122 DISEASES OF CROPS. 



blight is unknown, but only that portion which is called 

 the vegetative or " larval " condition of a fungus. This 

 fungus attacks the stems near the roots ; it seldom ex- 

 tends further than the third joint, and is frequently found 

 below the second. The " straw blight " (as far as is 

 known) simply consists of a ramifying mycelium, whose 

 hyphsB pass through the cell-walls of the host-plant, and 

 thereby greatly injure the infested plant. The fungus 

 often stops growth, and sometimes proves fatal to plant- 

 life. Infested crops are considerably reduced in quantity 

 as well as quality. Upon this point the following facts 

 may be recorded : — 



During the seasons of 1887 and 1888, the author grew 

 meadow hay upon a sandy loam which had previously 

 grown barley. Before laying down for grass, the soil 

 was well manured with farmyard manvire, and during the 

 early spring (1887) the grass was top-dressed with a 

 mixture containing 1 cwt. each of guano and sodium 

 nitrate, and 2 cwts. of superphosphate of lime per acre. 

 In May of the same year, the grass was top-dressed with 

 I cwt. of iron sulphate per acre. At the harvest (June, 

 1887), the crop yielded 2 tons 8 cwts. of hay per acre. In 

 the autumn of 1887 the same land was treated with 10 

 tons of farmyard manure per acre, and in the early spring 

 of 1888 received a top-dressing of the previously men- 

 tioned " mixed manure," minus the iron sulphate. As the 

 spring advanced, it was observed that nearly the whole of 

 the grass was, more or less, infested with the so-called 

 " straw blight." As it was interesting to compare the 

 yield, etc., of hay from the infested field with the previous 

 year's crop, only a very narrow strip of grass was top- 

 dressed with iron sulphate (| cwt. per acre) to observe 

 its effect upon the mildew. At the harvest (1888) the 



