CHAPTER IV. 



FUNGOID DISEASES OF POTATOES. 



I. Potato Disease {Phytophthora infest ans). 

 Class : PiivcoiMVCETE/E ; Order : Pekonosporales. 



It is also known as potato blight, rot, demic, 

 etc., all being- names given to the disease caused by 

 Phytophthora infestans. It was first noticed in the 

 United States about the year 1840, and in Great 

 Britain in ICS43. Serious damage was not done 



Fig. 21 (A), — Part of a potato leaf with the dark disease spots caused 



by PhytophtJioi'n infestans. 



until the wet summer of 1845, when practically the 

 whole area under potatoes suffered. 



75 



