452 SOUTHEEN 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 tunnels 



