A Study of Meadow-Crop Diseases in New York 



33 



TABLE 13. 



Effect of Sulfur on Urediniospore Germination of Uromyces Trifolii 

 Hybridi 



TABLE 14. Effect of Sulfur on Urediniospore Germination of Uromyces Trifolii 



Fallens 



The effects of the various sulfurs on the spores are illustrated in figure 6. 

 These drawings, in conjunction with the rather low germinations obtained, 

 indicate that sulfur offers promise for field work in controlling the clover 

 rusts. The reduction in germination caused by any of the dusts is far 

 from complete, yet the tubes are so short and abnormal that many of 

 them would probably never get into the stomates. Another interesting 

 fact brought out by tables 13 and 14 is that the sulfurs reduced the germina- 

 tion more in 1928 (experiments 5 to 8) than in 1927 (experiments 2 to 4). 

 This may be due to the expression of the influence of seasonal differences 

 on the sensitiveness of the urediniospores. 



Effect of copper. Copper-lime dust was not tested against the germina- 

 tion of the urediniospores except in 1928. It would be interesting to have 

 data from 1927 to see if the sensitiveness of the spores to this fungicide 



