. Diseases of economic plants. Plant diseases. about 3-8 mm. in diameter, many or few according to the severity of the infection. In or near the centers of the older spots upon the upper surface of the leaves are seen the nearly microscopic pycnidia which are often arranged in concentric circles. On the young shoots the spots are some- what more reddish and are often cracked longitudinally, but otherwise they are as upon the leaves. ;§ This rot is much worse in warm, humid £ weather than in dry times, and a few days | of muggy weather may so favor the § growth of the causal fungus as to develo
. Diseases of economic plants. Plant diseases. about 3-8 mm. in diameter, many or few according to the severity of the infection. In or near the centers of the older spots upon the upper surface of the leaves are seen the nearly microscopic pycnidia which are often arranged in concentric circles. On the young shoots the spots are some- what more reddish and are often cracked longitudinally, but otherwise they are as upon the leaves. ;§ This rot is much worse in warm, humid £ weather than in dry times, and a few days | of muggy weather may so favor the § growth of the causal fungus as to develop % an epidemic, which may in turn be | checked by a dry spell. Often the dis- < ease appears in distinct waves during the season, each wave corresponding to a climatic condition favorable to infection and usually lagging behind such favor- able condition a period of 8 to 14 days, the time necessary after infection for the disease to become conspicuous enough to attract the attention of the vineyard- ist. The first infections of each season occur upon the stem, leaf, petioles, and tendrils. While the Scuppernong occasionally shows a few spots upon leaf or berry and the blossom is sometimes affected, this variety is practically 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- joint author. New York, The Macmillan Company
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Keywords: ., bookauthorstevensf, bookcentury1900, bookdecade1910, bookyear1910
