irs 



It has been estimated that during the year 1921 the scab disease 

 caused a reduction of i per cent in the state's wheat yield; leaf rust, 1 

 per cent; stem rust, 0.5 per cent; loose smut, 3 per cent, and all other 

 diseases, 1 per cent. These, when added, give a total reduction of 9.5 

 per cent. The actual wheat yield of the state for that year is reported 

 to have been •15,234:,000 bushels. By considering that the absence of 

 disease would have resulted in an ideal, or 100 per cent, yield so far as 

 damage from disease is concerned, it can be seen that with diseases pres- 

 ent the actual yield was only 90.5 per cent of the ideal. A 100 per cent 

 yield may then be calculated as 49,982,000 bushels. With this figure as 

 a basis the probable losses from disease-attack can be transferred from 

 indefinite percentages to their more concrete and understandable equiva- 

 lents in bushels. Thus an estimated reduction of 4 per cent from scab 

 infection becomes equivalent to 1,999,000 bushels; and a 3 per cent re- 

 duction from loose smut infection becomes equivalent to 1,499,000 bushels 



With the exception of the year 1923, the loss figures showing per- 

 centages and bushels have been taken from '"The Plant Disease Bulletin. 

 Supplement : Croj) Losses from Plant Diseases in I'he United States". 

 This is a publication issued by the Plant Disease Survey of the United 

 States Department of Agriculture. It is based upon information supplied 

 from each state by persons interested in, and familiar with, crops and 

 their diseases. 



Equivalent valuations have been figured in all cases in terms of the 

 market price, usually as of December 1, rejOTrted by the State Agricul- 

 tural Statistician in the "Illinois Crop Report.s". 



Observations which have been introduced in order to show how prev- 

 alent and how destructive diseases may become should serve a further 

 purpose — that of impressing upon the individual farmer his need for 

 taking every available precaution to prevent the occurrence of similar 

 devastating outbreaks among his own crops. 



Diseases of Cereals 

 Wheat 



Under average conditions wheat ranks third among the cereal crops 

 of Illinois in acreage and i)roduction, and second in value. Its place in 

 the system of crop rotation suitable to Illinois soils is so difficult to fill 

 with other crops that its continued importance is assured. Both spring 

 and winter wheats are grown in the state, the latter in all j)arts of the 

 state and the former in only the northern third. About three million 

 acres are devoted to wheat each year, ai)proxiniatcly ]()0,0<I0 of which 

 are seeded to spring wheat. The importance of the wheat acreage in 

 various parts of the state is indicated on Majj 1. Since 1921 there has 

 been a steady increase in acreage, due no doubt to a more general use 

 of such satisfactory hard winter- varieties as Turkey 10-110, Kanred, and 

 others. The estimated value of the wheat crop in Illinois has varied in 

 recent years from $16,000,000 to $r2,000,000. 



