. A manual of veterinary hygiene. Veterinary hygiene. FOOD 163 The grain in course of time gets converted into a black or olive-coloured greasy powder, of a fishy objectionable odour. Smut (Fig. 26) is a disease which attacks the flowering heads of grasses and grains, more particularly, wheat, bar- ley, oats, and rye. It com- mences as a white deposit, but later turns to a black mass. This consists of spores of the fungus Ustilago carbo. The effect of this fungus is to completely destroy the flower- ing head, so that the whole ear disappears and nothing but its framework is left. The disease i
. A manual of veterinary hygiene. Veterinary hygiene. FOOD 163 The grain in course of time gets converted into a black or olive-coloured greasy powder, of a fishy objectionable odour. Smut (Fig. 26) is a disease which attacks the flowering heads of grasses and grains, more particularly, wheat, bar- ley, oats, and rye. It com- mences as a white deposit, but later turns to a black mass. This consists of spores of the fungus Ustilago carbo. The effect of this fungus is to completely destroy the flower- ing head, so that the whole ear disappears and nothing but its framework is left. The disease is very readily de- tected, and unlike Bunt it has no odour. Rust and Mildew are pro- duced by different stages of the same parasite, known as Puccinia graminis (Fig. 27). It affects all grasses and cereals, and is an extremely serious disease from an agri- cultural point of view. The life history of the para- site is complex and interest- ing, it requires to pass through two different host plants in order to complete the cycle of its existence, and in each host it produces a distinct disease; in fact, its behaviour is more like that of an animal parasite. The stems and leaves of all grasses and cereals are liable to be attacked in the early summer by yellowish-red lines * ' Elements of Agriculture.' 11—2. Fig. 26.—Smut of Oats (Fream).* A, panicle of oats attacked from below upwards; B, spikelet with the fungus in an early stage of growth ; C, free spores of Ustilago carho ; D, spores germinating and producing yeast-like buds. Digitized by Microsoft®. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Smith, Frederick 1857-1929. New York : W. R. Jenkins
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