253 



county. In 1922 and 1923 it was found in Jackson and Peoria counties, 

 where it appeared to injure from 1 to 5 per cent of the crop. 



Blight 



Caused by Psciidoinonas phascoli E. F. S. 



Bhght is a bacterial disease. It may be severe on the leaves and 

 pods, where it causes dark, water-soaked spots. It is known in 8 widely 

 scattered Illinois counties, the distribution of which is shown on Map 1 13. 



Rust 

 Caused by Uromyccs appcndiculatus (Pers.) Lev. 



Rust of the bean is especially a disease of the leaves, although it 

 occasionally attacks stems and pods. It appears as rusty spots or blisters, 

 which eventually break open, exposing a mass of rusty powder. 



It is known to have been present in Illinois since 1881, in which year 

 it was found by A. B. Seymour in Union county. 



It is now known in 6 counties, the distribution of which is shown 

 on Map 114. Apparently it is widely distributed, but is most common in 

 southern Illinois. 



Onion 



Approximately 1000 acres are devoted annually to the growing of 

 onions for commercial purposes in Illinois. The yield varies from 200 

 to over 400 bushels per acre, and the total production varies from 400 

 to 800 cars of 12.5 tons each per annum. It is estimated that of the 442 

 cars produced in 1921, 44 were sold in home markets and .■!9S were 

 shipped outside the state. 



Smut 



Caused by Urocystis cepulae Frost 



The one onion disease of importance in the field in Illinois is smut. 

 It is carried over in the soil from year to year, from which it attacks 

 only the seedling plants, causing dark stripes on the leaves, dwarfing, 

 death of the tops, and death of tlie bulbs. 



This disease was first reported in Illinois in 1918, when it was said 

 to have caused a 25 per cent crop injury acconi])anied by a 10 to 15 ])er 

 cent crop loss. Presumably the rejiort was made by J. C. Walker and 

 had to do with the Cook county onion district. The disease is now known 

 to occur in Cook and Peoria counties. 



Treatment for prevention consists in spraying the seeds with a 

 formaldehyde solution as they are being planted. 



Lettuce 



This crop, so commonly grown in home gardens, by local truckers 

 for their markets, and to some extent in greenhouses for winter-con- 



