. Diseases of economic plants. Plant diseases. Pomaceous Fruits 37 badly affected fruits. Scabby fruits are much more sus- ceptible to storage rots than are clean fruits (p. 49). Upon the leaves and more rarely upon twigs the fungus forms a thick velvety coat, varying from dark olive-green to black, in spots at first circular in outline, later irregular and coalescing. The irritation and retardation of growth caused by the presence of the fungus often induces the leaves to curl and wrinkle in a characteristic manner. The fungus winters on fallen leaves, and wind-borne spores from them give ris
. Diseases of economic plants. Plant diseases. Pomaceous Fruits 37 badly affected fruits. Scabby fruits are much more sus- ceptible to storage rots than are clean fruits (p. 49). Upon the leaves and more rarely upon twigs the fungus forms a thick velvety coat, varying from dark olive-green to black, in spots at first circular in outline, later irregular and coalescing. The irritation and retardation of growth caused by the presence of the fungus often induces the leaves to curl and wrinkle in a characteristic manner. The fungus winters on fallen leaves, and wind-borne spores from them give rise to spring infection. Cf. pp. 58, 60. The injuries by this disease may be enumerated as fol- lows: lessened leaf value, retarded twig and wood growth, premature fall of fruit, retardation of full de- velopment of fruit, and injury to sale and keep- ing quality of fruit. Baldwin, Golden Rus- set, and Hubbardston are among the most re- sistant varieties, though scab-resistance seems to vary geographically and even seasonally. Cf. p. 60. Bordeaux mixture and lime-sulfur are effective sprays. It is especially important to apply the mixture immediately be- fore the blossoms open, again just after the petals fall, fol- lowed by one or two later sprayings. Cf. p. 57. Dusting is discussed on page 446. Burning of infected, fallen leaves is a good sanitary measure. Blotch ^^"^o- ^-1 {Phyllostida solitaria E. & E.). — In some sections of the country this disease of bark, leaf, and fruit is even more troublesome than any of the preceding, though its. Fig. 13. — Apple blotch, and Rorer. After Scott. 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- [from old catalog]; Hall, John Galentine, 1870- [from old catalog] joint author. New York, The Macmillan company
Size: 1530px × 1632px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1921
