INSTITUTE PAPERS. 



POTATO DISEASES AND THEIR REMEDIES. 



By Prof. L. R. Jones, University of Vermont. 



There is nothing more important to the highest success than a 

 sense of confidence in the mastery of one's business. This is 

 especially true of the farmer. In certain phases of crop produc- 

 tion no other thing has so diminished this confidence as the 

 baffling experiences often had with plant diseases. Most men 

 soon learn to handle the normal plant under good conditions, 

 but when the dreaded blight or rust appears they lose their grip. 



Formerly it was commonly held that such diseases were divine 

 visitations and that any attempt to check them would be an inter- 

 ference with the workings of Providence. More recently we 

 have learned that for most of these diseases there is a specific 

 parasite — an insect or a fungus which causes it. Realizing this, 

 our confidence in the efficacy of specific remedies, of insecti- 

 cides and fungicides, has rapidly increased. The results of 

 spraying in late years have indeed been most encouraging, and 

 it is an important part of my message to stimulate more and 

 better spraying. But I first wish to emphasize the point that 

 spraying alone is not everything — or even the most important 

 thing — in growing potatoes or any other crop. Each year 

 brings the fuller realization that the first thing is to learn more 

 fully how the normal plant feeds, develops and reproduces itself, 

 that by intelligently aiding it in these processes we may secure its 

 fullest possible vitality. Having done this we may finally gain 

 great profit by intelligently spraying to preserve that health and 

 vigor. The point I would emphasize at the outset is that spray- 

 ing does not make sick plants healthy, but instead it keeps 

 healthy plants from becoming sick. 



The Commissioner of Agriculture has asked me to discuss the 

 diseases of the potato and their control, and I especially wish to 



