UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 431 



Contribotion from the Borean of Entomoloify 

 L. O. HOWABD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



Febraary 9, 1917 



SACBROOD 



By 



G. F.WHITE 

 Expert, Engaged in the Investigation of Bee Diseases 



CONTENTS 



Page 

 InlitMluclton • • ~« '•-•'v»^« • • • • 1 



Historical Account 2 



Name of the Disease 4 



Appearance of Healthy Brood at the Age 



at Whichit DiesofSacbrood .... 6 



Symptoms of Sacbrood 10 



Cause of Sacbrood 24 



Weakening Effect of Sacbrood Upon a 



Colony 30 



Amount of Tiraa Beqoired to Produce 



the Disease, and the Bapidlty of its 



Increase 31 



Methods Used in Maldng Experimental 



Icoculations 32 



Means for the Destruction of the Virus of 



Sacbrood 34 



Heating Required to Destroy Sacbrood 



Virus When Suspended in Water . . 34 

 Heating Required to Destroy Sacbrood 



Vims When Suspended in Glycerine . 35 

 Heating Required to Destroy Sacbrood 



Vims When Suspended in Honey . . 36 

 Resistance of Sacbrood Vlma to Drying 



ai Room Temperature 37 



Page 

 Besfstance of Sacbrood Virus to XHrect 



Sunlight When Dry 38 



Resistance of Sacbrood Vims to Direct 



Sunlight When Suspended in Water . 39 

 Resistance of Sacbrood Vims to Direct 

 Sunlight When Suspended in Honey . 

 Length of Time that Sacbrood Virus Be> 



mains Virulent in Honey 40 



Besistance of Sacbrood Virus to thePres* 



ence of Fermentative Processes ... 41 

 Besistance of Sacbrood Vims to Fer- 

 mentation in Diluted Honey at Out- 



door Temperature 42 



Besistance of Sacbrood Vims to the Pres- 

 ence of Putrefactive Processes ... 

 Besistance of Sacbrood Vims to Carbolic 



Acid 44 



Modes of Transmission of Sacbrood . . 46 



Diagnosis of Sacbrood 48 



Prognosis 49 



Relation of These Studies to the Treat- 

 ment of Sacbrood . SO 



Summary and Conclnstona ...... 62 



Utatatore Cited 5S 



40 



43 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1917 



