H3 
UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 957 
Contribution from the Bureau of Plant Industry 
WM . A. TAYLOR, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
February 6, 1922 
INVESTIGATIONS OF THE WHITE-PINE 
BLISTER RUST 
By 
PERLEY SPAULDING, Pathologist, 
Office of Investigations in Forest Pathology 
CONTENTS 
Page 
Scope of the Investigations ....... 1 
Origin and Distribution of Cronartium 
ribicola 3 
Hosts of Cronartium ribicola 11 
Life History of Cronartium ribicola . . 24 
. Page 
Overwintering of Cronartium ribicola . . 68 
Important Dates in the Life History of 
Cronartium ribicola 72 
Control of the White-Pine Blister Rust . 73 
Literature Cited 90 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1922 
