Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Population changes of Macrophomina phaseolina in amended soils(Transactions of the British Mycological Society, 1980-06) Santos Filho, Edgar; Dhingra, Onkar D.Population changes of Macrophomina phaseolina (Tassi) Goid. were followed in two soils amended with either wheat, corn, bean or alfalfa straw, or with nitrogen-enriched wheat straw or glucose and sodium nitrate at different C:N ratios. The population declined significantly initially in both soils with any amendment but later increased in soils amended with wheat or corn straw and in one soil amended with bean or alfalfa straw. Population declined with no subsequent increase when soil was amended with nitrogen-enriched wheat straw or glucose and sodium nitrate at C:N ratios equal to that of the natural plant residues. In general the population declined more rapidly when soil was amended with nitrogen-enriched wheat straw or glucose and nitrogen than if amended with either corn, bean or alfalfa straw and when soil was amended with low C:N ratios.Item Effect of soil temperature, moisture, and nitrogen on competitive saprophytic ability of Macrophomina phaseolina Author links open overlay panel(Transactions of the British Mycological Society, 1981) Dhingra, Onkar D.; Chagas, DaniloThe effect of soil temperature, moisture and nitrogen on saprophytic colonization of bean or wheat stems by Macrophomina phaseolina was studied in two soils. Maximum colonization of the substrate units occurred at 15–20° and decreased with increasing soil temperature. At 15° more wheat than bean stems were colonized whereas at higher temperatures the reverse occurred. Maximum colonization of substrates occurred at 15–25% of moistureholding capacity, and percentage colonization decreased with increasing soil moisture. Addition of nitrogen to soil completely inhibited saprophytic colonization.Item Effect of herbicides on competitive saprophytic colonization by Macrophomina phaseolina of soybean stems(Transactions of the British Mycological Society, 1982-10) Dhingra, O. D.; Cerkauskas, R. F.; Sinclair, J. B.The effect of paraquat, glyphosate and sodium chlorate : sodium borate (50:50), applied at commercial rates was tested on the competitive saprophytic colonization by Macrophomina phaseolina of greenhouse and field grown soybean stems at three different growth stages in two soils. A significant difference in colonization was recorded between herbicide treatments and controls in soil with a high organic content but no significant difference in colonization was found between herbicides. The highest levels of stem colonization occurred 10 days after incubation in soil. Colonization in treated and untreated stems progressively declined at similar rates for all growth stages and in both soil types. In both soils, field stems had greater levels of colonization when sampling time and herbicide factors were excluded. The nonpersistence of M. phaseolina in stems in soil suggests that the saprophytic activity of the fungus does not effectively increase its inoculum density in soil.