DISEASES OF GINSENG. 67 



has reached a size sufficient to attract attention. These spots on 

 the stalks soon become covered with a velvety brown coat of spores 

 which are produced from the ends of the spore stalks that grow 

 out from the mycelium in the diseased tissues. When these spores 

 are ripe, they break away from the sporestalks very readily 

 and are carried, by the slightest breeze, through the garden. In 

 this way they reach the leaves, falling upon the upper surface, or 

 into the crotches formed by the base of the leaflets or by the leaf 

 stems at the top of the stalk. Here they lie inactive until there is 

 a rain or a heavy dew. Then they germinate and infect the leaf or 

 leaf stems as I have already described. Another crop of spores 

 is now formed, especially on the diseased leaf stem. Spores are 

 usually not produced abundantly on the spots on the leaves. This 

 second crop of spores serves to infect the seed heads, causing the 

 shelling of the berries. Spores are usually produced in great 

 numbers on the diseased seed stalks and shriveled berries. Many 

 parasitic fungi pass the winter by means of a different kind of 

 spore than that which is produced repeatedly to spread the para- 

 site through the summer. This does not appear to be the habit of 

 Jlternaria panax, at least we have thus far never observed any 

 winter spore-form- The fungus apparently passes the winter 

 commonly as hibernating mycelium in the old dead diseased stems. 

 The fungus is thus accounted for throughout the year. With these 

 facts before us, it should now be less difficult to understand its 

 sudden appearance in the ginseng garden and the relation of 

 weather, etc. to epidemics of the disease. 



ECOLOGY OF THE DISEASE. By ecoloiy is here meant the 

 relation of weather, location, shade, soil, mulch, etc., to the 

 appearance and severity of the disease. It is a too common belief 

 of growers that weather, soil, or some improper fertilizer is the 

 direct cause of diseases in their crops. This is seldom true, cer- 



