*"*T'' M T°WIWrnMlTIBTI 
UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 780 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
June 12, 1919 
NOSEMA-DISEASE 
By 
G. F. WHITE, Specialist in Insect Diseases 
CONTENTS 
Introduction 1 
Name of Disease ........ 3 
Digestive Tract of Adult Bees .... ^4 
Cause of Nosoma- Disease ..... 7 
A Three- Year Study of Nosema Infec- 
tion in an Apiary 13 
Symptoms of Nosema- Disease .... 21 
Methods Employed in Experimental 
Siudies . 22 
Effect of Nosema Infection 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 
Resistance of Nosema apis to Putrefaction 35 
Resistance of Nosema apis to Direct 
Sunlight 37 
Period Nosema apis Remains Virulent . 39 
Infectiousness of Brood-Combs from 
Nosema-Infected Colonies . . . .43 
Resistance 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 .... 53 
Summary and Conclusions ..... 56 
Literature Cited . 58 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1919 
