XXX Introduction 



For this reason, too, much space has been given to a 

 consideration of the healthy hosts and of the soil, the 

 mother of all vegetation. 



For the sake of convenience, the crops here con- 

 sidered have been taken up in the natural order of 

 families to which they belong. The families have 

 then been arranged in alphabetical order, and the 

 crops in each family taken up alphabetically by their 

 popular names. On the other hand, the diseases 

 have been arranged according to their causes, classi- 

 fied according to the system generally accepted by 

 students ia mycology. 



The present work is intended as a guide to the 

 trucker and gardener, and to the student in Plant 

 Pathology. It is the result of several years of re- 

 search in truck crop diseases. Where information 

 has been drawn from other sources full references 

 have been given, so far as possible from the latest 

 investigations. The writer has aimed at making 

 this work as broad and as generally useful as possible 

 rather than confining it to local interest. 



Because of the great economic import^ice of the 

 subject of truck crop diseases, it is felt that the pres- 

 ent work fills a timely want and needs no apology. 

 We cannot expect a general test-book on Plant Path- 

 ology to go into lengthy treatment of all plant dis- 

 eases, and even less so with those of the trucking 

 crops. The subject in itself is top important and too 

 broad to be dealt with adequately in a few pages. 

 The time wiU undoubtedly come when the diseases 

 of every important "crop will be treated separately in 



