. Manual of fruit diseases . Fruit. APPLE DISEASES 141 Symptoms. The first indication of the disease may appear while the fruit still hangs on the tree, and the symptoms consist in the develop- ment of a smooth, brownish discoloration in the skin. The rotted area increases in size, the general form being retained. The pathogene often comes to the surface and shows itself as grayish tufts (Fig. 37); these may be arranged in concentric circles. The rotting of the fruit is finally com- plete (Fig. 37). In many cases the affected fruit becomes jet black and the skin assumes an ebony aspect. Fruits
. Manual of fruit diseases . Fruit. APPLE DISEASES 141 Symptoms. The first indication of the disease may appear while the fruit still hangs on the tree, and the symptoms consist in the develop- ment of a smooth, brownish discoloration in the skin. The rotted area increases in size, the general form being retained. The pathogene often comes to the surface and shows itself as grayish tufts (Fig. 37); these may be arranged in concentric circles. The rotting of the fruit is finally com- plete (Fig. 37). In many cases the affected fruit becomes jet black and the skin assumes an ebony aspect. Fruits showing such symptoms usually exliibit no ex- ternal signs of fruiting bodies of the causal pathogene. The con- ditions that determine whether an apple affected with the brown-rot dis- ease will remain brown or will become black, as already described, are not well understood. The appearance of these various characters has been explained in relation to weather conditions as follows: — (a) if the weather is warm, and the atmosphere has a high relative humidity, the affected fruits become brown, and grayish tufts make an early ap- pearance ; (b) if the relative humidity is reduced, the fruit is at first brown, then black, and the tufts are rare or absent; (c) if the air is dry and cool, the affected fruit is black and no grayish tufts develop. In regions where dry air prevails, this type of the brown-rot disease is the more common. Likewise. Fig. 37. — Brown-rot on 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 Hesler, L. R. (Lexemuel Ray); Whetzel, Herbert Hice, 1877-1944. New York : Macmillan
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