185 



It appears at the flowering time of wheat. The glumes, flowers, and 

 grain are entirely destroyed, and their place is taken by a loose mass of 

 olive-green or black powder. By harvest-time nothing remains but a 

 little black powder on the top of the stalk where the head should have 

 developed. 



The black powder on the diseased heads is blown by the wind to the 

 flowers of healthy plants, infecting them with the disease, and as the grain 

 develops, it also is infected. When such an infected grain is used for 

 seed it produces a plant bearing a black head, from which no new grain 

 can be harvested. The infection is carried in this way from crop to 

 crop inside the seed. 



The earliest records of loose smut in Illinois are specimens collected 

 by A. B. Seymour in McLean county June 2T, 1879, and in Champaign 

 county June 5, 1882. Later collections were made in Champaign county 

 in 1888," 1889, 18!)1, and 181)2. 



The distribution of this disease, so far as it is known to us at the 

 present time, is shown on Map 6. It is known to occur in 55 counties, 

 most of which lie in the southern two thirds of the state and comprise the 

 wheat-producing section. 



Loose smut is an important factor in lessening the production of 

 wheat in Illinois. Over a period of seven years there has been, as is 

 shown in Table 1-i, a yearly infection, and consequent loss ranging from 

 1.5 per cent or 8r)!),()o6 bushels in 1923 to 3 per cent or 1 ,G41:,()()0 bushels 

 in 1922. The average annual loss for the 7-ycar period from loose-smut 

 infection was 2.43 per cent. 



In 1922 an examination of 81 fields, summarized in Table 15, in- 

 dicated an average loose-smut infection of 2.13 per cent. These fields 

 were distributed among 2G counties and included 175(5 acres. 



A similar examination in 1923 indicated, as shown in Table 1<), an 

 average loose-smut infection of 1.56 per cent in 254 fields distributed 

 among 40 counties. A total of 4,849 acres was covered, averaging slight- 

 ly more than 118 acres for each of the 40 counties. 



The average production of wheat per acre in 1923 was 18 bushels. 

 On a farm growing 20 acres of wheat the production would be 3()0 bush- 

 els. However, this is only 98.44 per cent of what the crop might have 

 been had loose-smut infection not been present. Production without smut 

 should have been slightly more than 3()5.7 bushels, or an increase in yield 

 of 5.7 bushels, worth in cash $5.35. This increase is equivalent to the 

 crop harvested from 0.32 or nearly '/s of an acre ; hence the farmer 

 stands to lose not merely $5.35 worth of salable grain, but also the cost 

 of grain production for nearly '/^ of an acre for the entire sea.son. The 

 total of the two is an item not to be overlooked in the economics of pro- 

 duction, whether from the standpoint of the individual farmer or from 

 the sland])oint of the state's agricultural interests. 



Control of loose smut, while attended with some difficulty for the 

 inexperienced, is thoroughly practicalile and should be much more cmii- 

 nionly undertaken. Seed should be thoroughly cleaned, and then soaked 



