PLATE 17 



A. — A frequently encountered type of downy mildew effect. The maize plant is 

 sterile, with no ear borne in the normal place but with a couple of small, abortive ears 

 growing at the base of the tassel. The leaf sheaths are whitish yellow, and conspic- 

 uous stripes of the same color occupy a large proportion of the leaves. These are stiff 

 and brittle, the young ones at the top of the plant ascending at an unnatural angle 

 and the older ones breaking and hanging down stiffly. 



B. — A serious case of downy mildew injury, one of hundreds in a badly attacked 

 maize field. The conspicuous striping of the leaves and the crooked stalk at once 

 attract attention. The small ear is sterile. At the base of the plant can be seen 

 another one badly dwarfed by the disease. 



