. Diseases of economic plants. Plant diseases. 322 Diseases of Economic Plants usually turn yellow and fall off. Spots upon the stems show the same general character as those upon the leaves. The lower leaves, and the leaves of older plants, are most subject to the leaf-spot. Plants late in the season, as of the second and third cuttings, suffer much more than earlier in the season. These crops, especially in a dry season, if allowed to stand a little too long before cutting may be badly spotted, and the loss in hay, through fallen leaves, may be. 12 3 4 Fig. 168. — Four alfalfa leaf-spots due
. Diseases of economic plants. Plant diseases. 322 Diseases of Economic Plants usually turn yellow and fall off. Spots upon the stems show the same general character as those upon the leaves. The lower leaves, and the leaves of older plants, are most subject to the leaf-spot. Plants late in the season, as of the second and third cuttings, suffer much more than earlier in the season. These crops, especially in a dry season, if allowed to stand a little too long before cutting may be badly spotted, and the loss in hay, through fallen leaves, may be. 12 3 4 Fig. 168. — Four alfalfa leaf-spots due to: 1, Ascochyta; 2, Pseudope- ziza; 3, Cercospora; 4, Stagonospora. After Stewart and others. considerable. The plants are never killed by this disease, though young fields which have not yet become well estab- lished may be ruined. Its mode of dissemination is unknown, and seed treatment is useless as a preventive. The only practicable treatment is to mow down badly diseased plants with the hope that the new shoots which spring forth may overcome the disease. If the disease appears just before cutting time, the mowing should be hastened a few days in order to avoid loss from leaf shedding. Yellow leaf-blotch ^'^^ {Pyrenopeziza medicaginis Fcl., Sporonema). — This disease is known from Vermont to the Pacific, in Europe and South America, and under certain. 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 Stevens, Frank Lincoln, 1871- [from old catalog]; Hall, John Galentine, 1870- [from old catalog] joint author. New York, The Macmillan company
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Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1921
