204 



places in Jefferson County, the rust in its uredinial stage was abundant 

 this year. The rainy season in the southern part of the State favored the 

 development of the fungus. 



At LaFayette, on the Experiment Station farm, the uredinial stage of 

 the rust is abundant in a timothy meadow, which was sown down this 

 spring. The rust is most abundant in the low parts of the meadow, and 

 even as late as at this writing (Nov. 22nd^) the rust sori are abundant on 

 the green blades. 



The vitality of the urediniospores, collected at LaFayette, Ind., Nov. 

 22nd, 1910, was tested by means of hanging drops in Van Tiegham cells. 

 Spores were taken both from the green blades and from those that had 

 been killed by the frost. While the former showed much the more vigor- 

 ous germination, the vitality of the spores in both cases proved to be high. 

 I'his shows that they have withstood the cold weather, thus far, very well, 

 and points to the probability that the rust may be able to pass the winter 

 here in the uredinial stage, as it is thought to do in Europe. 



From the above conditions it seems evident that timothy rust is in 

 North America to stay, and its abundance will doubtless vary with the 

 varying conditions that favor or check its development. Some of the 

 conditions that seem to favor the development of the fungus are a heavy, 

 luxuriant growth of the host on ground that tends to hold moisture, along 

 with rainy weather with cool nights and moderately still, warm, but not 

 hot, days. Obviously, the opposite set of conditions tend to be unfavor- 

 able for the greatest development of the rust. 



While the best possible attention to both air and soil drainage will no 

 doubt lessen the attacks of the disease to some extent, yet its ultimate 

 control doubtless lies in the field of the plant breeder. The production 

 of a strain of timothy having a high resistance to rust, as well as having 

 at the same time the best forage qualities, would be of vast importance. 



Purdue University Agricultural Experiment Station, Lafayette, Ind. 



^18 F. is the minimum thus far (Nov. 22d) at Lafayette, according to the 

 official reading of the U. S. Weather Bureau at this station. 



