The White Pine Blister Rust. 237 



While Cronartium ribicola discolors the foliage, otherwise it 

 is not considered very destructive to the currant bushes. 



The means of combating this fungus, while very simple, are not 

 always practical or effective. 



The fungus can live for several years in the pine, and may be 

 present for a year in the stems of white pine seedlings before ap- 

 pearing on the surface as a blister. This fact makes the detection 

 of the fungus by means of even a careful inspection or fumiga- 

 tion at the port of entrance of more than doubtful effectiveness. 



All the seedlings affected by the fungus must, of course, be at 

 once pulled up and burned ; all currant bushes in the vicinity of 

 the plantation should be destroyed, which, if effectively done, 

 would starve out the fungus. The most effective way, of course, 

 would be to prohibit any importation of white pine stock from re- 

 gions where the fungus is known to be prevalent. In our present 

 unpreparedness for furnishing planting stock of the desired 

 quality, cheaply and in large quantities, this measure would prove, 

 however, a considerable drawback to the planting movement, 

 which has shown so much vigor within the last few years. The 

 situation demands immediate and careful action, which, without 

 checking the interest in planting in this country, would, at the 

 same time, remove the possibility of introducing and spreading a 

 dangerous enemy of our native white pines. 



