181 



of spring stem-rust infections. That the barberry does initiate some of 

 the northern infections is apparent, since stem rust makes its appearance 

 in the north and in the south almost simultaneously. In 1!)23 the first 

 rust infection was found in .southern Illinois June 4 and in northern Illi- 

 nois June 7. The severity of the northern winter makes it unlikely that 

 northern infections could arise simultaneously with southern infections 

 without the presence of the barberry. Stem-rust infection has been found 

 on the barberry in '^3 counties,^ as shown on Map 4. Most of these 

 counties lie in the northern tiiird of the stale, and it is the belief of those 

 engaged in the eradication of the barberry that local ei)ideniics of stem 

 rust are traceable to the barberry. Undoubtedly eradication of this shrub 

 northward will result in a marked reduction of stem rust, and the losses 

 it occasions, in that section of the stale. 



Smut Diseases 



Three of the four smut diseases of wheat occur in Illinois. They 

 are widely distributed over the slate, and cause a considerable cro]) loss 

 each season. Two of them affect the wheat heads, while the third at- 

 tacks the leaves. 



Stinking Smut 

 Caused by Tilleiia lacvis Kiihn 



Stinking smut, also known as "bunt", fills the grains with a black 

 mass of fungus spores without changing the .external appearance of the 

 head. The apj)earance of diseased heads is nearly normal, and usually 

 it is not until the wheat is harvested that the jiresence of the disease is 

 discovered. During threshing many of the infected grains are broken, 

 and the liberation of the smut is accompanied by a very noticeable foul 

 odor. 



The first record of stinking smut in Illinois is a specimen collected 

 by G. P. Clinton at Urbana June 30, 1892. July 28 of the .same year 

 N. W. Ciraham collected the tlisease at Carhondale. During a field sur- 

 vey made in 1!)18 by the Office of Cereal Investigations of the United 

 States Department of Agriculture 51 fields examined in Illinois showed 

 an average of 1.8 per cent of diseased heads, but the distribution of 

 infection is not apjjarent from the report. In a second survey, made in 

 1 !)]!), among 98 fields examined in Illinois the heaviest stinking-smut ' 

 infection found was 24 per cent, and the average for all fields was O.li 

 per cent. 



From the estimates of cro]) losses shown in Table 9 the seriousness 

 of this disease is ap])arent. Loss from stinking snnit is caj)able of accu- 

 rate estimation, since each infected head is entirely destroyed. Hence 

 the percentage of infected heads in a field represents the loss in yield 



' Recent infoimatinn on the occiiiivnoe of uteni-rust infiction on {he haibi'rry was 

 furnished by Gordon C. Curran, State Leader of Barberry E?radicatlon In Illinois. 



