. Les maladies des plantes d'importance économique. Les maladies des plantes. Les fruits tropicaux 143 sont d'abord jaunâtres, l)ut comme la maladie avance ils deviennent presque noirs, antl enfin ouvrir. Le carbonate de cuivre ammoniacal ou la bouillie bordelaise permet d'éviter la tavelure. L'anthracnose, {CoUetotrichum s'étiolent-tip glaeosporioides Penz.). - Dans cette maladie les taches foliaires sont circulaires en ligne-, de couleur jaune, et porter le petit rectangle en filaments et spores de champignon causal. Les rameaux terminaux perdent leurs feuilles et mourir. La maladie a également lieu lors de la fruit de divers arbres d'agrumes. Rolf a fait état de son attaque sur le citron, où je

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. Diseases of economic plants. Plant diseases. Tropical Fruits 143 are at first yellowish, l)ut as the disease advances they become almost black, antl finally crack open. Ammoniacal copper carbonate or Bordeaux mixture will prevent scab. Anthracnose, wither-tip {CoUetotrichum glaeosporioides Penz.). — In this disease the leaf spots are circular in out- line, yellowish in color, and bear the small dark filaments and spores of the causal fungus. Terminal twigs shed their leaves and die. The disease also occurs upon the fruit of various citrus trees. Rolfs noted its attack upon the lemon, where it caused the fruit to fall prematurely, and Hume reports that it may occur upon the pomelo either before or after the fruit is picked. The brownish spots enlarge with age and become dirty black in color. The fun- gus invades the interior of the fruit as well as the rind. In all cases the diseased parts should be cut out, care being taken to cut far enough back to remove all injured parts; also affected fruits should be removed and destroyed. Spray- ing with Bordeaux mixture controls the disease upon the fruit. Root-rot (Phijtophthora terrestria Sherb.). — The first symp- toms are abundant exudations of gum upon the trunk of the tree; at the same time the bark develops brownish patches, which are thrown off, followed ])y other patches. The tree appears to lack nutrition, the leaves becoming yellow, scanty, and small. Though the trees heav considerable fruit, the amount of damage in Florida was estunated in 1896 to be. Fig. 75. — Orange leaves showing spots caused by anthracnose. Af- ter Hume.. 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 work.. Stevens, Frank Lincoln, 1871-1934; Hall, John Galentine, 1870-. New York, Macmillan

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