THE POTATO IN BRITISH COLUMBIA. 



59 



POTATO-DISEASES. 



Diseases cause enormous losses to the potato-crop each year. In British Colum- 

 bia the diseases are not so widespread as they are in other parts of Canada ; there- 

 fore it is of all the more importance that growers make themselves more familiar 

 with the various diseases whicli attack the potato-crop and adopt the methods advo- 

 cated for their control. 



Fig. 56. An illustration to show where late blight started in an unsprayed 

 plot. Note the dead stalks of the blighted plants (original). 



Fig. 57. Sprayed and unsprayed potatoes. The unsprayed plants are dead, 

 while the sprayed are comparatively vigorous. 



Most potato-diseases are caused by fungi; some, however, are caused by bac- 

 teria, others by the effect of the weather, and others by unknown agents. 



Fungi, being unable to manufacture their own food, obtain their nourishment 

 from decaying animal or vegetable remains or from living plants and animals. 



