Potatoes 207 



Often there appears a moldy, downy growth on the surface 

 of the leaves. This has given rise to the name, downy mildew, 

 which is often used for the late blight. The spores of this 

 white growth multiply rapidly and are easily scattered by the 

 wind, which is one reason for the rapid spreading of late blight. 

 The remedy is to spray with bordeaux mixture, and to be 

 effective the spraying should be done early in the season before 

 the blight starts. In New York late blight usually occurs 

 any time after the first of August. In regions farther south 

 it may appear earlier. 



Potato scab. The chief fungous disease that attacks the 

 tubers is -scab. The surface of a scabby potato is rough and 

 broken. To combat the disease the seed pieces are disinfected 

 before they are planted. This is usually done by soaking them 

 for two hours before they are cut in a solution of one-half pint 

 of formalin to fifteen gallons of water. Another method is to 

 soak them for an hour and a half in a solution of bichloride of 

 mercury made by dissolving twelve ounces in fifteen gallons of 

 water. 



SWEET POTATOES 



117. Distribution and use. Sweet potatoes are of tropical 

 origin, and require a warm climate. The bulk of the commercial 

 crop is grown in the South ; the only state outside of that sec- 

 tion producing any large quantity is New Jersey. The states 

 growing large crops in the usual order of the amount of their 

 production are Georgia, North Carolina, Alabama, Mississippi, 

 Virginia, South Carolina, Louisiana, Texas, Tennessee, and 

 New Jersey. 



Although the sweet potato is a perennial, it is cultivated as 

 an annual. The part used for food is the fleshy root. The 

 plants seldom produce flowers or seeds and they are propa- 

 gated, except in the case of new varieties, by division. The 

 chief use of the roots is as human food, but they are sometimes 

 fed to live-stock, especially hogs. 



