GLEANINGS IN BEE CULTURE 



April, 1917 



across the board in such a way that the 

 edge comes fiush with the side of the hole in 

 the escape. This gives th© bees a foothold. 

 If desired, the old hive may be left in its 

 place under the new one until some cool 

 morning in October, when it can be removed 



=|Q ^05= 



ANOTHER BULLETIN, No. 431, on sac- 

 brood, by G. F. White, Bacteriologist in 



the United 



SAC BROOD 



SOME LATER 



STUDIES 



States Depart- 

 ment of Agricul- 

 ture, is before 

 us. This same 

 author in Bulletin 129, Bureau of Entomol- 

 ogy, made a preliminary report on the same 

 subject, a review of which appeared in 

 Gleanings for March 15, 1913 page 171. 



At that time the author had gone far 

 enough to prove that saebrood was conta- 

 gious but not a serious disease; and he was 

 then of the opinion that the cause was a 

 filterable virus which he extracted from the 

 juices of the dead larvae. The present 

 bulletin confirms his previous opinions, but 

 goes much further into the study of the 

 disease. It contains 50 pages, detailing 

 very minutely his experiments. While it 

 does not set aside any tentative conclusions 

 arrived at in the former one by the same 

 author, yet it does go into the matter so 

 completely and exhaustively that the con- 

 flrsions may now be considered final. 



Saebrood, formerly called pickled brood, 

 dead brood, heated brood, and sometimes 

 confused with both American and European 

 foul brood, especially the latter, has now 

 been determined to be a distinct disease. 

 Up till the time when Dr. White began 

 his work it was generally called " pickled " 

 brood, so named by Dr. Wm. R. Howard, of 

 Texas. But Dr. White's work is so thoro 

 that we must conclude that Dr. Howard 

 was either working with another disease or 

 else made a mistake in his conclusion as to 

 the exciting cause. 



Saebrood after two or three days of seal- 

 ing looks very much like American foul 

 brood, particularly in the matter of per- 

 forated and sunken eappings. American 

 foul brood is normally a disease of the 

 sealed brood, while the European type is 

 normally a disease of the unsealed brood. 

 Saebrood, therefore, is in one i'esi>ect at 

 least similar to American foul brood, and 

 it has certainly been a great many times 

 mistaken for that disease. The appear- 

 ance of the dead larvaa themselves is more 

 like that of European foul brood in that 

 the skin or covering to the larva is neAcr 

 broken. European foul brood attacks the 



larva mainly before it uncurls. Saebrood 

 .attacks its victim after it has sitretch- 

 ed out on the bottom of the cell walls, and 

 a day or two after it is sealed, or just about 

 the time when it begins to spin its cocoon. 

 It does not have the characteristic odor of 

 American foul brood, nor yet does it have 

 the pickled smell mentioned by Dr. Howard. 



The general description of saebrood in 

 this bulletin is so minute and accurate that 

 no one need make any mistake between the 

 three forms of the brood diseases. Cer- 

 tainly a foul-brood inspector who would 

 read this bulletin carefully, and who is 

 familiar with the other forms of American 

 and European foul brood, would be able to 

 make a pretty acurate diagnosis. We there- 

 fore consider that this bulletin will be un- 

 usually valuable, because it will enable the 

 expert beekeeper and the inspector to de- 

 termine whether he has one of the diseases 

 which are dangerous and destructive, or 

 whether he has a mild disease that will 

 disappear of itself, probably, within a 

 month. 



Up to the time this bulletin was published, 

 the average foul-brood inspector could not 

 be entirely sure whether he had a case of 

 dead brood or American or European until 

 he could have a bacteriological determina- 

 tion from Washington ; and while as before 

 he should submit all samples to the Govern- 

 ment, as he has elone heretofore, h? Avill 

 now with this latest bulletin before him be 

 able to come to a pretty definite conclusion 

 as to whether is is saebrood or not. 



The bulletin contains some very fine draw- 

 ings, greatljf enlarged, showing the normal 

 and t!ie di,>oased specimens of larvae in 

 various stages of their development. The 

 drawings alone will give one a pretty ac- 

 curate idea of the external symptoms. 



As to the exciting cause. Dr. White has 

 pi'oven out his former belief that it is due 

 to a filterable virus. That this is the cause 

 beyond question he has proven time and 

 lime again by macerating the bodies of the 

 bees of the diseased specimens, and in- 

 troducing the virus into a syrup fed to 

 liealthy colonies. With this he could make 

 a case of saebrood at any time, and about 

 as bad as 0119 could wish to see. 



Very fortunately, saebrood will disap- 

 pear of itself within a month. The virus 

 is easily killed by heating it to a temjiera- 

 lure of 133 F. in water oi' 158 in honey. It 

 is easily destroyed by the direct rays of the 

 sun, but it seems to h'c peculiai'ly resistant 

 to drugs. 



The proI)a))iIities aie that the disease is 

 not transmissible thru honey, or at least 

 after it has been off the hive for a month. 



