84 Journal of Agricultural Research voi. ni. No. 1 



In view of the serious nature of the disease and its sudden appearance 

 in America it has seemed best to present this preliminary paper. The 

 true parasitic nature of the fungus was evident from its effect on the 

 growing plants, but its parasitism was further demonstrated by the suc- 

 cessful isolation of the fungus from the interior tissue of thoroughly disin- 

 fected stems. Owing to limited time and opportunity for extensive field 

 observations, many questions relating to the pathological phase of the 

 subject remain unsolved. Problems pertaining to the method of infec- 

 tion by the fungus, its manner of dissemination, and control measures for 

 the disease are still subjects of investigation by the Office of Pathological 

 Collections and Inspection Work. 



PLATE XI 



A hemp plant, showing upper branches attacked by the fungus Bolryosphaeria 

 marconii. 



