288 



Diseases of Economic Plants 



Although the green stalks are not naturally susceptible, 

 the shanks are particularly so. 



The causal fungus gains entrance to the ears from attacked 

 stalks which bear them, and these are in turn infected 



Fio 



151. — Diplodia on old si 

 Burrill and Barrett. 



inks. After 



through the roots from the soil. Ears are also invaded 

 through the silks by wind-borne spores, which come, in part, 

 from diseased ears, but more largely from diseased stalks 

 left in the field. 



