320 Diseases of Economic Plants 



(Septoria sps.) is common as small, dark spots upon the chaff 

 of certain varieties of wheat. Another Septoria causes leaf- 

 spots, especially upon the lower leaves. Eel-worms ^""^^ ^^'■^' ^^'^ 

 (Nematodes) affecting the grain in the head have been found 

 in several states, in some fields causing 25 per cent damage. 

 Only clean seed should be used. Crop rotation is advised. 

 Ergot is occasional on wheat. The Southern-blight (Sclero- 

 tium) sometimes injures the stand in the South. 



