GRAMINEOUS CROPS. 83 



Prevention. — Sow oaly new and sound barley. 



Citre. — (1) Steep the seed, for two or three hours before 

 sowing, in a solution of iron sulphate (1 to 2 per cent, 

 solution). (2) Copper sulphate is recommended for " pick- 

 ling" the seeds of various cereals before drilling; but 

 this substance often destroys the germinating power of 

 seeds (vide Biedermann's Centralblatt fUr Agricultur- 

 Chemie, 1886, p. 766). 



The Smut of Barley {Ustilago carbo) and other 

 cereals will be described under " The Parasites of Oats." 



(2) The Parasites of Buckwheat {Polygonum 

 fagopyrum). ^ 



According to Alphonse De CandoUe, buckwheat is pro- 

 bably an Asiatic plant. " In China the seed is used for 

 making bread, and in Europe it. is employed for various 

 culinary purposes.'' In England it is principally sown to 

 produce a covert and food for game. On the Continent 

 (and also to a minor extent in England) buckwheat is used 

 as a green manure.. The gaseous prodacts of its decom- 

 position destroy various injurious insects. 



The Buckwheat Eelworm {Tylenchiis Haven- 

 xteinii) belongs to the same genus as the clover eelworm, 

 already described. It is a nematoid, and measures 

 1-43 mm. x O'OSOl mm.^ These thread-worms attack the 

 roots and stems of the host-plant. 



Cure. — ^Drs. Kiihn and Oehmichen recommend liberal 

 manuring, especially with kainit. 



The Buckwheat Beetle (Phyllopertha horticola) 



' Buckwheat belongs to the Polygonacete (dock and sorrel order). 

 It is not a gramineous crop, although described under that heading. 

 = 1 millimetre (mm.) = 0-03937 inch. 



