THE WHEAT RUST . 201 



the winter and reproduce itself indefinitely, so that it is 

 probable that, in many cases, this stage of the fungus is 

 all that is necessary to explain its continued existence. 

 All farmers know with what marvelous rapidity 

 wheat rust spreads, if wet weather occurs shortly before 

 harvest. It is a disease for which, as yet, no successful 

 remedy has been found. Full knowledge of its life-his- 

 tory is yet wanting, and, possibly, when more is known, 

 successful preventives may be suggested. Early ripen- 

 ing varieties are less liable to damage than others. The 

 fungus often passes the summer on volunteer wheat, 

 hence this should be destroyed. A discussion of the 

 life-history of the European wheat rust may be found in 

 W. G. Smith's '* Diseases of Field and Garden Crops" 

 (pp. 147-207). The American rust is treated of in Bul- 

 letin No. 26, Indiana Experiment Station ; Bulletin No. 

 5, Minnesota Experiment Station ; and in various other 

 periodicals. 



