452 SOUTHERN FIELD CROPS 



430. Example of a sweet-potato house. — Storage 

 houses may vary in capacity from a few hundred bushels 

 to several thousand. The construction and management 

 of such a house, used by an Alabama farmer, may serve as 

 an example. The essential features of such a house are 

 the following : (1) double walls filled with sawdust and a 

 layer of sand or sawdust above the ceiling; (2) one or 

 more ventilators, and transoms over the doors ; (3) bins 

 slatted on all sides and bottoms, so that the air has free 

 access. Figure 196 supplies additional information regard- 

 ing some of the details. 



An ordinary stove is placed in this house, with stove-pipe and 

 flue. For the first few weeks after the potatoes are stored, fire 

 is kept burning to drive off surplus moisture and to prevent sweat- 

 ing. Again, in cold or damp weather in winter, fires are main- 

 tained in order to keep the air inside warmer and dryer than that 

 outside. In this latitude the main purpose of fires and of a 

 ventilator is to prevent the condensation of the moisture of the 

 air upon the cool surface of the potatoes. The temperature 

 within this particular house varies between 40° and 70°, after the 

 curing process is complete. In the sweet-potato districts, where 

 such houses are in common use, the temperature for the first 

 few weeks is kept at about 90° F., during which time ample 

 ventilation is given to carry off the evaporated moisture. The 

 preferred winter temperature within a sweet-potato house is 

 around 50° and always, if possible, below 65°. 



Enemies 



431. Insects. — The sweet-potato has relatively few 

 very injurious insect enemies. However, in some fields in 

 Texas and Louisiana the sweet-potato root-borer or weevil 

 {Cylas formicarius) is very destructive, since it txmnels 



