PLATE 27 



A. — A cross section of a sweet potato decayed by Mucor racemosus at a temperature 

 of 5° C. The mottled appearance is characteristic of rot caused by this fungus at low 

 temperatures. 



B. — A longitudinal section of a sweet potato decayed by Alternaria sp. The tissue 

 becomes a very dark brown to nearly black. 



C. — A portion of a sweet potato probably decayed by Penicillium sp. Note the 

 numerous cushions of the fungus on the surface. 



D. — A cross section of a sweet potato showing the characteristic appearance of the 

 rot caused by Botrytis cinerea. 



E.— A cross section of a sweet potato almost completely decayed by Epicoccum sp. 

 The netted string-like appearance, also the yellowish color produced at some stages in 

 the progress of the rot, is characteristic of the decay caused by this fvmgus. 



F — A longitudinal section of a partially decayed sweet potato. This so-called end- 

 rot is quite common in storage. Fusarium oxysporum is generally isolated from such 

 decayed tissue. Although this fungus is believed to be the cause of endrot, inocula- 

 tion experiments have never given consistent results. 



