Minnesota Plant Diseases. 203 



necessarily differ and the judgment of the operator is always im- 

 portant. The value of that judgment is measured only by his 

 knowledge. The more he knows of the causes and action of 

 the disease the more intelligently and the more successfully will 

 he be able to combat it. The various remedial measures solu- 

 tions, formulas, sprays and spray machinery are all important, 

 indispensable in fact but they are not the ultimate object; 

 they are the means by which relief is secured and the observant 

 operator who knows what he is doing and why he is doing it 

 has many more chances of success than he who is following 

 book rule. I shall deem myself eminently successful in this 

 work if I shall be able to contribute to such a spread of useful 

 knowledge as shall fortify the efforts of all plant growers in the 

 state. The solutions of these problems lie largely I might al- 

 most say entirely with the men who are the operators. The ob- 

 ject of this work is to help him to an understanding which will 

 give reason and intelligence to his efforts. It is obvious, of 

 course, that an objection will immediately be raised, viz. : the 

 farmer cannot hope to master all of the details of the life-stories 

 of disease-causing organisms his time is occupied with the 

 practical problems and operations of plant growing. And this 

 objection has much of truth in it. Nevertheless, success in all 

 lines is becoming more a matter of knowledge. What the farm- 

 er can do and must do is to know more about the plants with 

 which he has to deal and these include not only his wheat and 

 apples but the enemies of these plants as well. He must pick 

 out from the results of those who have worked out and de- 

 scribed the details of disease such facts as are of use to him and 

 apply those results. 



Successful agriculture is no longer the simple method it was 

 of old, i. e., the planting of the seeds and the trusting to provi- 

 dence for favorable conditions of growth and produce. It is the 

 scientific control of those conditions. The farmer alone stands 

 helpless. The plant pathologist is an absolute necessity in the 

 agriculture of today. His results must increase the efficiency 

 of the farmers' efforts and they will if they are intelligently ap- 

 plied. In this specialization the plant pathologist is by no 

 means independent. He is just as dependent upon the coopera- 

 tion of the farmer as the latter is upon him. In other words, 



