UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 809 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



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



AMERICAN FOULBROOD 



By 



G. F. WHITE 



Specialist iu Insect Diseases 



CONTENTS 



Page 



Introduction 1 



Name of the Disease 2 



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



Symptoms 5 



Etiology . 11 



Technique 17 



Thermal Death Point of American Foulbrood Spores . . ... 22 



Resistance of American Foulbrood Spores to Drying 29 



Resistance of American Foulbrood Spares 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 45 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1920 



