THE WHITE-PINE BLISTER RUST 



97 



THE BLISTER RUST DISEASE OF WHITE PINE. 



By Dr. PEREEY SPAULDING 



PATHOLOGIST O. S. DEPARTMENT OF AGRICULTURE 

 [The White-pine Blister Rust which has been discovered in various sections of the New England States, New York State and 

 in Ontario, Canada, threatens to do most serious damage to white pine and western sugar pine in the United States and Canada. 

 There apparently is no way of overcoming it except to prevent shipments of pine seedlings from the infected sections, and by 

 destroying infected pine trees, and currant and gooseberry bushes. This article and illustrations tell how to ascertain the presence 

 of the disease, and what to do when found, and also sounds a warning against mistaking another for it. Editor ] 



A HoenlCoBllUmare 



THE WHITE-PINE BLISTER RUST 

 Figure "A" shows a young white pine with open blisters and swollen bark. 

 Figure "B" shows a leaf of flowering currant bearing the early currant stage. 

 Figure "C" is a part of the same leaf much magnified and showing four of the spore masses. 

 Figure "D" shows a black currant leaf bearing the late filamentous stage, this being the stage in 

 which it is transmitted to the pine trees. 



"A," "B" and "I)" natural size. 



The White-pine Blister Rust is such a serious dis- 

 ease, and conditions are so favorable for its ultimate 

 spread throughout the area inhabited by the white piue 

 in this country, that the danger is very grave. 



It is also known to attack the sugar pine of the 

 Pacific Coast region; the western white pine of the 

 northern Rocky Mountain region and the lumber pine 

 of the Rocky Mountain region. 



of 



The U. S. Forest Service estimates the value 

 these pines at $411,000,000 divided as follows : 



White pine New England States, $75,000,000; 

 Lake States, $96,000,000; Western States, $60,000,000; 

 on National Forests, $30,000,000. 



Western sugar pine Western States, $105,000,000; 

 on National Forests, $45,000,000. 



