CEBEALS 339 



scattered kernels are affected. The mycelium is white and 

 sparse. 



Blight {Bacterium sp.). — This disease was under the 

 observation of Professor Burrill of Illinois for some time 

 prior to 1889 and was described by him in that year. 



It shows chiefly as a dwarfed condition which may occur 

 upon plants scattered throughout the field or more often 

 upon plants in certain spots in the field, such sick spots 

 varying in size from a few rods to an acre or more. The 

 affected plants appear abnormally slender, finally cease 

 growing, turn yellow, and most of them die. In rare 

 instances they may recover. 



The lowest roots of diseased plants, in some cases com- 

 prising half of the root system, are dead or dying. The 

 stalk near the base, when split lengthwise, shows a uni- 

 form dark color which also appears in the upper nodes 

 in lesser degree. The internodes show no disease symp- 

 toms. Upon the surface of the stem base are brownish, 

 corroded spots, diffuse or definitely bordered, and ac- 

 companied frequently by masses of rather firm semi- 

 transparent jelly. 



The leaf sheaths show watery brown or red specks or 

 larger irregular patches. Upon the insides of the sheaths 

 these spots are more conspicuous and larger, and are coated 

 with a gelatinous substance. 



The ears are sometimes affected in plants which are 

 taken with the disease so late as to allow ears to form. All 

 parts of the ear appear wilted and gelatinous coated, and 

 the silk rotten, though not ill scented. 



Wilt, pseudomonose {Pseudomonas Stewarti E. F. 

 Smith). — This corn wilt was first described by F. C. Stew- 



