PINE DISEASES 281 



half mile from the pines will probably control this rust. If 

 this distance is not possible, a separation of five hundred feet 

 or more will be partially beneficial. 



In forested areas where wild currants and gooseberries are 

 common, the further growing of white pine may have to be 

 abandoned. The elimination of the bushes over extensive 

 areas will probably never prove as profitable as planting or 

 encouraging natural reproduction of some other species of 

 tree suited to the conditions. Where currants and gooseberries 

 are not very abundant and the experiment of eliminating them 

 is thought practicable, results may be obtained if the work is 

 vigorously prosecuted year after year. The total cost and 

 the possibilities of failure must influence the planning of this 

 kind of control when timber values alone are to be considered. 



Refeebnces 



Spaulding, P. The blister rust of white pine. U. S. Dept. Agr. 



Bur. PI. Ind. Bui. 206: 1-88, pis. 1-2, figs. 1-5. 1911. (Bibli- 

 ography given.) 

 Spaulding, P. The white-pine blister rust. U. S. Dept. Agr. Farmers' 



Bui. 742 : 1-15, pi. 1, figs. 1-5. 1916. 

 Spaulding, P. New facts concerning the white-pine blister rust. 



U. S. Dept. Agr. Bui. 116: 1-8. 1914. 

 Spaulding, P. Foresters have a vital interest in the white-pine 



blister rust. Proc. Soc. Am. For. 11 : 40-47. 1916. 

 Atwood, G. G. Emergency bulletin on the blister rust of pines and 



the European currant rust. New York Dept. Agr. Hort. Bui. 



2 : 1-15, pis. 1-2. 1909. 

 Paul, B. H. The pine blister. New York Conservation Com. Bui. 



15 : 1-18, figs. 1-8, map. 1. 1916. 



Sweet-fern Rust ' 



Caused by Cronartium comptonice Arthur 



This rust disease occurs on two- and three-needle pines in 

 eastern United States and is commonly known as blister-rust. 

 It is found on the native pitch,, scrub, loblolly, western yellow. 



