UNIVERSITY OF ILLINOIS 



Agricultural Experiment Station 



URBANA, ILLINOIS, JUNE, 1916 



BULLETIN No. 189 ABSTRACT 



PARASITIC RHIZOCTONIAS IN AMERICA' 



BY GEORGE L. PELTIER, ASSOCIATE IN FLORICULTURAL PATHOLOGY 



INTRODUCTION 



One of the most serious and troublesome diseases which must be 

 contended with by carnation growers in this country is the so-called 

 "stem rot" due to the fungus Rhizoctonia. In July, 1912, a study of 

 this disease was undertaken by the writer, together with a thoro in- 

 vestigation of those diseases of vegetable, field, and floricultural crops 

 which are caused by Rhizoctonia, the primary object being to deter- 

 mine whether infection is brought about by one or by more than one 

 race or species of this fungus. 



DISTRIBUTION OF RHIZOCTONIA 



The fact that 165 species of plants are reported as being more or 

 less susceptible to RJiizoctonia Solani Kiihn (Corticium vagum B. & C.) 

 in the United States indicates the wide distribution of the fungus in 

 this country. The writer himself has observed this fungus on seventy- 

 five species, sixty-five of which were greenhouse plants. It is obvious 

 that as long as investigations are continued the list of plants re- 

 ported as susceptible cannot be regarded as complete or final. Plants 

 belonging to the families AmarantJiacece, Caryophyllacece Cruciferce, 

 Leguminosce, Solanacece, and Composite are especially susceptible. 

 Under favorable conditions the fungus can attack plants in these 

 families at any stage, when grown either in the field or in the 

 greenhouse. About fifty important families of flowering plants are 

 represented, several gymnosperms, and Equisetum, one of the Pteri- 

 dophytes. The list includes a number of monocotyledons, which for- 

 merly were reported as being non-susceptible to Rhizoctonia. Among 

 the dicotyledons are many annuals and perennials, including herbs 



'The complete edition of Bulletin 189, consisting of 112 pages, will be sent 

 upon request. Address Director, Illinois Agricultural Experiment Station, Urbana, 



