GRASSES OF IOWA. 



185 



Fungus Diseases of Grasses. 



A large number of our forage plants are subject to serious 

 fungus diseases, which materially lessen the crop. While these 

 diseases are most severe to the cereals, where they annually 

 entail a loss of millions of dollars, many of our best forage 

 grasses are subject to most destructive rusts and smuts. One 

 way to overcome these dangerous pests is in a study of their 

 life history to see if methods of culture cannot improve the 



Fig. 80. Downy mildew of millet (Sderospora graminicola.) The leaves partially 

 disintegrated; a, leaftmagDified; b, conidla; c, coDidiophore bearing conldia ^spores) 

 (Pammel and King.) 



Fig. 81. ScUrospora graminicola. Leaves torn up into shreds, filled with oospores, 

 (King.) 



