258 CHAPTER XIV 



varieties, early varieties and early planting, should be resorted 

 to. 



Smut (Tilletia foetens). — Brand, Burnt or Stinking Smut 

 is of considerable economic importance and can be controlled 

 very easily, as already described. The durums are usually 

 very free from this disease. 



Loose Smut of Wheat {Ustilago tritici). — No practical 

 remedy. Jensen's hot water treatment, in which wheat is 

 steeped in water at 129° for ten minutes, may be employed 

 where facilities are available. A change of seed is also recom- 

 mended. 



Take-all, or Vrotpootje (Ophioholus graminis). — This 

 disease has proved serious in the south-west Cape. The best 

 remedial measure is to practise a rotation of crops. 



There are two aspects of this disease, " Take-all " and 

 " White heads." The condition called " take-all " occurs 

 at an early stage of the growth of the host, causing the latter 

 to become yellow, and often die before a culm is formed. 

 Infection occurs at the base of a plant, wdiich appears black- 

 ened. The condition of " white heads " occurs when the host 

 has attained full growth. The spikes are of normal size, but 

 the grain either remains undeveloped, or is very much 

 shrivelled. The spikes and straw^ appear to be bleached, or 

 prematurely ripened. The entire plant is found to be dry and 

 dead, and for two or three inches at the base of the culm is 

 blackened as if charred. 



Oats is apparently unaffected by this disease, hence it 

 serves as a good change crop. 



Wheat Aphis (Toxoptera graminum). — This insect occa- 

 sionally causes a great deal of damage. Pasturing may be of 

 assistance. The spread of this pest is generally controlled by 

 parasites. 



WHEAT REFERENCES: 



» " Botany of Crop Plants." — Robbins. 



^ Bulletin No. Ill, Pullman Washington. 



•■' Ohio Bulletin 24,3. 



■* Minnesota Bulletin 131. 



* "The Story of a Loaf of Bread. "—T. B. Wood. 



" Wheat and Its Cultivation." — Richardson. 

 ' " Nomenclature of Wheat in South Africa." — Union Dept. of Agric. 



Bulletin No. 1. 

 ' " Breeding of Crop Plants." — Hayes and Garber. 

 » " Wheat, Flour and Bread."— Ottawa Bulletin No. 97. 

 '• " The Wheat Plant."— Percival. 



