82 Bulletin 186. 



we found it on violets at Floral Park. Tlie plants were ia small 



pots. Some of them had stem-rot, while on others only the bases 



of the petioles were rotten. The rotten parts frequently contained 



RMzoctonia. 



Thus it appears that RTiizoctonia occurs not infrequently on 



violets, but whether as a parasite or only as a saprophyte can not 



now be stated.* 



Other Hosts. 



In addition to the occurrence of Rhizoctonia as an apparent 

 cause of diseases of the host plants already mentioned, there are 

 several other plants upon which we have occasionally found this 

 fungus. For the sake of brevity, we will condense the observations 

 upon these, and bring them together under a single heading, defer- 

 ring their more extended discussion until further observations and 

 studies have been made upon them. 



Rhizoctonia has been found on tlie roots and trunk of a dead 

 cherry tree from Wright's Corners ; as a damping-oii disease of 

 white pine and cucumber seedlings ; on damped-off cuttings of 

 begonia, coleus, verbena, hydrangea, hardy candytuft, and mam- 

 moth sage at Floral Park, N. Y. ; on mature plants of phlox and 

 pyrethrum at Floral Park ; and on young plants of snap dragon at 

 Geneva. Mr. Rolfs has observed it on the raspberry, lamb's quar- 

 ters {Chenopodiiiin alhurn)^ tumble weed {Amarantus alhus), pig- 

 weed (A^narantus retrojlexus), and on decaying squash stems at 



Geneva. 



Parasitism of the Fungus. 



In many cases Rhizoctonia is truly parasitic, and there can be no 

 question about its being the cause of the diseases with which it is 

 associated. The diseases of beet, carnation, lettuce, and some others 

 with which we have experimented may be readily induced by 

 merely placing in contact with the plant pure cultures of the 

 fungus; and in time infection will result, provided there is sufficient 

 moisture. Infection results more readily with the carnation by 

 direct insertion of bits of the fungus into the j)lant. In other cases 



* Violet stem-rot is a complex disease not well imderstood. The fungus 

 TJiielavia hasic' la Zopf is generally accepted as being the cause of it. See Thax- 

 ter, R., Fifteenth Ann. Rep. Conn Agr. Exp. Sta. (1891): 166-167. 



