Effect of Biorational fungicides on in vitro growth of Monilinia fructicola
2015
Lalancette, N. | McFarland, K. A.
The biofungicides potassium bicarbonate, Bacillus subtilis, and hydrophobic extract of neem oil were examined in vitro for their efficacy at inhibiting growth of Monilinia fructicola. Petri plates containing potato dextrose agar (PDA) were amended with each biofungicide at six different concentrations in a logarithmic series. Discs of a single-spore isolate of M. fructicola (Mf012) were transferred from PDA cultures to each biofungicide-amended plate. Growth on non-amended agar was used as a control. After four days at 25°C in the dark, the diameter of colony growth was measured. The dependent response variable was calculated as growth on amended agar / growth of the control. Examination of the linear response-log dose curves revealed that all three biofungicides were capable of inhibiting mycelial growth. To quantitatively evaluate efficacy, the logistic decline model was fit to each response-dose curve using nonlinear regression analysis. The effective dose at which growth is inhibited by 50% (ED50) was estimated as 0.086, 0.104, and 3.53 g a.i./L for potassium bicarbonate, B. subtilis, and neem oil, respectively. These results indicate that potassium bicarbonate has the greatest intrinsic efficacy with respect to inhibition of mycelial growth.
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