Ql8 



Rural Sciiuol Leaflet 



The scab is another disease that hurts the sale of potatoes. To prevent 

 it, soak the seed for two hours in a solution of a pint of formalin in thirty 

 gallons of water, and then plant on clean ground. 



Care must be taken not to dig potatoes for winter storage until the tops 

 have been dead ten days or more. Blight germs from the leaves may rot 

 the tubers, especially in wet weather. 



Potatoes in storage should be kept cool and dry, particularly if intended 

 for seed. Loss from shrinkage, rot, and loss of vitality of the seed is 

 least if the temperature can be kept just above freezing. 



TWO DISEASES OF THE POTATO PLANT AND THEIR CONTROL 



M. F. Barrus 



As has already been shown, the potato is one of the most important 



plants grown in the State. 

 Whatever affects its vigor or 

 destroys its growth, reduces 

 the yield and therefore is of 

 exceeding interest to us.* In 

 this article are presented the 

 stories of the downy mildew and 

 the scab, the two most common 

 and destructive diseases of the 

 potato. 



THE DOWNY MILDEW OF 

 POTATOES 



History. — The downy mildew 

 originated in South America, 

 the home of the potato, and 

 probably was early associated 

 with that plant. It did not 

 attract general attention until 

 1845, when the potato crop in 

 England, Ireland, Scotland, and 

 other countries of western 

 Europe, and also in the northern 

 United States, was nearly or 

 entirely destroyed by its ravages. This destruction of the potato crop 



*Of the diseases affecting this plant the following may be mentioned: early blight, a disease affecting 

 the leaves; downy mildew, or late blight and rot, affecting the leaves, stems, and tubers; Fusarium 

 blight and rot, affecting the vines and tubers; rhizoctonia, affecting the stem and forming a scurf on 

 the tubers; scab and bacterial rot, affecting the tubers only. 



Potato lea} affected by the downy mildew 

 (After Geneva Bui. 241, Plate XII) 



