. Diseases of economic plants. Plant diseases. Vegetable and Field Crops 197 ing originally often $1000 per acre — and thus destroy their value for lettuce culture. The damage is thus much more than injury wrought merely to the current crop. The sclerotia, when favorably situated, are capable of germination, each producing several trumpet-shaped organs (Fig. 106), with stems about 15 mm. long and disks 3-8 mm. or less in diameter. Spores, capable of initiating the fungous growth upon dead or sick lettuce tissue, issue in great num- bers from these disks, and from material thus infested the fun
. Diseases of economic plants. Plant diseases. Vegetable and Field Crops 197 ing originally often $1000 per acre — and thus destroy their value for lettuce culture. The damage is thus much more than injury wrought merely to the current crop. The sclerotia, when favorably situated, are capable of germination, each producing several trumpet-shaped organs (Fig. 106), with stems about 15 mm. long and disks 3-8 mm. or less in diameter. Spores, capable of initiating the fungous growth upon dead or sick lettuce tissue, issue in great num- bers from these disks, and from material thus infested the fungus can make its way into the healthy lettuce Fig. 106. — Sderotia of Sclerotinia from lettuce germinating. If all infected plants be pulled and burned as soon as the first indication of disease is observed, the formation of sclerotia will be prevented. As an additional precaution it is well to spray the areas occupied by diseased plants thoroughly with Bordeaux mixture or bluestone solution. A few years of such procedure will much reduce the in- fection or perhaps eliminate it entirely. All lettuce trash should be removed from the beds, since it serves as the ini- tial point of attack for the fungus. Growers whose land is free from the disease should guartl against its introduction. 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, bookdecade1920, bookyear1921
