103 



Fungous Enemies of the Sweet Potato in Indiana. 

 By C. a. Ludwig. 



In the spriiifz: uf 11>]1. the \M-iter began :iu investigntion tu determine 

 the causal organism (it a (h'.v I'nt wliich (h)es damage to sweet potatoes in 

 storage at liis Iiome in Franklin County, Indiana. The worlv was contin- 

 ued the following winter as thesis work for a baccalaureate degi'ee at 

 Purdue Tniversity ; and as no special study uf the fungi affecting sweet po- 

 tatoes in Indiana could be found, the subject was enlarged in scope to take 

 in all the fungi of Indiana which are known to affect stored sweet 

 potatoes. A number of forms which have been suggested as the cause of 

 der-ay, and some not thus previously associated have been studied ; and 

 certain notes concerning them may not be without interest, in spite of the 

 fact that the primary cause of the dry rot still remains in doubt. The work 

 was carried on in the botanical laboratories of the Purdue Agricultural 

 Experiment Stafion, and the writer wishes to acknowledge his indebted- 

 ness to the members of the botanical staff and to a number of other 

 friends for various assistance. 



Tlie following fungi were found to affect stored sweet potatoes in 

 Indiana : 



Phycomycetes. 

 RMzopus spp. 



ASCOMYCETES. 



Xcrtrid Ipoiiidd Hals. 



PeniciUiidu spp. 



Diaporthc hatatatis Ilarter and Field. 

 Fungi Imperfecti 



t^ph(viO)iC)na pnihridtinii ( Fll. and Hals.) Sacc. 



Fusariuvi spp. 

 Rhlzopus nifiricoiis Ehr. is the cause of a soft rot of sweet potatoes 

 when they are kept too damp. It was determined as the cause of soft 

 rot in some specimens from Tippecanoe County. Some other species of 

 Rhizopus were also isolated from potatoes aft'ected with soft rot, a circum- 

 stance which makes it probable that they may also be the cause of a soft 

 rot when conditions are favorable for their growth. 



