PATHOGENICITY AND IDENTITY OF SCLEROTINIA 
LIBERTIANA AND SCLEROTINIA SMILACINA ON 
GINSENG 
By J. Rosenbaum , 1 
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 quinquefolia), 
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). 2 
Sclerotia were found, but the identity of the fungus was not determined. 
Subsequent workers, Rankin (1910), Osner (1911), and Whetzel and 
Rosenbaum (1912, p. 34-45) have attributed the disease to Sclerotinia 
libertiana 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 libertiana . No inoculation experiments have been reported. 
PATHOGENICITY 
During the spring of 1913 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 (1 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 
1 The writer is indebted for many suggestions to Dr. Donald Reddick, of Cornell University, under whose 
direction this work was done. 
2 Bibliographic citations in parentheses refer to “ Literature cited,” p. *97. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
as 
Vol. V, No. 7 
Nov. 15, 1915 
G —66 
(291) 
