DISEASES OF GINSENG. 69 



to have any basis in fact. Our observations, extending over a 

 period of six years, and a careful consideration of tiie data present- 

 ed by growers convince us that shade and mulch have very little 

 to do with the appearance and severity of this disease in a garden. 

 Location may play some part, though much less than is usually 

 attributed to it. A garden so situated as to have good air drain- 

 age, or ventilation may, because the plants dry off more quickly, 

 escape the disease to some extent, or occasionally, but the grower 

 who depends upon his location instead of his sprayer, for the con- 

 trol of the blight, is booked to loose sooner or later. The type of 

 soil or kind of fertilizer used appear to be unimportant, as regards 

 their relation to this disease. Any of these factors, heat, shade, 

 mulch, soil, fertilizers, etc, are apt to be hit upon by the grower 

 as a source of his misfortune when disease takes his crop, because 

 of his lack of knowledge of the true nature of the malady, the 

 casual organism and the relation of the external conditions to its 

 development. Two factors appear to be of prime importance in 

 the case of this disease: the presence of the casual organism, 

 Alternaria pancuv, and the proper conditions as to moistin-e for 

 its development. 



CONTROL. While very satisfactory progress has been made in 

 the control of this malady, there still remains much to be done in 

 working out details and perfecting the methods and means now 

 employed for combating it. 



The various means now employed in combating the Alter- 

 naria Blight are based upon one of three of the fundamental prin- 

 ciples of plant disease control and may be discussed as follows: 



I. Exclusion of the fundus from the ginseng garden. 

 In most cases, it is now too late to take measures to prevent the 

 introduction of the fungus into the garden. It has already become 



