UNITEDTSTATES DEPARTMENT OF AGRICULTURE 
Id Cooperation with the 
Washington Agricultural Experiment Station 
DEPARTMENT BULLETIN No. 1239 
Washington, D. C. 
May, 1924 
STUDIES IN THE PHYSIOLOGY AND CONTROL 
OF BUNT, OR STINKING SMUT, OF WHEAT 
By 
HORACE M. WOOLMAN, Field Assistant in Cereal-Disease Investigations, and HARRY B. HUMPHREY 
Pathologist in Charge of Cereal-Disease Investigations, Office of Cereal Investigations 
Bureau of Plant Industry 
CONTENTS 
Physiologic Factors Affecting the Development of Bunt *•• 1 
The Problem of Soil Infestation •*. 2 
Duration of Viability of Bunt Spores in the Soil «... 6 
Physiologic Response of Spores of Tilletia to Temperature 8 
Relation of Soil Moisture to Infection . . . 11 
Morphologic Response to Pathologic Conditions 12 
Relation of Temperature to the Germination of Bunt Spores and Wheat Kernels . 15 
Control of Bunt 18 
Nursery Studies in Seed Treatment • 18 
Relation of Depth of Seeding to Bunt Production 21 
Relation of Rate of Seeding to Bunt Production 23 
Breeding and Selection Studies of Varietal Resistance to Bunt 25 
Summary .............••••••••••••••••27 
Literature Cited 28 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1924 
