Nov. is, 1915 
Sclerotinia Spp. on Ginseng 
295 
PATHOGENICITY 
In the spring of 1912 the writer received a number of black-rotted roots 
from Wisconsin showing various stages of development of the disease. 
Isolations were made from these roots by making plantings from the 
inner tissues of the roots on poured plates of hard potato agar. The 
fungus was obtained in pure culture, where it produces a characteristic 
black growth. 
Inoculations on healthy roots made at various times during the summer 
gave negative results, as would be expected from the nature of the fungus, 
since the disease always develops in beds during the winter. In October 
of the same year (1912) six roots were washed clean and inoculated by 
placing a piece of the agar pure culture in a small cut made in the tissues 
of the root. Three similar roots were injured and used as checks. All 
the roots were planted in soil which had never grown a crop of ginseng. 
The following March an examination of the roots showed the character¬ 
istic symptoms of the disease. Some were entirely black, while others 
were only partly blackened. The fungus was easily reisolated from these 
roots. Plate XXIX, figure 1, shows two inoculated roots, together with 
a check root. One of the inoculated roots is entirely black, while the 
second shows this black color only in part. 
In October, 1913, inoculations were again made on ginseng roots. 
These roots were not injured, but the fungus was placed on the old stem 
scar. The next March the roots were black, as in the previous year. 
Reisolations were again made, and the fungus which was obtained pro¬ 
duced the characteristic black growth. 
IDENTITY OF THE SPECIES 
The growth of the fungus in culture and the general behavior of this 
organism differed so greatly from the known species of Sclerotinia that 
it has always been an interesting question as to the source of the fungus 
which appeared in isolated gardens throughout the country. One plau¬ 
sible explanation is that the fungus, being associated with wild ginseng 
roots or with one of the common weeds, was brought in from the woods, 
as many growers make a practice of using leaf mold in preparing their 
beds. Since the fungus from the description resembled Sclerotinia 
smilacina Durand, it seemed advisable to determine whether the species of 
Sclerotinia on ginseng could produce a black-rot of the rhizome of 
Smilacina spp. and w'hether the two were also identical in other respects. 
Inoculations on species of Smilacina. —In October, 1913, six 
rhizomes of Smilacina racemosa were inoculated with a pure culture of 
the black-rot fungus obtained from ginseng. The inoculations were made 
by slightly injuring the rhizome and inserting the mycelium of the fungus 
in the cut. Check plants were also injured. When examined the follow¬ 
ing March, the rhizomes showed the characteristic symptoms of black-rot 
