PLATE 23 



A. — A sweet potato with four blackrot spots caused by Sphaeronema fimbriatum 

 taken from a storage house in November. 



B. — ^The same sweet potato shown in A after being kept in an ice box for two months. 

 The temperature of the ice box was about the same as that recommended for the storage 

 of sweet potatoes. Note that the spots have enlarged and imited so as to involve 

 nearly the entire potato. 



