THE STERILE FUNGUS RHIZOCTONIA AS A 

 CAUSE OF PLANT DISEASES IN AMERICA. 



Being a Preliminary Keport upon the Occurrence of Dis- 

 eases OF Plants in America Caused by Different Forms 

 OF THE Sterile Fungus Phizoctonia. 



By B. M. DuGGAR. Ciyptogamic Botanist, Cornell University Agl. Exp, Sta. , 

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



Introductory. 



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

 drew the writers' attention particnlarlj to the fungus Rldzoctonia 

 as a cause of various plant diseases in this country. It needed no 

 extended search to ascertain that this fungus is much more com- 

 monly associated with diseases of certain greenhouse and iield plants 

 than our economic literature would suggest. During the three 

 seasons that our attention has been directed to this matter, the 

 occurrence of Wiizoctonia on some entirely new hosts has been 

 observed, and also upon other hosts new^ to America. As a pre- 

 liminary report, it now seems well to bnng the subject to the atten- 

 tion 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 bulletin 

 concei'ns 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 mor- 

 phology and physiology of the forms, as well as general matters of 

 taxoiiomic interest and a discussion of European species. Nothing 

 will at present be said of the limitations or identity of species. 



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