THE POTATO 247 



toes do not differ materially from those employed 

 with ordinary farm and garden crops. 



"Aside from planting and harvesting, the work 

 of caring for a crop of sweet potatoes can be done 

 almost entirely by the use of ordinary farm and 

 garden tools. 



"The sweet potato is subject to injury from a 

 number of diseases. Those diseases causing rot 

 and decay are most prevalent and result in the 

 greatest loss during the period that the crop is held 

 in storage, Occasionally, however, the crop may 

 be lost before harvesting, and one form of rot, 

 known as black-rot, destroys the young plants, 

 attacks the potatoes while they are in the ground, 

 and causes them to decay while in storage. The 

 spores that are responsible for the several forms of 

 rot affecting sweet potatoes may remain in the soil 

 from year to year, or they may be carried over 

 winter upon the seed. Diseases are generally 

 introduced with affected seed or plants, and when 

 once established in the soil, the storehouse, or the 

 propagating bed it is doubtful whether they can 

 be eradicated except by the adoption of the most 

 thorough methods. 



"A disease known as stem-rot causes the stem 

 of the plant to begin to die at the surface of the 

 ground. This decay gradually extends downward 

 to the potatoes and frequently kills the entire 

 plant. 



"The diseases known as soft-rot, dry-rot, and 

 white-rot are all similar in their method of attack 

 to the black-rot. One form, known as soil-rot, 

 causes the loss of the crop while it is in the field. 

 Each of these diseases is caused by a particular 

 fungus, but has received the common name sug- 

 gested by its general appearance or some marked 



