. California plant diseases. Plant diseases. Bulletin 218] CALIFORNIA PLANT DISEASES. 1175 All severe cuts or wounds should be carefully covered with grafting wax to allow healing over without decay. In top-grafting walnut trees this should be given special attention or serious decay may follow. Sun Burn. Figure 98. Serious damage is sometimes caused from this source, both on the fruit and the tree. In the latter case the trunk is usually affected, dead areas developing in the bark on the sunny side. This originates mostly in winter when the nights are cold and the days bright and sunny. Not u
. California plant diseases. Plant diseases. Bulletin 218] CALIFORNIA PLANT DISEASES. 1175 All severe cuts or wounds should be carefully covered with grafting wax to allow healing over without decay. In top-grafting walnut trees this should be given special attention or serious decay may follow. Sun Burn. Figure 98. Serious damage is sometimes caused from this source, both on the fruit and the tree. In the latter case the trunk is usually affected, dead areas developing in the bark on the sunny side. This originates mostly in winter when the nights are cold and the days bright and sunny. Not usually serious on thrifty trees growing in good soil. Black walnut. Fig. 98.—Walnuts affected by sun burn. trunks with rough bark are not affected by sun burn, so that trees grafted high on such trunks are immune. On the fruit the sun sometimes has a disastrous effect, causing a blackening and burning of the husk on one side during extremely hot weather in summer. The meat is also blackened, and the husk sticks to the shell so that separation is difficult and a black spot is left. Thrifty trees are less affected, particularly when supplied with an abundance of moisture at the root. Individual trees or varieties vary in suscepti- bility to this trouble, and this quality should be considered in planting in localities where trouble from sunburn is likely to occur. Perforation. Figure 99. The shell fails to develop properly, being only partially formed, with numerous openings and thin places. This appears to be simply a lack of development due to climatic conditions and occurs in seasons with a dry spring and a dry, hot summer. Seems worse on trees attacked by 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 Smith, Ralph E. (Ralph Eliot), 1874-1953; Smith, Elizabeth H. (Elizabeth Hight), 1877-1933. Berk
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectplantdi, bookyear1911
