THE STERILE FUNGUS RHIZOCTONIA AS A 

 CAUSE OF PLANT DISEASES IN AMERICA. 



Being a Preliminary Report upon the Ocourrencb op Diseases 



OF Plants in America Caused by Different Forms 



OF THE Sterile Fungus Rhizoctonia. 



By B. M. DuGGAR, Cryptogamic Botanist, Cornell University Agl. Exp. 

 Sta. and F. C. Stewart, Botanist, New York Agl. Exp. Sta. 



INTRODUCTION. 



Studies on a beet root-rot and a carnation stem-rot in 1898 

 first drew the writers' attention particularly to the fungus 

 Rhizoctonia as a cause of various plant diseases in this country. 

 It needed no extended search to ascertain that this fungus is 

 much more commonly associated with diseases of certain green- 

 house and field plants than our economic literature would sug- 

 gest. During the three seasons that our attention has been 

 directed to this matter, the occurrence of Eliizoctonia on some 

 entirely new hosts has been observed, and also upon other hosts 

 new to America. As a preliminary report, it now seems well 

 to bring the subject to the attention of American mycologists. 

 Our work is directed towards a monograph including all known 

 species of this fungus; and it is hoped that these notes will 

 enlist the support of other workers, and some contributions of 

 material. 



Besides a brief historical and morphological account, this bul- 

 letin concerns itself merely with the presentation of some notes 

 upon the occurrence and destructiveness of American forms 

 observed by the authors. We reserve for the final paper all 

 details of special morphology and physiology of the forms, as 

 well as general matters of taxonomic interest and a discussion of 



