. Manual of fruit diseases . Fruit. 348 MANUAL OF FRUIT DISEASES l)een the subject of horticultural writings and discussions for many years. Very recently it was found on pears in Australia. As already indicated, the disease is found more commonly in nurseries than in orchards, yet the latter are not exempt from attacks of the leaf-blight pathogene. In the nursery the trouble affects the leaves and twigs of seedlings; in the orchard, the fruits (Fig. 98), in addition, are susceptible. It appears that all varieties show the disease, yet the KiefFer and Angouleme are more resistant than the Seck
. Manual of fruit diseases . Fruit. 348 MANUAL OF FRUIT DISEASES l)een the subject of horticultural writings and discussions for many years. Very recently it was found on pears in Australia. As already indicated, the disease is found more commonly in nurseries than in orchards, yet the latter are not exempt from attacks of the leaf-blight pathogene. In the nursery the trouble affects the leaves and twigs of seedlings; in the orchard, the fruits (Fig. 98), in addition, are susceptible. It appears that all varieties show the disease, yet the KiefFer and Angouleme are more resistant than the Seckel, Wilder Early and Sheldon. It has also been ob- served that the Flemish, Lawrence, Bosc and Clapp Favorite are resistant. Symptoms. The disease makes its appear- ance early in the spring soon after the leaves develop. There develops a small circular, carmine- red spot, first on the upper, and then penetrating to the lower, sur- face. The color soon changes from red to dark-brown, with a slightly elevated, minute black spot in the center. If the lesions are numer- ous, they may merge, and thus the tissue between them turns brown. Affected young leaves shrivel; older ones change only in color. Badly diseased leaves turn yellow and fall prematurely. The fruit shows the same carmine-red spot which afterward assumes a darker color (Fig. 98). The skin is roughened, and the growth of the epidermis is hindered, causing a deep crack in the Fig 98. — Leaf-blight lesions 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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