. Diseases of economic plants. Plant diseases. Pomaceous Fruits 53 gummy exudate is usually present around the base of the tree and black rhizomorphs adhere to the roots. In late stages clusters of the gill-bearing sporophores (Fig. 25) develop; Armillaria mellea Vahl. Quantities of black, stringy, hard, shiny strands 1 to 2 mm. in diameter occur around the roots and in the adjacent soil. The gilled sporophores appear later (p. 370); Fomes annosus (Fr.) Cke. The sporophores are pore-bearing (p. 371); Septobasidium sps. with smooth pore-bearing surfaces; Ozonimn om~ nivorum, Sh. See Texas root-


. Diseases of economic plants. Plant diseases. Pomaceous Fruits 53 gummy exudate is usually present around the base of the tree and black rhizomorphs adhere to the roots. In late stages clusters of the gill-bearing sporophores (Fig. 25) develop; Armillaria mellea Vahl. Quantities of black, stringy, hard, shiny strands 1 to 2 mm. in diameter occur around the roots and in the adjacent soil. The gilled sporophores appear later (p. 370); Fomes annosus (Fr.) Cke. The sporophores are pore-bearing (p. 371); Septobasidium sps. with smooth pore-bearing surfaces; Ozonimn om~ nivorum, Sh. See Texas root-rot (p. 23); Xyl- aria sps.^^ The affected roots are covered with a thin, compact growth of mycelium, white at first, later developing into a black incrusta- tion. Minute, thread- like rhizomorphs ra- ^^V^^--Br«wn-rot produced by inocu- '^ . lation. JNote the lungus lorms the let- diate several centmie- ters A. M. C. Original, ters along the root. Affected roots are soon girdled and the distal parts die. Root-rot, due to one or another of these causes, is of wide and common occurrence, and results in large loss. It is found more frequently on newly cleared land than elsewhere. When the disease has advanced far enough to be recognized, no cure is available, and it is unsafe to replant in the infested place. Wood bearing root-rot fungi should be burned to lessen infection. Wood-rot '^'' of orchard trees is of the general character dis- cussed under Decay in live trees on page 354. It is a very important source of loss on fruit trees of all kinds, about one-half of all bearing trees being infected. The rot may chiefly be avoided by preventing wounds or by treating them with disinfectants. See p. 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-


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Keywords: ., bookauthorstevensf, bookcentury1900, bookdecade1920, bookyear1921