THE POTATO. 



Fungi and Bacteria Affecting the Potato. 



LATK BIvIGHT OR DOWNY MILDEW, EARLY BLIGHT OR 



LEAE SPOT DISEASE, BACTERIAL BLIGHT, THE 



POTATO SCAB, ETC. 



THE diseases of the cultivated plants caused by fungi inflict upon 

 agriculture an enormous loss. Scientific investigation has been 

 carried on by the governments in various parts of the world, and 

 the recent experiments in spraying with arsenites for the destruc 

 tion of insects, and the copper solution or Bordeaux mixture for the 

 treatment of fungous diseases, proves that a large proportion of this en- 

 ormous loss might be saved by their applications. 



This chapter is devoted to the fungous enemies of the potato. The 

 enemies of our fruit plants and trees are described under "FRUIT 

 CULTURE." 



I<ate Bliglit or Downy Mildew. This disease is caused by a 

 fungi, (phytophora infestans) which generally appears rather late in 

 in the season. Its attacks are usually sudden and fatal, the plants that 

 are affected often being entirely destroyed in a few days. 



The tubers are usually affected; rotting and giving off during the 

 process a foul odor. This disease spreads very rapidly during warm, 

 moist weather, and at such times it is very destructive. 



The first indication of its presence is the appearance of brownish spots 

 upon the leaves in the shape of a downy mildew. These spots grad- 

 nally enlarge and finally the whole leaf turns dark brown or blackish. 



