THE PRESENT STATUS OF THE WHITE PINE BLISTER 



RUST CONTROL IN MONTANA 



1918 



By George A. Root 



Field Assistant, White Pine Blister Rust Control, Bureau of Plant Industry, U. S. 

 Department of Agriculture. 



The Laboratory of Forest Pathology of the Bureau of Plant 

 Industry, located in Missoula, Montana, in charge of Dr. James R. 

 Weir, has taken precautions during the past two years to prevent the 

 introduction of the white pine blister rust, a very serious disease attack- 

 ing all species of white pine. The immense stands of white pine in the 

 West are in danger of attack by this disease, if ever the infection is 

 carried thus far. 



The western states, especially those of the northwest sections, 

 contain an immense supply of the finest timber marketable. The 

 northwestern part of iMontana is included in this western white pine 

 belt, and therefore, the subject of the blister rust work is of vital 

 importance to this state. The destructive character of this disease 

 and the economic loss which it threatens in some of the New England 

 states and New York, should bring the people of this section to a 

 realization of its seriousness and the importance of keeping it from 

 gaining a foothold here. 



This disease was imported on white pine nursery stock from 

 Europe and first appeared in Geneva, New York in 1906. Warnings 

 had been repeatedly sent out against the importation of white pine 

 stock from Europe, but in spite of this many subsequent importations 

 were made. The discovery of this disease at various times between 

 1906 and 1912, finally led to Federal action, which barred all such 

 importations. 



The white pine blister rust is not an insect, as many erroneously 

 suppase, but a plant disease and attacks all five-leaf pines, especially 

 the eastern white pine. This disease is similar to the wheat rust, 

 in that it requires another host plant to complete its life cycle. 

 Instead of the alternate host plant being the common barberry, as in 

 the case of the wheat, it requires some members of the genera Ribes 

 and Grossularia (currants and gooseberries). (See Fig. 1). A 



