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Alternative control of Macrophomina phaseolina in soybean through the use of ozone

Marina Bracale: Universidade Estadual de Londrina

<div>The ozonation is an alternative method for the control of plant diseases. The objective of the study was to test the viability of ozone in the control of the fungus <em>Macrophomina phaseolina</em>. For the assay, Petri dishes with PDA culture medium containing <em>M. phaseolina</em> were used, which were maintained in BOD in the dark at 28°C. At 4 days of growth, the Petri dishes were opened and exposed to ozone for 25 minutes at total. Every five minutes, one treatment was withdrawn, totalizing 6 treatments with one control. Each treatment had 4 replicates. After exposure to ozone, the Petri dishes were maintained in BOD in the dark at 28°C until the mycelial growth of the control reached the edge of the dish. The evaluation consisted in measuring mycelial growth with the help of a pachymeter. The ozonation process was performed by an ozone generator unit coupled to a hermetically sealed chamber. Exposure to ozone occurred through indoor air circulation. The data were submitted to regression analysis and the models adjusted according to the coefficient of determination and beta parameters of the regression. The results obtained presented reduction of mycelial growth of the pathogen with the minimum exposure to ozone. The ozonation technique presented viable results for improvement and execution of more studies. The present work requires repetition and possible addition of longer periods of exposure.</div>