FUNGI IMPERFECTI 



307 



usually before the middle or latter part of the summer ; so that the 

 tops are not often killed before the middle of July or the first of 

 August in New York. The parasite does not pass down into the 

 root nor does it induce rot of any kind in the roots. The general 

 effect on the root of the plant is to reduce its growth, and proba- 

 bly where the blight continues year after year the root will be so 

 weakened that it will become subject to soil rots of various kinds. 



Fig. 139. Blight of Ginseng: a Severe Attack beginning when the 

 Plants were Young. (Photograph by H. H. Whetzel) 



Control. It has been clearly demonstrated that this disease may 

 be controlled by thorough spraying with Bordeaux mixture. The 

 application should begin early in the spring, as soon as the plants 

 come through the ground, and should be kept up throughout the 

 season every ten days or two weeks. It is particularly necessary 

 to spray the young plants frequently when they are coming through 

 the soil in order to protect them from the primary infection. It 

 has been shown that ginseng is able to stand a very strong solution 



