FACTORS INFLUENCING THE PATHOGENICITY 

 OF HELMINTHOSPORIUM SATIVUM 



A THESIS 



SUBMITTED TO THE FACULTY OF THE GRADUATE 

 SCHOOL OF THE UNIVERSITY OF MINNESOTA 



BY 



LOUISE DOSDALL, M.A. 



IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE 

 DEGREE OF DOCTOR OF PHILOSOPHY 



JUNE, 1922 



