FORAGE CROPS 



385 



brown. Each spot bears several light brown pycnidia 

 visible on both surfaces of the leaf. 



Dodder (Cuscuta). — Dodder, or love vine, is a parasitic 

 flowering plant. It consists of yellow, threadlike stems 

 which coil closely around the alfalfa stems, and take nour- 

 ishment from them. It reproduces by seed, and the seed 

 may readily pass with alfalfa seed unless very carefully in- 



1 2 3 



Fig. 164. — 1, Alfalfa seed ; 2, seed of large seeded dodder ; 

 3, seed of small seeded dodder, natural size. After Stew- 

 art and others. 



spected. The parasite is absolutely ruinous to the portions 

 of the field that are infected by it, and, since it spreads 

 rapidly, it is a very serious enemy. 



Badly infected fields should be plowed up. If fields are 

 infected in only a few spots, these spots may be dug over or 

 burned over before the dodder ripens its seed, using kero- 

 sene and straw to insure heat sufficient to kill every in- 

 fected plant, and a margin of a few feet entirely around the 

 infected spot. 



BLUEGRASS 



Rust (Pucdnia Poarum Niels). — The uredo of this 

 rust takes even greater prominence than does the uredo of 

 2c 



