. Diseases of economic plants. Plant diseases. 70 DISEASES OF ECONOMIC PLANTS circular, rotten spot. This spot under favorable conditions rapidly increases in diameter, the rate varying from 1-10 mm. each day. The spots may be either single upon the fruit or very numerous, depending upon the abundance of the infecting spores. When a spot becomes quite large, it is usually somewhat depressed, with a shriveled, wrinkled surface, due to loss of turgor of the under- lying tissue caused by evaporation. As the spot ages minute spor- ing pustules of the causal fungus, barely visible to the naked eye,
. Diseases of economic plants. Plant diseases. 70 DISEASES OF ECONOMIC PLANTS circular, rotten spot. This spot under favorable conditions rapidly increases in diameter, the rate varying from 1-10 mm. each day. The spots may be either single upon the fruit or very numerous, depending upon the abundance of the infecting spores. When a spot becomes quite large, it is usually somewhat depressed, with a shriveled, wrinkled surface, due to loss of turgor of the under- lying tissue caused by evaporation. As the spot ages minute spor- ing pustules of the causal fungus, barely visible to the naked eye, appear, first at or near to its center. The tissue of the fruit is affected to some depth, although the progress of the disease is not so rapid downward as lat- erally. The pulp of the apple at the margin of the rotten region is usually bitter, thus giving rise to one of the common names of the disease. Fruit of any age after its formation is liable to infection if suitable climatic conditions and infective material obtain, though the disease is most noticeable and does most dam- age as the fruit approaches maturity. A series of hot, wet days favors a destructive attack, while cold checks it. The fruit as soon as it is badly rotted usually falls. 22. — Apple in advanced stage of bitter roi (glomerellose). After 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, bookdecade1910, bookyear1910
