Ethanolic extract of Senna alata in the control of Myrothecium roridum, causal agent of myrothecium leaf spot

摘要

The fungus M. roridum is the causal agent of the myrothecium Leaf Spot disease in melon, being responsible for great losses in the production of this olericulture. This disease is difficult to control, since its agent inhabits the soil. Seeking for alternative forms of control, this work aimed to evaluate the effect of the activity of ethanolic extracts of parts of S. alata on M. roridum. The experimental design was completely randomized and distributed in a factorial scheme 4 x 6 + 1, with the first factor being parts of the plant (stalk, flower, root and green bean), and the second factor, six concentrations (0.25; 0.50, 50, 75, 250 and 500 µg mL-1), plus a control, with four repetitions per treatment. The available variables were: mycelial growth rate (MGR), mycelial growth inhibition (MGI) and area below mycelial growth curve (ABMGC). All the extracts of the S. alata parts were found to be efficient in inhibiting mycelial growth of M. roridum. The green bean ethanolic extract was the best inhibitor of the growth of M. roridum growth at the concentration of 500 µg mL-1, followed by the root and stalk extracts.