SMITHSONIAN INSTITUTION LIBRARIES 



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breeding races and varieties of the species which would be permanently 

 immune. 



Breeding experiments have been begun in cooperation with the Bureau 

 of Plant Industry and the Forest Service, but it will require several 

 years to get definite results. In the meantime, however, it is important 

 that seed and cuttings for commercial planting should be selected as 

 far as possible from trees which show least damage from the borer and 

 are otherwise vigorous and healthy. From a well-established principle 

 in the heredity of plants and animals this practice of propagating from 

 the best examples must certainly yield better results than would follow 

 a disregard of the character of the trees from which seed or root propa- 

 gations are made. 



Approved : 



James Wilson, 



Secretary of Agriculture. 



Washington, D. C, February 1, 1907. 



O 



