A Study of Meadow-Crop Diseases in New York 



35 



The effect of the copper on the germination is illustrated also in figure 6- 

 A comparison of this figure and the data presented in table 15 with the 

 data in tables 13 and 14 on the effect of sulfur shows that sulfur is more 

 likely to control the disease in the field than is the copper- lime dust. 



Effect of lime. A few tests were conducted to see what effect lime alone 

 would have in reducing the germination of the urediniospores. The 

 results are presented in table 16. 



TABLE 16. 



Effect of Lime on Urediniospore Germination of Uromyces Trifolii 

 Hybridi and Uromyces Trifolii Fallens 



When these results are compared with the checks, given in table 15, 

 it appears that lime is not toxic to Uromyces trifolii fallens and only 

 slightly so, if at all, to Uromyces trifolii hybridi. 



PSEUDOPEZIZA LEAF SPOT 



Suscepts 



Many of the species of Trifolium have been listed by Jones (1919:5) 

 as suscepts of Pseudopeziza leaf spot. The writer has collected good 

 material on Trifolium pratense, T. hybridum, T. repens, and T. medium, 

 and the first three species have been inoculated successfully with a pure 

 culture isolated from T. pratense. Inoculations upon Melilotus alba, 

 Medicago sativa, and Vicia villosa with the same culture were unsuccessful. 



Williams (1927) reports that early varieties of red clover suffer more 

 from this disease than do the later-maturing varieties. The less-suscep- 

 tible ones are Vale of Clwyd (medium-early strain), American medium, 

 and Bohemian. Italian, French, Swiss, and Silesian varieties he found to 

 be the most susceptible. 



The disease 



This disease is usually referred to merely as leaf spot. Since it should 

 be distinguished in some manner from the other leaf spots, the name 

 Pseudopeziza leaf spot is used here. 



History and range 



According to the supplements of the Plaid Disease Reporter (his malady 

 occurs from Vermont to California, and from New Brunswick, Canada, 

 south to Virginia and Tennessee. It is found in practically every clover 



