Efeito fungitóxico de óleos essenciais de hortelã (Mentha sp.) e eucalipto (Eucalyptus spp.) em Macrophomina phaseolina (Tassi.). Goid.

Abstract

Macrophomina phaseolina (Tassi.). Goid is the etiological agent of one of the major diseases in cowpea bean crop, commonly known as gray rot stem. Due to the lack of registered phytosanitary products to control this disease, the search for alternative control methods is increasingly common. The objective of this study was to evaluate the effect of essential oils on the mycelial growth of M. phaseolina. The oils tested were Mentha sp. and Eucalyptus spp., at concentrations of 0.4; 0.6; 0.8 and 1.0%. The work was conducted in Phytopathology Laboratory of the Federal University of Campina Grande. Daily measurements of the colony diameter were performed in two perpendicular directions until it filled the entire surface of the culture medium of one of the plates. The experiment was conducted in a completely randomized experimental design in a factorial arrangement 2 x 5 + 1, with ten treatments plus a positive control, consisting of the supplemental application in the medium (BDA) of the fungicide Sportak 450 EC (Procloraz), and five replications. The data were submitted to variance analysis and the means were compared by the Tukey and Scott Knott test at a 5% probability to evaluate the effect of the treatments on the mycelial growth rate (mm day-1), growth inhibition percentage (%) and mycelial growth rate index, respectively. The Mentha sp. essential oil presented a potential of inhibition of the fungus close to that obtained by the fungicide, different from the Eucalyptus spp. oil that did not obtain an efficient response.