A Study of Meadow-Crop Diseases in New York 2? 



CLOVER RUSTS 



All the rusts of the common clovers are included under the heading 

 Clover rusts because of their close relationship. This has been deemed 

 necessary since much confusion in their nomenclature exists through 

 failure to distinguish between the fungi on the various clovers. Emphasis 

 is placed on the rust of red clover, and the points of difference between it 

 and the others are emphasized where necessary. 



Suscepts 



Arthur (1912:255) regards the rust on red clover as identical with that 

 on crimson clover and on zigzag clover (Trifolium medium). He believes 

 also that the rusts on alsike and white clover are identical but are different 

 from that on red clover. The fungus on alsike and white clover also 

 attacks the following plants, according to Arthur: Trifolium amabile 

 H. B. K., Trifolium amphianthum T. & G., Trifolium incarnatum L., 

 and Trifolium logani House. He believes that crimson clover harbors 

 both rusts. Davis (1924 a), however, has separated the alsike rust as a 

 distinct disease. 



A perusal of the literature reveals only two references to varietal sus- 

 ceptibility. A meager report by Mains from Indiana states that Italian 

 red clover is resistant (Stakman, 1922:243). An anonymous contributor 

 (1923) from the same State says that " two hundred seven selections 

 were made from a large number of plants studied which showed a high 

 resistance or immunity to rust, many of these being resistant to mildew." 



The disease 



Writers, almost without exception, have referred to these diseases as 

 clover rust. Freeman (1905:292) speaks of them as clover leaf rust, but 

 since many other parts of the plants besides leaves are attacked, this 

 name is hardly satisfactory. Since each of the three pathogenes are 

 definitely restricted to certain clovers (Davis, 1917), it seems best to 

 combine the common name of the suscept with the term rust, to distinguish 

 the three diseases. They therefore are called red-clover rust, alsike rust, 

 and white-clover rust, respectively. 



History and range 



Red clover probably is rusted wherever it is grown, for it has been 

 reported from 33 States, from 5 Canadian provinces, from 17 countries 

 of Europe, from Asia (Sydow and Sydow, 1910:131-134), and from 

 Australia (McAlpine, 1901): 42-44). Although the rusts of alsike and white 

 clover have not been reported as frequently as has that of red clover, they 

 apparently arc as nearly ubiquitous. 



