UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 809 



Contribatlon from the Bureau of Entoniolo2)' 

 L. O. HOWARD, Chief 



Washington, D. C. PROFESSIONAL PAPER March 10, 1920 



AMERICAN FOULBROOD 



By 



G. F. WHITE 

 Specialist in Insect Diseases 



CONTENTS 



Page 



Introduction 1 



Name of the Disease 2 



Healthy Brood at the Age at Which It Dies of American Fonlbrood . . 3 



Symptoms 6 



Etiology 11 



Technique 17 



Thermal Death Point of American Foulbrood Spores 22 



Resistance of American Foulbrood Spores to Drying 29 



Resistance of Americ&n Foulbrood Spores to Direct Sunlight ... 29 



Resistance of American Foulbrood Spores to Fermentation .... 31 



Resistance of American Foulbrood Spores to Chemical Disinfectants . 31 



Effect of Drugs on American Foulbrood 32 



Modes of Transmission . 34 



Diagnosis ...36 



Prognosis ' 38 



Summary and Conclusions 39 



Literature Cited 42 



Explanation of Plates 4S 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1920 



