340 



BULLETIN No. 189 



[June, 



Salvia. The strain from salvia was isolated from cuttings which were found 

 in the same bench with a number of other cuttings damping off, October, 1912. 



Sedum. A culture of Ehizoctonia from sedum was isolated from diseased 

 plants found in the herbaceous grounds in July, 1913. 



Sugar Cane. A culture of Ehizoctonia isolated from sugar cane was re- 

 ceived from Dr. C. W. Edgerton, November 12, 1912. This culture was obtained 

 in April, 1912. It was fresh and virulent. 



Thistle. A culture of Ehizoctonia from thistle was obtained by Mr. Ander- 

 son from Cornell University in 1911. 



The method of infecting the cuttings, seedlings, and young plants 

 grown in flats and benches, was as follows : Small flats, varying in size 

 with the experiment, were first soaked in a strong solution of formalin 

 for several minutes and then allowed to dry. Steam-sterilized sand 



or soil and a soil culture of Rhi- 

 zoctonia were then mixed to- 

 gether in the flats and watered. 

 After being tamped down, the 

 flats were left standing for two 

 days in order to allow the fun- 

 gus to spread thru the soil. 

 Later, the cuttings, seeds, or 

 plants were put in the flats and 

 placed in a chamber in the green- 

 house where the moisture could 

 be controlled. Bottom heat was 

 furnished. The temperature var- 

 ied somewhat during the experi- 

 ment, but the average was about 

 60 F. When only individual 

 plants in pots or in benches were 

 to be infected, a portion of a cul- 

 ture of Rhizoctonia two weeks 

 old on green-bean plugs was 

 placed in contact with the stem 

 of each plant about one-half 

 inch below the surface of the soil, 

 where it would be protected from 

 light and desiccation. 



In obtaining soil cultures of 

 Rhizoctonia in large quantities. 

 Mason jars with modified covers 

 were found to be very suitable 

 containers. A hole about one 

 inch in diameter was cut in the 

 FIG. 17. SOIL CULTURE OF 

 RHIZOCTONIA 



