DISEASES OF GINSENG. 65 



stem, penetrate the epidermis of the host, and push through the 

 tissues within, branching and fornning- the mycelium above de- 

 scribed. It is only the ginseng plant, however, that this germ-tube 

 is able to penetrate and develop in, and this fungus is therefore never 

 found causing a blight of other plants. Alteriiarkc prmax. is able 

 to live as a parasite only upon the ginseng plant, and the very 

 common opinion among growers that this fungus lives upon weeds 

 or potatoes, etc., and spreads from these to ginseng, is without any 

 foundation in fact, so far as we know. That this fungus is the 

 genuine and only cause of the disease, has been repeatedly proven 

 by inoculations, that is, placing spores of the .Alternann, on the 

 leaves and stems of healthy plants. The disease invariably appears 

 in from four to ten days- That it will not affect the potato, for 

 example, has been indicated by repeated failures to produce 

 diseased spots by inoculating healthy potatoes with the spores of 

 the fungus. 



LIFE HISTORY OF THE PARASITE. By life history is meant 

 the development and habits of the fungus during the seasons, 

 spring, summer, autumn and winter. The facts of its history 

 must be at least fairly well known before efficient methods for its 

 control can be fully worked out. The manner in which the spores 

 of the fungus first find their way into the gardens varies in differ- 

 ent cases. In many cases, the parasite has doubtless been brought 

 in with wild plants from the woods. The writer has already re- 

 ferred to the fact that he has observed it on ginseng plants in the 

 woods- In some, it seems quite certain that the spores have been 

 carried from diseased gardens to healthy ones on the clothes of 

 persons visiting the gardens- That the fungus may be introduced 

 into a new garden with seed, is possible, but judging from careful 

 observations extending over several years that is, to say the least, 

 not at all common. The writer has never observed a single case 



