. Diseases of economic plants. Plant diseases. Ornamental Plants 419 loss occasioned by the diminution in vigor of the plant and consequent imperfection of bloom is large. The sori, 2-3 mm. in diameter, which are diagnostic, first appear as small blisters covered by the epidermis. The rupture of this covering dis- closes a dark brown mass of spores. The sori are usually numerous upon the lower leaf surface, and the spores form dusty coatings upon the leaves. Badly affected leaves curl; shrivel, and die. The plants are dwarfed and fail to produce flowers of value. All new stock introduced to th
. Diseases of economic plants. Plant diseases. Ornamental Plants 419 loss occasioned by the diminution in vigor of the plant and consequent imperfection of bloom is large. The sori, 2-3 mm. in diameter, which are diagnostic, first appear as small blisters covered by the epidermis. The rupture of this covering dis- closes a dark brown mass of spores. The sori are usually numerous upon the lower leaf surface, and the spores form dusty coatings upon the leaves. Badly affected leaves curl; shrivel, and die. The plants are dwarfed and fail to produce flowers of value. All new stock introduced to the houses should be care- fully inspected and all dis- eased stock destroyed by fire. New stock should be isolated and watched for a month or more to be sure that no rust develops. If disease ap- pears, all affected leaves should be picked and burned with precautions to avoid scattering the spores. If the rust continues to appear, all parts above ground must be destroyed by fire at the end of the season, and plants for the next year raised in un- contaminated soil and house. Ray-blight"*^'' {Ascochyta chrysanthemi Stev.). — In this disease, described by Stevens as doing considerable damage in North Carolina, the ray flowers are blighted, resulting in imperfect opening of the buds. Thorough spraying with Bordeaux mixture from the beginning of the season until. Fig. 219. — Chrysanthemum blossom distorted with ray- blight. 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
