84 DISEASES OF GINSENG. 



summer time an ice box is necessary, as it cannot be grown at the 

 ordinary temperature. At a temperature of 40 degrees F. it grew 

 luxuriantly and fine sclerotia appeared on the plates. 



An attempt was made during the summer of 1909 to deter- 

 mine if this could be eradicated by some soil treatment. These 

 were only preliminary experiments and were not very extensive, 

 yet it was found that the fungus will grow on an acid or alkaline 

 culture medium equally well. This would seem to indicate that 

 the fungus should grow in either acid or aliialine soils. 



For the present it would be advisable to be on a sharp 

 lookout for black roots when digging in the fall. If any are found 

 search the area carefully and remove all of them and burn them. 

 Eemove the dirt in the affected area down to a depth of a foot and 

 and a half or more and replace it with new soil. Van Hook cited 

 a case where a grower had set roots in a bed from which black 

 roots were taken six or seven years before. The roots failed to 

 come up in the spring and when examined were found to be black 

 rotted, thus showing that the fungus is capable of remaining in 

 the soil several years. 



Soft Rot. 

 (Bacterium sp. & Fusarium sp.) 



The soft rot of ginseng roots is a serious disease which 

 causes considerable loss each year. The symptoms of the soft rot 

 are essentially the same above ground as the symptoms exhibited 

 by the tops suffering from "Fiber or End Rot." A successive 

 change of color from dark green to pale green, yellow and red 

 mark the advance of the soft rot as it eats into the root. The 

 above-ground conditions (Fig. 36) indicate the extent to which the 

 rot has progressed. When the rotting begins with the smaller 

 rootlets, the coloration of the foliage is the common indication, but 



