WHITE-PINE BI.rSTRR RUST. 5 



found much earliei-, and more of it would have been found since 

 then. Fischer (40) found the disease in 1915 spreading into western 

 and northern Switzerland from without. 



It is generally supposed that Pinus cemhra (26, 70, 93, 97, 98, 123) 

 is the original pine host of this fungus. Figure 1 shows the distri- 

 bution of P. cemhra and its variety pumila in Europe and Asia. 

 Oronartium ribicola is reported from Asia as follows: In 1879, from 



¥%J ft-;i.i.:^ex«^ f ...^r "^ ^ •••7 



rl^i^^l -. -^:-\ '/ ■ '^^ 



^^W^--^|. i \r x;^ -^ 



Fig. 2.— Outline map of the United States, showing the known distribution of Cronartium ribicola and 

 C. occidcntale in North America to January 1, 1920. Localities for Cronartium occidentale are shown by- 

 black squares in the Pacific coast and Roclq^ Mountian regions, the easternmost point being in western 

 Kansas. This is where it was found in 1892, but it has not been seen there since. Localities for C. ribicola 

 are indicated by double cross hatching and black dots, nearly all bemg north of the Potomac and Ohio 

 Rivers and east of the Mississippi liiver. Four points in southwestern ilinnesota, eastern South Dakota, 

 and northern Iowa were found to be due to diseased nursery stock which was shipped in. It is believed 

 that the disease now has been eradicated in these outer western localities. The natural distribution of 

 the eastern white pine is shown in the large cross-hatched area mostly oast of the Mississippi River. The 

 cross-liatchcd areas shown on the western half of the map indicate the known distribution of the western 

 white pines. The pinon pines range as far north as southern Idaho but at altitudes different from those 

 of the wliite pines. Cronartium ribicola is limited to the eastern white-pine area and was not known in 

 North .\merica until 1906. In most places where now found it has been traced to diseased imported 

 white-pine stock. Cronartium occidentale is limited to that part of the western white-pine area in which 

 piilon pines arc native, where it appears also to be native. The two fungi are separated by a strip of 

 prairie country about 500 miles wide. Distribution of the pines furnished by the Forest Service, United 

 States Department of Agriculture. Distribution of Cronartium occidentale furnished by Messrs. Bethel 

 and Posey, of the OfTices of Investigations in Forest Pathology and of Blister-Rust Control, respectively. 



Bolschaja Inja River (131, 161); also from Tomsk and Minusinsk, 

 Siberia (131). Quite recently it has been reported from Sakhalin 

 Island and from Sapporo, Japan (156). Tulasne (175) in 1854 re- 

 ported a Cronartium on Ribes, probably in India. Clinton has 

 announced (13) the finding of Cronartium rihicola on dried herbarium 

 specimens of Ribes collected by Wilson in the western part of the 

 Province of Ilupeh, China, in 1900. 



