UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 780 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



June \2, 1919 



NOSEMA-DISEASE 



By 

 G. F. WHITE, Specialist in Insect Diseases 



CONTENTS 



Page 



Introduction 1 



Name of Disease 3 



Digestive Tract of Adult Bees .... 4 



Cause -of Ncsema- Disease 7 



A Three- Year Study of Nosema Infec- 

 tion in an Apiary ........ 13 



Syrn: ' .'ns of Nosema-Disease .... 21 



Metlio'Js Emp'.oyed in ExperimentaJ 



Studies 22 



Effect of Nosema Infeciion on the Colony 



and on the Apiary 23 



Resistance of Nosema apis to Heating , 29 

 Resistance of Nosema apis to Drying . 31 

 Resistance of Nosema apis to Fermenta- 

 tion 33 



Page 

 35 



Resistance of Nosema apis to Putrefaction 

 Resistance of Nosema apis to Direct 



Sunlight. 37 



Period Nosema apis Remains Virulent . 39 

 Infectiousness of Brood-Combs from 



Nosema-Infected Colonies .... 43 

 Resistamce of Nosema apis to Carbolic 



Acid 44 



Effect of Drugs on Nosema-Disease . .44 

 Modes of Transmission of Nosema-Dis- 

 ease 46 



Diagnosis of .Nosema-Disease .... 48 



Prognosis in Nosema-Disease .... 63 



Simmary and Conclnsions 66 



Literature Cited 68 



WASHmGTON 



I30VERNMENT PRINTINa OFFXCE 



1919 



