THE INDIAN CORN RUST 207 



been recommended, but the failure of Professor Keller- 

 man's experiments, in attempting to increase the amount 

 of smut by rolling the seed in the spores, indicates that 

 this is hardly worth while, especially as the copj)er sul- 

 phate soaking has the effect of diminishing the vitality 

 of the seed. If treatment of this kind were desirable, it 

 would be better to adopt the hot water method used to 

 destroy the smut of oats and wheat. From the fact that 

 the smut enters the plant when very young, we should 

 hardly expect that spraying the growing corn with the 

 Bordeaux mixture, or other fungicides, would do any 

 good ; and recent experiments confirm this supposition. 

 Literature. — An excellent general account of corn 

 smut, by Professor A. B. Seymour, may be found in 

 the 1887 report of the Department of Agriculture 

 (pp. 380-389). 



The Indian Corn Rust 



Piiccinia maydis 



The disease of Indian corn known as rust has at" 

 tracted comparatively little attention from American 

 farmers, and, so far as its injuries are concerned, it is, 

 indeed, of minor importance. It is fortunate that this 

 is the case, for, as yet, no successful method of combat- 

 ing it has been suggested. 



Corn rust is quite similar, in character and appear- 

 ance, to the familiar red rust of wheat and oats. It 

 usually appears about midsummer, in the shape of small, 

 brownish, dust-like blotches on the surface of the corn 

 leaf. These dust-like patches, or pustules, consist of 

 the summer spores of the fungus ; the spores are of a 

 rich yellowish brown color, and are easily blown aw^ay by 

 the wind. Tow^ard the end of summer these brownish 

 spores are replaced by blackish ones, so that the pustules 

 then assume a blackish apj^earance. These dark-colored 



