New York Agricultural Experiment Station. 117 



irregular sclerotia are found attached to the subterranean por- 

 tion of the stem and occasionally to the roots. 



That Rhizoctonia is the cause of this carnation stem-rot has 

 been proven conclusively by inoculation experiments. with puro. 

 cultures repeated many times. Plate IX is from a photograph of 

 a carnation plant killed by artificial inoculation with a pure 

 culture of Rhizoctonia. It presents the symptoms typical of the 

 Rhizoctonia stem-rot disease. 



This stem-rot '^ is one of the most troublesome of the carnation 

 diseases and probably occurs throughout the whole United 

 States wherever the carnation is grown. Frequently entire 

 houses of mature plants are destroyed by it. During the past 

 autumn it appears to have been unusually prevalent. It at- 

 tacks plants of all ages both in the field and in the greenhouse, 

 and is one of the principal causes of the damping off of carna- 

 tion cuttings. In greenhouse benches it spreads slowly through 

 the soil from one plant to another; but according to our experi- 

 ments never through the air, as from one bench to another. Its 

 principal mode of dissemination is by means of affected plants 

 and cuttings. 



ON THE sweet WILLIAM. 



{Dianthus barbatus.) 



Since Rhizoctonia is an active parasite on the carnation, it is 

 to be expected that it attacks the closely related Dianthus bar- 

 batus, and such appears to be actually the case. 



November 5, 1900, we had the privilege of examining a badly 

 diseased plat of about 1,600 plants of Dianthus "barbatus at 

 Queens, Long Island. In the course of the season about 90 per 

 ct. of these plants had died from a sort of stem-rot. Several 

 of the dead plants were not completely dry at the time of our 

 visit, so it was possible to get some^ idea of the nature pf the 

 disease and its cause. The symptoms were strikingly like those 



'There Is a somewhat similar and destructive Fusarium stem-rot of car- 

 natious. See Sturgis, W, C, Twenty-first Ann. Rep. Conn. Agr. Exp. Sta. 

 (1897), 175-181; Prillieux et Delacroix, Gompt. Rend, de I'Acad. Science, 

 129: 744-745; and Stewart, F. C, Bot. Gaz., 72: 129^130. 



