PATHOGENICITY AND IDENTITY OF SCLEROTINIA 

 LIBERTIANA AND SCLEROTINIA SMILACINA ON 

 GINSENG 



By J. ROSENBAUM,' 



Mycologist, Cotton and Truck Disease Investigations, 

 Bureau of Plant Industry 



INTRODUCTION 



For a number of years two species of Sclerotinia have been recognized 

 as probable causes of the rotting of ginseng roots {Panax quinque folia), 

 but the pathogenicity and identity of these fungi have not been proved by 

 by inoculation experiments. 



The purpose of this paper is (i) to report inoculation experiments 

 establishing the pathogenicity of these organisms, and (2) to detail 

 the experimental data and considerations on which the conclusions as to 

 the identity of the two pathogens are based. 



WHITE-ROT OF GINSENG 



The white-rot of ginseng was first reported by Whetzel (1907, p. 89). ^ 

 Sclerotia were found, but the identity of the fungus was not determined. 

 Subsequent workers, Rankin (1910), Osner (191 1), and Whetzel and 

 Rosenbaum (191 2, p. 34-45) have attributed the disease to Sclerotinia 

 lihertiana Fuckel. These writers based their observations on the associa- 

 tion of the sclerotia of the fungus with the host and the general resem- 

 blance of the organism on the host and in culture to the widespread 

 Sclerotinia lihertiana. No inoculation experiments have been reported. 



PATHOGENICITY 



During the spring of 191 3 the fungus was isolated from diseased gin- 

 seng roots grown at Newtown, Pa., Mentor, Ohio, and Edenville, Mich. 

 The isolations were made by washing the roots, immersing them for 10 

 minutes in a solution of mercuric chlorid (i to 1,000), peeling back a por- 

 tion of the external tissues, and transferring small bits of tissue from the 

 inside of the root to poured plates of hard potato agar. Pure cultures 

 were obtained in the majority of cases from the first planting. In addi- 

 tion to the cultures isolated from ginseng, inoculations on healthy ginseng 



' The writer is indebted for many suggestions to Dr. Donald Reddick. of Cornell University, under whose 

 dirertioa this work was done. 

 2 Bibliographic citations in parentheses refer to " Literature cited," p. 297. 



Journal of Agricultural Research, Vol. V, No. 7 



Dept. of Agriculture, Washington, D. C. Nov. 15, 1915 



as G— 66 



(291) 



