LETTltR OF TRANSMITTAL 



U. S. Department of Agriculture, 



Bureau of Plant Industry, 



Office of Chief of Bureau, 



Washington, D. C, May 26, 1911. 



Sir: I have the honor to transmit herewith and to recommend for 

 pubHcation as Bulletin No. 224 of the series of tliis Bureau the accom- 

 panying manuscript, entitled "Timotlw Rust in the United States," 

 by Mr. Edward C. Johnson, of the Office of Grain Investigations of 

 this Bureau. 



Timothy rust, first reported in the United States in 1882, has 

 become an important problem in recent years. In 1906 it was abun- 

 dant in the timothy-breeding plats at the Arlington Experimental 

 Farm, near Washington, D. C. Since then it has become widespread, 

 causing considerable damage in many localities, and its ultimate dis- 

 tribution over all timothy-growing regions wdiere conditions are favor- 

 able to rust development is to be expected. This paper discusses the 

 present known distribution and relationships of the rust of timothy 

 and summarizes previous investigations of this disease in Europe and 

 America. New information on its physiological specialization and 

 methods of winter survival and on the resistance of timothy strains 

 and varieties to rust is also presented. 

 Respectfully, 



Wm. a. Taylor, 



Acting Chief of Bureau. 

 Hon. James Wilson, 



Secretary of Agriculture. 



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