m^ m~-tr- 



\\ 



^ M^ ^ uM M M 



Figure 32. Antagonism of soil organisms against parasitism of P. 

 volutum on Jgrostis. From van Luijk (906). 



Figure 33. Inhibiting eflFect of sterilized liquid medium of P. exfan- 

 sum versus Pyth'mm de Baryanum on lucerne. From van Luijk (906 ) . 



