B. P I.— 665. 



THE RUSTS OF GRAINS IN THE UNITED STATES. 



INTRODUCTION. 



That rusts are among the most serious diseases of grains in the 

 United States is generally granted. As they are always present 

 in humid grain-growing districts to a greater or less extent, it is 

 almost impossible to make accurate estimates of the damage caused 

 by them. Estimates are, perhaps, more often too low than too 

 high, so that the losses of fifteen to twenty million dollars annually, 

 estimated by Bolley (28/ p. 615) for the United States, certainly 

 seem within reason. Xumerous references to losses from rust epi- 

 demics in different countries may be found. 



The most severe epidemic in the last decade occurred in the 

 United States in 1904. It was particularly prevalent in the spring- 

 wheat belt of the northern Mississippi Valley, where the three States, 

 Minnesota, South Dakota, and North Dakota, in which the bulk 

 of the hard spring wheat of the United States is raised, suffered per- 

 haps more than any other section of the country. Table I shows a 

 comparison of the wheat crop in these three States for the years 1903, 

 1904, and 1905, affording a basis for an estimate of the losses sus- 

 tained in this epidemic. • 



Table I. — Wheat crop in Minnesota, South Dakota, and Xorth Dakota in 1903, 1904, 



and 1905* 



Year. 



Acreage. 



pe™re. Total yield. 



- 

 1903 



13, 167, 110 



Bushels. 

 13.15 

 11.65 

 13.66 



Bushels. 



173.146.171 



1904 



13. 193, 695 

 14.069,251 



153.793,233 



1905 



192. 190. 759 







* Compiled from U. S. Crop Report. 



Average yield per acre for 1903 and 1905=13.4 bushels; for 1904=11.65 bushels. 

 Reduction in yield per acre in 1904 below the average for 1903 and 1905=1.75 bushels. 

 Total reduction in yield in 1904=13,193,695 (acres) XL 75=23,088,966 (bushels). 

 Average price for the three States for 1903 and 1905=66.8 cents. Reduction in value 

 in 1904 below the average for 1903 and 1905=23,088,966X66.8 cents=S15,423,429."28. 



1 The serial numbers in parentheses throughout this bulletin refer to the titles in the " Bibliography " on 

 pages 79-82. 



216 7 



