PREFACE 



It is a noteworthy fact that there has been available to student 

 and reader no general text or reference book of American origin 

 upon fungous diseases of plants. Nevertheless, for thirty years or 

 more there has been active investigation in this field, and during 

 much of this time instruction in plant pathology has been an 

 important part of biological teaching in all colleges where plant 

 industry or country-life interests have been adequately represented. 

 In the agricultural colleges the teaching of general mycology has 

 been important, and that of plant pathology is now essential. The 

 presentation should be fundamental, but it should also bear a close 

 relation to the affairs of life. Plant pathological work has been 

 rapidly developed in all countries characterized by a progressive 

 agriculture, and for European conditions the student experiences 

 no great lack of reference works. 



Through the agricultural experiment stations and through the 

 extension work in various states a vast amount of information with 

 respect to plant diseases has been published and otherwise dissemi- 

 nated, so that to every intelligent plant producer the opportunity 

 has been extended of becoming more familiar with the crop rela- 

 tions of destructive parasitic fungi. The student and the progres- 

 sive grower require something further, and it has therefore seemed 

 none too early to put in book form a comprehensive discussion of 

 the chief fungous diseases of cultivated and familiar plants. It is 

 not intended that this book shall be an introduction to systematic 

 mycology; yet the arrangement of the material in taxonomic se- 

 quence with respect to the fungi largely eliminates the necessity 

 of any mycological preparation as a prerequisite. 



As far as practicable, in the discussion of each disease, three 

 important considerations have been kept in view : (i) to describe 

 the pathological effects and other relations of host and parasite ; 



