282 



SCIENCE 



[N. S. Vol. XL VII. No. 1212 



Plant pathology has had a magnificent 

 development during the last 20 years, and 

 yet only a beginning has been made. As 

 yet there are few if any plant diseases 

 which we can say have been conquered and 

 practically eliminated from consideration 

 as the cause of any considerable economic 

 losses. There is no record that any plant 

 disease, after having once thoroughly es- 

 tablished itself over a considerable terri- 

 tory, has ever been eradicated. Nor is there 

 any plant disease which is to-day being ef- 

 fectively controlled in practise except in 

 limited areas, no matter how simple or how 

 effective the control measures are. Reme- 

 dial measures are known for many diseases, 

 and there are many whose complete control 

 is easily possible, but the public has never 

 been aroused to the necessity of thorough 

 and persistent application of the remedies. 

 Pathologists have not completed their 

 work. We need more propaganda to in- 

 struct and to arouse sentiment in favor of 

 disease control. We need public control of 

 plant sanitation, as we have a public health 

 service for human beings. We need laws 

 requiring treatment of grain for smut as 

 we now have laws requiring smallpox vac- 

 cination. At this time when the world is 

 hungry, the producer of food has no more 

 right to jeopardize or to neglect the health 

 of his crop than you or I to endanger the 

 public health. And the plant pathologist, 

 as the guardian of the health of food crops, 

 should rank in importance with the medical 

 practitioner and the public health officer. 

 We have come to the time when plant pa- 

 thology should be carefully reorganized as 

 a public service and when pathologists 

 should scrutinize all phases of their work 

 and see to it that no important part is neg- 

 lected. The need for this action has been 

 increased by the world war but it would 

 have become necessary soon had the world 

 remained at peace. 



In glancing over the history of plant pa- 

 thology we see that the first phase of the 

 subject to develop was research work on the 

 diseases — study of the life histories of the 

 causal organisms, and of their relations to 

 and effects upon the host plants. Perhaps 

 control measures were also worked out, but 

 with the publication of his paper the in- 

 vestigator dropped the subject without ma- 

 king sure that the results of his investiga- 

 tion were carried to the grower. Much 

 valuable work of this character has been 

 severely criticized as being impractical, 

 some critics even now going so far as to 

 urge that research work be suspended en- 

 tirely for a time and attention concentrated 

 on the practical application of present 

 knowledge. 



More recently there has developed a sec- 

 ond phase of phytopathological work, i. e., 

 extension work or the actual carrying of the 

 results of investigation to the farmer, and 

 the practical demonstration to him of con- 

 trol methods, thus bridging the gap between 

 investigator and grower. Great progress 

 has already been made in this field and 

 plans are now maturing for still further de- 

 velopment. This is a line of work of the 

 greatest importance, which should be spe- 

 cially pushed at this time in order that the 

 ravages of disease may be effectively 

 checked in those eases where adequate con- 

 trol measures are already known. 



There remains a third phase of patholog- 

 ical work, which we may call the intelli- 

 gence service, which is fundamental in im- 

 portance and is contributory to the success 

 of both research and extension work. A 

 well-organized intelligence service is a nec- 

 essary adjunct to every large enterprise. 

 Armies have their scouts and spies, their 

 raiding parties on land and aeroplanes in 

 the air, to keep the commanders informed of 

 the movements and plans of the enemy. 

 Great business houses have their domestic 



