Canadian Foicsfri} Journal, June, 1918 



1743 



The Fight to Save Our White Pine 



By Prok. J. II. Faill, Ph.D., Univkrsity of Toronto. 



Northern Ontario and Western Canada Must be 

 Guarded Against Deadly Menace of Blister Rust. 



The terrific destruction wrought by 

 introduced fungi and insects has 

 been demonstrated too often to allow 

 us to supinely take a chance with 

 White Pine Blister Rust. It has been 

 recently estimated that the United 

 States alone suffers losses of at least 

 $500,000,000 annually from imported 

 pests. Two or three examples will 

 suffice. The potato blight was 

 brought into Ireland in the middle 

 forties; two years of its ravages 

 served to cut the population of Ire- 

 land into two by deaths from famine 

 and by emigration; its effects even 

 reached America, and the Irish poli- 

 tical domination in New York and 

 other places along the Atlantic sea- 

 board today is to be traced back to 

 the immigrations of that period. 

 The American grape mildew gained a 

 foothold in France about 1850. The 

 result was disastrous, the yield being 

 reduced to one-tenth or one-twen- 

 tieth of the normal, ruining growers, 

 causing migration, and necessitating 

 a radical change in cultural methods. 

 The latest instance is that of the 

 chestnut blight, a disease introduced 

 from central China on stock of the 

 Chinese chestnut; starting from New 

 York city in 1904, it has swept re- 

 lentlessly to the northern limits of 

 the chestnut forests, to the west as 

 far as western Pennsylvania, and 

 south into the Virginias and Ten- 

 nessee, over wide stretches destroy- 

 ing 100 per cent, of the chestnut of 

 all ages, resulting in a loss that two 

 or three years ago was variously 

 estimated up to $100,000,000; the 

 calculations of foresters for refores- 

 tation throughout the chestnut zone 

 have been completely upset; the 

 value of the chestnut as a basic 

 forest tree has vanished. The fungus 

 that causes the blight we now know 

 occurred only in China on Chinese 



chestnut, which is so resistant that 

 comparatively little damage results. 

 Up to 1904 the fungus was not known 

 to science and was apparently re- 

 stricted in its destribution to China. 

 It is a striking example of the in- 

 creased virulence exhibited by many 

 parasites when transferred to a new 

 species or variety of host. 



Blocking New Diseases 



Passing around the circle we find 

 our optimists linked with the equally 

 dangerous fatalistic pessimists, who, 

 too, would pursue a laissez faire 

 policy. They argue that wherever 

 there is commercial intercourse the 

 maladies will follow the traders' flag, 

 and that in spite of our best efforts, in 

 time plant pests of every kind will 

 spread to all parts of the civilized 

 world, limited only by the existence 

 of unfavorable natural conditions. 

 They are wrong, for, just as many 

 diseases of man have been prevented 

 from gaining a foothold in Canada 

 and the United States, such as bu- 

 bonic plague and leprosy, so too, 

 there are hundreds of plant diseases, 

 like European potato canker and the 

 root knot of alfalfa that have not been 

 allowed to establish themselves on 

 the American mainland. Speaking 

 for the Department of Agriculture of 

 the United States, one of their leading 

 plant pathologists remarks: "The 

 securing of these diverse species and 

 varieties of plants from all quarters 

 of the world, however, ^s always 

 accompanied by the danger of intro- 

 ducing foreign diseases of these plants 

 along with the plants themselves. A 

 special inspection is maintained for 

 the purpose of preventing the intro- 

 duction of such diseases, and it is 

 not overstating the truth to say that 

 dozens of dangerous new diseases 

 are intercepted every year." 



