UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 957 



Contribntion 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 OFFICB 



1922 



