degrees C. (194 

 degrees F.) and 100 C. (212 F.), being probably 

 less than 98 C. (208.4 P.). 



3. The minimum temperature for sac brood lies 

 somewhere between 55 degrees C. (131 F.) and 60 

 C. (140 F.), being approximately 58 C. (136.4 F.). 



4. The minimum temperature for nosema disease 

 lies between 55 degrees C. (131 F.) and 60 C. (140 

 F.), being approximately 57 C. (134.6 F.). 



It will be noted, therefore, that 63 degrees C. 

 (145.4 degrees F.) for European foul brood, 98 C. 

 (208.4 F.) for American foul brood, 58 C. (136.4 

 F.) for sac brood, and 57 C. (134.6 F.) for nosema 

 d;!-ease are the approximate minimum temperatures 

 at which the germs of these diseases, respectively, 

 are destroyed. Since there are varying factors in 

 experiments of this nature that tend to produce slight 

 variations in results, these temperatures are referred 

 to as being approximate. It is probable (hat future 

 experiments may cause slight changes to be made in 

 those conclusions. Nothing more than a comparatively 

 slight variation is to be expected, however. In prac- 

 tice the beekeeper, in destroying these germs by 

 heating, will naturally use a quantity of beat some- 

 what in excess of the minimum amount that is ab- 

 solutely necessary. 



Some generalizations may now be made which will 

 be of interest to the beekeeper. The melting-pot 

 of beeswax is between 62 degrees C. (143 6 degrees 

 F.) and 64 C. (147.2 P.), inclusive. It will be 

 observed that this same temperature in ten minutes 

 Mil) destroy the germ causing European foul brood, 

 auo that it is about 10 degrees P. above hat which 

 will destroy the germs of sac brood and nosema 

 disease. A further interesting generalization may be 

 made concerning the heating of honey. Hoi ey when 

 heated to 160 degrees P. reaches a temperature 15 

 degrees P. above the temperature necessary to de- 

 stroy the germ of European foul brood, and about 

 25 degrees P. above the temperature that will de- 

 sijoj the infecting agents of sac brood and nosema 

 disease. The infecting agents of these three diseases 

 of the bee, therefore, will be destroyed when the 

 temperature of 160 degrees P. is used in the com- 

 mercial handling of honey. Finally, it is believed 

 that the results of this work on the the'-'nai death- 

 point of the virases of the bee diseases will be di- 

 lectly applicable to the control of these diseases. 



From the last paragraph it would appeir 

 that the melting-point of wax applied only 

 10 minutes would not be sufficient to kill 

 the germs of American foul brood. As a 

 matter of fact, all beeswax that is used in 

 foundation goes through not less than three 

 separate heatings; and while the tempera- 

 ture is probably never up to 212 (the boil- 

 ing-point of water), yet the separate heat- 

 ings and prolonged i^eriods of heat are suf- 

 ficient to kill all the germs. So far as we 

 know, no case of foul brood has ever been 

 transmitted in foundation. 



Speaking of European foul brood, that 

 disease can be easily killed by a temperature 

 of melting wax if eoutinued for ton minutes. 

 But the temperature at which beeswax is 

 ordinarilv melted when refined is from 180 



(o 190 F. ; and according to Dr. White a 

 temperature of less than 208 F., if applied 

 ten minutes, would do the work. But the 

 ordinary beeswax is kept at 180 to 190 for 

 not less than an hour. The steam is turned 

 off, and the wax slowly cools for 24 hours. 



The ordinary foundation-factory buys its 

 wax in all kinds of shapes and sizes. Some 

 of the cakes are dark, a few of them are 

 almost black, and practically all are off 

 color, and have to be clarified. All of these 

 cakes are put into a large tank holding not 

 less than ten barrels. About a quarter of 

 this bulk is taken up with water. This is 

 heated by means of a jet of live steam, 

 bringing the temperature up to 190 F. The 

 whole mass is kept in a boil for an hour or 

 two, or until it is thoroughly mixed. It is 

 then allowed to stand for 24 hours, gradual- 

 ly cooling. The object of this is to permit 

 all particles of dirt and general foreign 

 matter to settle into the water while the 

 clear wax rises to the top. Just before it 

 comes to a solid state, or when it can still 

 be poured, about 24 hours after turning off 

 the steam, the wax on top is drained off into 

 large pails, and then allowed to cool. 



After the wax has been refined and clar- 

 ified it has to be melted again on hot steam- 

 pipes before it can be sheeted; so that, all 

 told, practically all the beeswax before it 

 goes back to the beekeeper has been sub- 

 jected to three different heatings, covering a 

 total period of 30 hours. This would kill 

 any thing. 



This bulletin rather gives us assuranie 

 that the ordinary bottled honey that has 

 been heated to prevent gTanulation will be 

 rendered free from the germs of European 

 foul brood, and possibly American, al- 

 though this latter is by no means certain. 

 Ordinary honey for bottling is heated to a 

 temperature of 160 degrees at two different 

 times. In all probability the honey is gran- 

 ulated by the time it reaches the bottler. He 

 heats it and runs it off into tanks. It may 

 or may not be allowed to cool; but in order 

 that it may flow freely it is heated again 

 and then sealed while hot. The two separate 

 heatings at 160 for a couple of hours each 

 would probably kill the germs of even Amer- 

 ican foul brood. It might do so entirely. 

 The statement has been made that bottled 

 honey is a frequent source of foul brood 

 because the consumer tlu'ows away the emp- 

 ty bottles. Dr. White's observation wouid 

 give us hope that they are not — eertanily 

 not European foul brood. However, we 

 would never feed bees honey heated to the 

 proper temperature for bottling, an account 

 of the danger of transmitting American 

 foul brood. 



