CHARACTERISTICS OF SOME FORAGE-GRASS DISEASES 



13 



Leaf Blight 



Leaf blight, caused by Helminthos- 

 perium turcicum Pass., is a serious fungus 

 disease of corn and sorghum in some areas 

 of the United States and is destructive on 

 Sudan grass in the North Central region. 

 As its name implies, symptoms are a con- 

 spicuous blighted or scalded appearance of 

 the foliage (fig. 14). Within a period of a 

 few days an entire field of Sudan grass 

 may develop extreme blighting and appear 

 characteristically burned or frosted. Coni- 

 dia of the fungus are produced in abun- 

 dance on the lesions. Conidia are dark, 

 slightly thickened, with one to eight 

 septations, and have a distinctly protrud- 

 ing hilum at the basal end. Blight first 

 appears about midsummer and continues 

 until plant maturity. Disease develop- 

 ment is favored by periods of warm, 

 moist weather. 



Figure 14. — Leaf blight on 

 Sudan grass. 



