. Manual of tree diseases . Trees. MAPLE DISEASES 229 fungus. The spores from these structiu'es are disseminated by the rain. It is to be expected that perithecia with ascospores are formed in the leaves on the ground during the winter. The twigs have not been found affected. This disease is similar to the leaf- and twig-blight of sycamores described on page 333. The control measures are the same for both of these diseases. Canker Caused by Nectria cinnabarina Fries Maples are commonly affected by this canker. Other deciduous trees may also be attacked by this disease but it never assumes grea
. Manual of tree diseases . Trees. MAPLE DISEASES 229 fungus. The spores from these structiu'es are disseminated by the rain. It is to be expected that perithecia with ascospores are formed in the leaves on the ground during the winter. The twigs have not been found affected. This disease is similar to the leaf- and twig-blight of sycamores described on page 333. The control measures are the same for both of these diseases. Canker Caused by Nectria cinnabarina Fries Maples are commonly affected by this canker. Other deciduous trees may also be attacked by this disease but it never assumes great impor- tance owing to the causal fungus being only weakly parasitic. Twigs, small branches and young trees may be killed by the girdling action of the fungus. Symptoms. Small depressed dead areas of bark around wounds or branch stubs are the first evidences of the developing canker (Fig. 40). Flesh-colored or pink hemispherical bodies are pro- duced on the dead bark. Later the same pustules become chocolate-brown. If the fungus continues to spread, rolls of callus are formed around the affected area each year, until an open canker is produced which may girdle the limb. The mycelium grows most luxuriantly in the sapwood, causing a dark greenish discoloration (Fig. 41). The bark adjacent to the. Fig. 40. — Nectria canker 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 Rankin, W. Howard (William Howard), b. 1888. New York : The Macmillan Company
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1918
