dividual tree which it infects and it does not spread directly from 

 one pine tree to another. 



The spores scatter in the early spring months and take lodgment 

 on Ribes (currants and gooseberries). In the month of Septem- 

 ber an orange red rust appears on the under side of the leaves of 

 the Ribes. The spores of this fungus then spread to pine trees 

 where they develop in eighteen months as the blister rust of the 

 pine. The fungus form found on Ribes (Cronartium ribicola) 

 was first described fiftv vears ago and named by Dietrich. The 

 form of fungus found on pine trees was first described and named 

 by Klebahn in 1887 as a distinct species and by him named Peri- 

 dermium strobi. Subsequently, through inoculation experiments, 

 it was conclusively proven that Cronartium ribicola on the cur- 

 rant and Peridermium strobi on the pine are not separate species 

 but only different stages of one and the same fungus. With this 

 knowledge it is self evident that, as the disease cannot spread from 

 one pine tree to another and can only be spread from the pine to 

 the currant and from the currant to the pine, the disease can be 

 suppressed if not entirely eradicated by burning 'all the infected 

 pines and all the Ribes growing in proximity. If, therefore, we 

 have suspected disease in valuable pines it is b^st to destroy the 

 less valuable Ribes before they become diseased or show the fungi 

 on their foliage. This procedure is specially urged where the pine 

 plantings are important and where the Ribes are growing wild 

 and are actually worthless. 



Once before — in 1906 — this disease appeared in New York 

 State. It was found by Prof. F. C. Stewart upon the grounds of 

 the New York State Experiment Station at Geneva and prompt 

 and radical treatment was resorted to, which is believed to have 

 completely eradicated the disease. The report upon this outbreak 

 and procedure was issued as Technical Bulletin No. 2 of the New 

 York Agricultural Experiment Station, and owing to the fact that 

 the edition is exhausted a large part of this bulletin is reprinted 

 as an appendix to this circular. 



Blister Rust of White Pine. 

 Prof. Stewart has given careful attention to the present appear- 

 ance of the disease and the following statement was prepared by 

 him : 



" Blister rust is a fungus disease affecting the trunks and 



4 



