. Citrus fruits;. Citrus fruit industry; Citrus fruit industry. 368 Citrus FrUits Leaf Gumming This is very common, especially on orange trees, in hot localities. Dark reddish colored, slightly raised spots or areas appear on the leaves in places where they have been turned up and the under side exposed to the sun or frost. These spots are formed by the secretion of a gum-like sub- stance in the tissue just under the epidermis and are simply the result of sunburn or frost injury at a time when the leaves are young and tender. The trouble is not serious and need not be Fig. 129. — Redd
. Citrus fruits;. Citrus fruit industry; Citrus fruit industry. 368 Citrus FrUits Leaf Gumming This is very common, especially on orange trees, in hot localities. Dark reddish colored, slightly raised spots or areas appear on the leaves in places where they have been turned up and the under side exposed to the sun or frost. These spots are formed by the secretion of a gum-like sub- stance in the tissue just under the epidermis and are simply the result of sunburn or frost injury at a time when the leaves are young and tender. The trouble is not serious and need not be Fig. 129. — Reddish gum areas on under side of leaf caused by sunburn. Gumming of Seed Bed Stock (Pythiacystis citrophthora) It often happens that the brown rot fungus, becoming established in the soil used for seed beds, will infect large numbers of sweet orange seedlings, especially where the soil is allowed to become too wet. Many of the seedlings are girdled at the surface of the ground and entirely ruined and have to be discarded when the plants are dug for sale. Sour orange plants are somewhat more resistant, but even they will sometimes show a considerable amount of gumming, as immunity to the brown rot fungus is not fully acquired until after the plants have been transferred to the nursery 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 Coit, John Eliot, 1880- [from old catalog]. New York, The Macmillan company
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1915
