FORAGE CROPS 



389 



in the early spring, upon many other varieties ; but the 

 uredo stage soon gains the ascendancy over it. All three 

 forms may be produced side by side, to some extent, 

 throughout the summer. 



Hibernation probably occurs in two ways, by the teleu- 

 tospores and by the mycelium, 

 which may remain alive in the 

 affected parts over winter. 



Anthracnose (Colletotrichum 

 Trifolii Bain). — This anthrac- 

 nose is now loiown in Ten- 

 nessee, Ohio, West Virginia, 

 Arkansas, Kentucky, and Dela- 

 ware. It is first found chiefly 

 upon the leaf stalks, later upon 

 the stems, near the surface of 

 the ground and just below the 

 flower clusters, as elongated 

 sunken spots, which result 

 eventually in the death of the 

 whole plant. It frequently 

 causes great loss, and is said 

 by Bain to be the most serious 

 plant disease in Tennessee. 

 The same disease occurs upon 

 alfalfa, but alsike clover is nearly immune. The greatest 

 hope lies in the breeding of resistant varieties. 



Anthracnose (Gloeosporium caulivorum Kirchner). — 

 Long, brown to black, sunken spots upon stems and petioles, 

 causing death of the more distal parts, are diagnostic 

 characters of this anthracnose, which was first reported in 



Fig. 167. — Anthracnose on red 

 clover stem and petiole. After 

 Jackson. 



