C( )NTENTS 



I XTMilH i ri(i\ 



Hi- roRY .......... 5 



I'm. 1:1 i m \\n Method of Attack ...... 9 



1 I \ Experi M ix i s 



Experimental Infection of Tubers ..... 10 



Experimental Infection of Living Plants .... 12 



Summary ......... 27 



II. Ecology ami Physiology of the Organisms 



i remperjiture Relations ...... 27 



2. Growth Habit 34 



:'.. The Carbon Sources of the Two Organisms . . . -'S4 



Conclusions . . . . . . . . . 42 



Bibliography ......... 43 



