. Diseases of economic plants. Plant diseases. 228 Diseases of Economic Plants blight is also serious on tomatoes in the South, on leaves and on fruits, where it produces a rot. It is found also upon eggplants. This is a disease characteristic of dry soils and seasons, and is likely to be associated and confounded with tip-burn. General spraying (p. 236) will hold this blight in check. Tip-burn. ^^^' ^-^ — Leaves die at the edges and tips, curl somewhat, and eventually the whole top withers. This condition occurs when the sun is hot and the winds dry, and is especially noticeable when a cool,
. Diseases of economic plants. Plant diseases. 228 Diseases of Economic Plants blight is also serious on tomatoes in the South, on leaves and on fruits, where it produces a rot. It is found also upon eggplants. This is a disease characteristic of dry soils and seasons, and is likely to be associated and confounded with tip-burn. General spraying (p. 236) will hold this blight in check. Tip-burn. ^^^' ^-^ — Leaves die at the edges and tips, curl somewhat, and eventually the whole top withers. This condition occurs when the sun is hot and the winds dry, and is especially noticeable when a cool, wet period is followed by hot, dry weather. It has been asserted that the primary cause is attack by leaf-hop- pers. Though not due to a parasite, spraying with Bor- deaux mixture lessens the loss. Wilt -^0' '^'^' ^21 (Fusarium oxysporu7n Schl. and Fusarium sps.). — This wilt is definitelj^ known in many states, and is probably identical with a very destructive potato disease of England, Germany, France, and Belgium. When the plants are about a foot high, or in mild cases a little later, the first trace of the wilt is noticeable. The leaves, which are usually light-colored, assume a dull, un- healthy appearance, with rolling or curling of the margins. Progressive disease gradually causes the top to fall, and gives a general effect of premature ripening. When the diseased plants are pulled up, the partially dead roots are found to be quite brittle, and frequently bear a white or pink mold. If the underground portion of the stem is cut across, a pronounced brown discoloration is visible. This brown stain is also found in the branches leading to the tubers, and a thin. Fig. 126.— Potato early-blight spots enlarged. After 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, 187
Size: 1437px × 1738px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1921
