28 BOARD OF AGRICULTURE. [Pub. Doc. 



mune. I have seen two trees, one a Russian, the other an 

 American variety, with branches intermingled. In August 

 every leaf on the American was brown with rust, and the tree 

 was annually stripped of its foliage in August until the adja- 

 cent red cedar which harbored the rust fungus was removed. 

 In striking contrast was the Russian variety, upon which 

 careful search failed to reveal a single rusty leaf. There is, 

 therefore, a remarkable difference in disease-resistance be- 

 tween the various varieties of apples. 



But what attention has as yet been given to this ? Who 

 in this country is well informed as to the relative disease 

 resistance of even our standard varieties, to say nothing of 

 the newer ones that are being introduced ? We have recently 

 been searching pomological literature and corresponding with 

 experiment station workers and other experts over the coun- 

 try, and are surprised to lind that no systematic attempt has 

 as }'et been made even to collect and compare the results of 

 chance individual observation, much less to make more exact 

 and systematic observations, experiments and comparisons. 

 The possibilities of actually improving varieties as to disease 

 resistance by systematic breeding and selection are still more 

 remote, owing, of course, to the time element in ap})le im- 

 provement. Yet both of these matters are of most funda- 

 mental importance, as related to the practical operations of 

 apple culture. 



Let us now make similar inquiries as to the relation of the 

 history and development of the potato to its diseases, that 

 the results may be compared with the conclusions already 

 reached for the apple. The aim will be at the same time to 

 examine the Ijearing of such considerations upon certain 

 questions of potato culture and disease control. When at 

 the outset the diseases of these two plants were listed and 

 classified as to causes, a remarkable likeness was apparent, 

 amounting almost to a parallelism. As we proceed now to 

 this later and as I believe more practically helpful method of 

 consideration, the results will be different. I wish to pre- 

 pare you by a sunnnary in advance, that you may see how 

 striking this difference is, and may the more readily follow 

 the details of the discussion, — details Avhich will reveal no 



