•286 CHAPTER XVII 



(2) For Seed. — Teff should be cut as soon as the seed is 

 mature ; if allowed to get over-ripe a good deal of it will be 

 lost through shattering. 



By sowing early the first crop can be used for hay, and 

 the aftermath for seed. 



Diseases and Pests. — Striga liitea and a leaf rust, 

 Uromyces tcffi (P. Evans) are found. The latter has not 

 proved serious. 



Striga lutea can be controlled in some parts by sowing in 

 •October and November, cutting the first crop of hay, which 

 will be before the parasite has seeded, allowing a fair growth 

 of aftermath, and ploughing down the whole. 



GRASS SORGHUMS (JOHNSON'S, SUDAN AND TUNIS 

 GRASSES). 



Sudan Grass (Andropogan sudanense). — This is a 

 summer annual hay grass rapidly becoming popular and of 

 increasing importance in South Africa. It was introduced into 

 South Africa in 1914 by the Department of Agriculture 

 (obtained from Khartuuin, Sudan, by the United States of 

 America in 1909). 



Description. — It is indigenous to Northern Africa, and is 

 believed by Piper to be the wild original form of the cultivated 

 sorghums, since it crosses spontaneously with the cultivated 

 sorghums. 



It is a tall, leafy grass, reaching a height of six to ten 

 feet, stools very freely, of quick growth, with comparatively 

 fine, erect stems and heavy yielding. It differs from Johnson's 

 grass in that it has no underground stems and is an annual. 



" The seed of Sudan grass is plumper and larger than 

 that of Johnson grass, and it breaks off from the branch with a 

 small portion of the rachis attached, whereas the seed of the 

 former grass is flatter and breaks off smoothly, with a well- 

 defined scar." 



Tunis Grass {A. sorghum var. virgatum) has seed with 

 more conspicuous awms, narrower seed, and shatters at maturity 

 while leaves are still green, whereas the seed of Sudan grass is 

 persistent after maturity. 



The hulls or glumes of Sudan grass are awned (may be 

 broken off in threshing) , and when in flower are often purplish 

 in colour, some fading to a yellow colour when the seed ripens. 



