Harvesting and Storage 181 



stock, and frequently sweet potatoes are used for seed 

 purposes which are diseased when they are bedded. 

 Such potatoes are sure to produce diseased plants, which 

 in turn carry the disease to the field and often trans- 

 mit them to the tubers. Black-rot is the coromonest dis- 





FiGlTEE 24. — Outdoor storage pits commonly used for keeping 

 small quantities of sweet potatoes. Note proximity of pits to 

 hotbeds, a bad location from the disease standpoint. 



ease affecting the sweet potato conveyed in this manner. 

 Such diseased potatoes will be diificult to keep under any 

 conditions. (See Fig. 24.) 



Vine and draw potatoes. — A very important means 

 of controlling sweet potato diseases and preventing their 

 spread is by the use of vines as a means of propaga- 

 tion. The general plan now followed by most success- 

 ful growers is to plant a small seed patch with draws 

 or plants, and from this first planting cut vines to set 

 out the remaining acreage. In this way, no disease 

 which might have been present in the plant-bed is caj> 

 ried to the field. Potatoes propagated by means of 

 vines seem to keep better, generally speaking, than those 



