. The principles of plant culture; a text for beginners in agriculture and horticulture. Gardening; Botany. VEGETABLE PARASITES AND WEEDS 179 the disease and be so thorough as to cover all susceptible parts, else it cannot be fully effective. Such thorough spraying requires a spray pump of high pressure provided with a fine nozzle. Some of the common diseases preventable by proper spraying are: scab of apple {Venturia maequalis) and pear (Venturia pyrina), downy mildew (Plasmopara mticola) and black-rot {Guignardia hidwellii) of grape, early blight (Alternaria solani) and late blight (PhytopMh
. The principles of plant culture; a text for beginners in agriculture and horticulture. Gardening; Botany. VEGETABLE PARASITES AND WEEDS 179 the disease and be so thorough as to cover all susceptible parts, else it cannot be fully effective. Such thorough spraying requires a spray pump of high pressure provided with a fine nozzle. Some of the common diseases preventable by proper spraying are: scab of apple {Venturia maequalis) and pear (Venturia pyrina), downy mildew (Plasmopara mticola) and black-rot {Guignardia hidwellii) of grape, early blight (Alternaria solani) and late blight (PhytopMhora in- festans) of potato, brown-rot {Sclerotinia frudlgena) and leaf-curl (Exoascus deformans) of the peach and the shot- hole disease (Cylindrospormm padi) of the cherry. The ap- ^^^^ff% g^ ^' '^-'i pie-scab as it appears on leaves M^.;,;::i:*'^»' ^mil is shown in Fig. 86; as it ap- pears on fruit in Fig. 81. A section through a scabby spot, magnified, is represented in Fig. 82. „-- _ ... _,, Fig. 81. — Scab on the apple. 329. Fungicides. —The most important fungicides in common use contain some form of copper or sulfur, although there are numerous other com- pounds having fungicidal properties. The practical value of a fungicide depends upon its ability to destroy the fungus without serious harm to the host, coupled with convenience of preparation or use, adhesiveness and cheap- ness. The copper compound best meeting these standards is bordeaux mixture; and lime-sulfur is the best sulfur compound. In general, the bordeaux mixture has greater fungicidal value but the lime-sulfur has replaced it for certain uses, partly because it has also value for control- ling certain insects (295).. 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 Goff, E. S. (Emmett Stull), 1852-1902; Moore, J. G. (James Garfiel
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