Forage Crops 



341 



nial in its perennial host, and smutted plants bear smut, 

 year after year. 



TIMOTHY (Phleum) 



Smut ^^^ (Ustilayo stricefornus (West.) Niessl). — This smut 

 occurs chiefly upon the leaves, more rarely upon other parts 

 of timothy, as well as 

 upon many species of 

 Agrostis, Poa, Elymus, 

 Bromus, Dactylis, Fes- 

 tuca, in Europe, Australia, 

 and generally throughout 

 the United States. The 

 spore masses form long 

 black lines upon the leaf, 

 and by merging and rup- 

 turing reduce the leaf to 

 a torn, blackened state. 

 The affected plants are 

 small, weak, and often fail 

 to make seed and the hay 

 value is thus lowered. 

 The disease is perennial 

 within the host. Infec- 

 tion takes place in the 

 blossom, resulting in a 

 seed bearing the myce- 

 lium of the smut. Hot- 

 water treatment of seed 

 (cold water 6 hours, 52° 

 C. (123° F.) 15 minutes) 

 gives promise of success. 



Rust ^^^ (Puccinia grani- 



inis phleipratensis) . — „ ,„ o • /-tt.-, 



rp,- . • 1 Fig. 182. — Son of Ustilago strisefor- 



This rust m general re- „,i, j^ leaves of timothy. After 



sembles the black-rust of Osner. 



