. Diseases of economic plants. Plant diseases. 108 DISEASES OF ECONOMIC PLANTS the buds are unfolding, first using an 8-10-50 mixture; second a 5-7-50 mixture. Leaf spot (Mycosphcerella sentina Desm.). —• The leaf spot, while rarely completely destruc- tive to foliage or crop, does interfere with the general pro- ductiveness and health of the tree by diminishing its green surface and sometimes by caus- ing defoliation. It is known over a wide range. The leaf spot may be distin- guished from the scab and the blight by the fact that the dis- eased area is rather sharply defined and characteristi
. Diseases of economic plants. Plant diseases. 108 DISEASES OF ECONOMIC PLANTS the buds are unfolding, first using an 8-10-50 mixture; second a 5-7-50 mixture. Leaf spot (Mycosphcerella sentina Desm.). —• The leaf spot, while rarely completely destruc- tive to foliage or crop, does interfere with the general pro- ductiveness and health of the tree by diminishing its green surface and sometimes by caus- ing defoliation. It is known over a wide range. The leaf spot may be distin- guished from the scab and the blight by the fact that the dis- eased area is rather sharply defined and characteristically angular in outline. The center of the spot, usually ashen in color, is surrounded by a narrow brown zone, and this in turn by one of purplish hue. The ashen center bears several very mi- nute dark-colored pycnidia. The treatment recommended for pear scab is effective in pre- venting this disease. Leaf blight {Fahroea maculata (Lev.) Atk.).—This leaf blight is almost as widely distributed as is the pear itself, though less abundant in the South and West than in the North and East. Its spot does not exhibit the striking zonal arrangement described for the leaf spot (septoriose),. Fig. 45. — Pear leaf spot (septo riose). 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, 1871-1934; Hall, John Galentine, 1870-. New York, Macmillan
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Keywords: ., bookauthorstevensf, bookcentury1900, bookdecade1910, bookyear1910
