2 BULLETIN 1186, U. S. DEPARTMENT OF AGRICULTURE. 
be effectively protected (10). Control is accomplished by uprooting | 
all wild and cultivated currant and gooseberry plants (Ribes) within 
a distance of 600 to 900 feet of the trees to be protected. ‘The de- 
struction of wild currant and gooseberry bushes can be accomplished 
at a cost sufficiently low to make it practicable and profitable to safe- 
guard the valuable white-pine crop of the Northeastern States. In 
the five years from 1918 to 1922 the cost of removing 19,224,118 
wild currant and gooseberry bushes from 1,504,945 acres of forest 
and pasture land averaged 31.8 cents per acre. Any white-pine stand 
protected in this manner is safe from further rust infection for at 
least 5 to 10 years, and in many cases permanently, depending on 
whether or not local conditions are favorable or unfavorable to the 
growth of wild currant and gooseberry bushes. Several years of 
careful study are required to develop and perfect the cheapest and 
simplest methods of control, since many phases of this work are still 
in the experimental stage. Meanwhile, the control measures that 
have been developed should be generally applied at once to prevent 
further losses from this disease. 
The writer, a forester, observed the blister-rust situation in several 
European countries in 1919 and 1920 and takes this opportunity to 
acquaint others with his observations, which should be of especial 
interest to timberland owners on account of the rapid spread of the 
disease in the Northeastern States and its occurrence in British 
Columbia and Washington. Unless otherwise specified, the state- 
ments are based on the writer’s observations. It would have been 
quite impossible to conduct the work without the assistance and 
advice of scientists, departments of agriculture, and forest officials 
in the countries visited. The writer wishes to express his sincere 
appreciation to those who freely gave their time and efforts, which 
contributed so largely to the progress of this work. 
SCOPE OF THE INVESTIGATIONS. 
The primary purpose of this work was to gather information re- 
garding European methods of dealing with the white-pine blister 
rust which would assist in the control campaign in America. To 
accomplish this purpose, plantations of infected white pine were 
studied, foresters and pathologists interviewed, and data compiled 
as to the actual and financial loss caused by the disease. This work 
was supplemented by visiting the nurseries to observe their sanitary 
conditions, in order that a first-hand opinion might be formed as 
to the justification of the rigid quarantine regulations adopted by the 
United States against imported nursery stock. In addition, all 
available historical and biological data concerning the fungus were 
collected in Norway, Sweden, Denmark, Great Britain, France, and 
Belgium. ‘Typical specimens of ornamental white pine were seen 
very frequently in European parks and arboretums (Pl. I.). Even 
under the most favorable conditions they become prey for the blister 
rust. 
As the writer was in Sweden during the fall of 1919 and winter of 
1919-20, work was begun in that country and extended to cover 
Norway and Denmark. By the middle of July the field was shifted 
to the British Isles, then to France and Belgium, which were com- 
pleted on N ovember 1, 1920. Miscellaneous notes were also gathered 
