179 



Agriculture and the Indiana Agricultural Experiment Station indicate 

 the possibility of developing rust-resistant strains from the soft wheats, 

 and the already-proved occurrence of these strains in such varieties as 

 Fulcaster, Fultz. and Red Cross should be especially encouraging to the 

 wheat growers in our own soft wheat regions. 



Stem Rust 



Caused by Puccinia graminis Pers. 



The second of the two rusts occurring on wheat in Illinois is stem 

 rust, variously known as "rust," "black-stem-rust," "black rust," and "red 

 rust." During the early spring this rust appears upon growing wheat 

 plants, showing as red eruptions upon the stems and leaf sheaths. These 

 eruptions are distinguishable from leaf-rust spots in part by their location 

 upon the stems, hut more certainly by their appearance. They are usually 

 two to four times longer, or more ; the quantity of spores seems greater 

 and more bulging; and the epidermis appears torn and ragged around the 

 edges of the spots. 



Just previous to the maturity of the wheat this rust, like the leaf 

 rust, develops a resting stage, the spots of which appear much the same 

 as those of the red stage in size and shape, but are black. This black 

 stage, or "black rust," serves to carry the fungus through the winter 

 months and to furnish infective material for the production of the alter- 

 nate stage upon the common barberry in early spring. Recent propa- 

 ganda on barberry eradication in the north-central states has made the 

 life history of this fungus, its seriousness as a crop pest, and its preva- 

 lence in wheat regions matters of common knowledge. 



Of the cereal rusts occurring in the United States, stem rust is un- 

 doubtedly the most important. It is estimated that since 1918 the crop 

 reduction for the United States in any one year from this source has not 

 been less than 804,000 bushels. In Illinois, however, stem rust is not, dur- 

 ing average years, the serious menace that it is in the grain states of the 

 north and west. Nevertheless the annual toll taken by this disease in 

 Illinois is one not to be overlooked. Burrill' estimated that in 188.") the 

 loss from stem rust in lUinois amounted to $1,875,000, and in l!)]; W. P. 

 Flint reported a loss of 10 to 20 per cent of the crop. Estimates of loss 

 in Illinois for the years 1918-1923 inclusive have varied as indicated in 

 Table 5, from a trace in 1918 and 1922 to 901,800 bushels in 1923, valued 

 at approximately -$829,000. 



The history of stem rust in Illinois is more definitely traceable than 

 that of any other disease. The first record of occurrence is a specimen 

 collected by A. B. Seymour in McLean county July 11, 1881. During 

 the same season Seymour collected slem-rust specimens in Marshall, 

 McHenry, Piatt, and Tazewell counties, indicating that at that time the 

 disease had a wide-spread distribution over the northern half of the state. 



•See Stevens. F. U. Diseases of economic plants. (1921) p. 12. 



