. Diseases of economic plants. Plant diseases. Trees and Timber 389 surrounded by a border of dead tissue. Premature defolia- tion results. The disease is prevalent in all parts of the United States. FILBERT, HAZEL Blight '^'' (Bacteria). — A serious blight, which in many respects resembles blight of pear, affects the filbert in Oregon. It occurs on buds, shoots, leaves, and as cankers on larger limbs. Black-knot ^^^ {Cryptosporella anom- ala (Peck) Sacc.). —In 1892 Halsted noted black-knot as destructive to sev- eral hundred trees in New Jersey, and in 1893 Humphry described the same disease
. Diseases of economic plants. Plant diseases. Trees and Timber 389 surrounded by a border of dead tissue. Premature defolia- tion results. The disease is prevalent in all parts of the United States. FILBERT, HAZEL Blight '^'' (Bacteria). — A serious blight, which in many respects resembles blight of pear, affects the filbert in Oregon. It occurs on buds, shoots, leaves, and as cankers on larger limbs. Black-knot ^^^ {Cryptosporella anom- ala (Peck) Sacc.). —In 1892 Halsted noted black-knot as destructive to sev- eral hundred trees in New Jersey, and in 1893 Humphry described the same disease upon hazel canes in Massachu- setts. It is characterized by numer- ous small, elliptical, warty emergences upon the bark of the diseased branches. The diseased portions are sunken, owing to the contraction of the inner bark to a mere line. The girdling pro- duced results in death of the affected canes and general injury similar to that produced by plum knot. Affected branches should be cut and Fig. 206.— Elm leaf- spot. After Heald. HEMLOCK, WESTERN {Tsuga heter- ophijlla) Heart-rot ^^^ (Echinodontium tindo- rum E. & E.). — The fungus enters through wounds, chiefly branch stubs, and produces a stringy brown rot of the heartwood, which extends to all parts of the tree. A single sporophore of the fungus on the first 16-foot log of the tree trunk may be taken to indicate that the heartwood is unmarketable in both the first and second logs. The position of the largest sporophore usually indicates the region of greatest 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, 1871-1934; Hall, John Galentine, 1870-. New York, Macmillan
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Keywords: ., bookauthorstevensf, bookcentury1900, bookdecade1920, bookyear1921
