Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . successful method of combat-ing it has been suggested. Corn rust is quite similar, in character and appear-ance, to the familiar red rust of wheat and oats. Itusually appears about midsummer, in the shape of small,brownish, dust-like blotches on the surface of the cornleaf. These dust-like patches, or pustules, consist ofthe summer spores of the fungus; the spores are of arich yellowish brown color, and are easily blown away bythe wind. Toward the end of su
Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . successful method of combat-ing it has been suggested. Corn rust is quite similar, in character and appear-ance, to the familiar red rust of wheat and oats. Itusually appears about midsummer, in the shape of small,brownish, dust-like blotches on the surface of the cornleaf. These dust-like patches, or pustules, consist ofthe summer spores of the fungus; the spores are of arich yellowish brown color, and are easily blown away bythe wind. Toward the end of summer these brownishspores are replaced by blackish ones, so that the pustulesthen assume a blackish appearance. These dark-colored 208 FUNGI AlfD FUXGICIDES spores are the winter sjDores, and are very different instructure and appearance from the summer spores. Thetwo kinds are produced from the same mycehum, and atcertain seasons they may be found intermingled in thesame mass, or pustule. This fungus usually only devel-opes after the corn has gotten well along in its growth,so that the effect of its injury is less than if the very. FIG. 86. CORN KUSt. a, Section of leaf showing teleuto-spores; h, uredo-spores; c, teleuto-spores. Magnified. young plants were attacked. Hence it seldom assumesa serious economic importance. The brown summer spores (called by botanists uiedo-spores) are nearly spherical, with the outer wall thicklystudded with minute pointed projections (Fig. 86 l).They are about one-one thousandth of an inch in diam-eter, and are borne on slender stalks arising from the THE BACTERIAL DISEASE OF CORX 209 mass of the mycelium, from which they readily serve to spread the disease during a limited timein summer, but ai-e supposed not to survive the blackish winter spores (called by botanists theteleuto-spores) are decidedly diiferent in structure andappearance from the others. A cross section of a cornleaf through one of the blackish pustules i
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
