A Comparison of Different Estimation Methods for Fungicide EC₅₀ and EC₉₅ Values

Abstract

Abstract EC 50 and EC 95 (the effective concentrations to cause inhibitions by 50 and 95%, respectively) are commonly used to express fungicide potency. Different methods are currently employed to calculate EC 50 and EC 95 values. In this study, EC 50 and EC 95 values for fungicide epoxiconazole against 34 isolates of S clerotinia sclerotiorum were calculated with seven different methods. Results showed that for both EC 50 and EC 95 calculations, there was no significant difference among three statistical programs IBM spss ® , GraphPad Prism ® and dps ® (P ≥ 0.066). Methods linear log (linear regression of mycelial growth inhibition vs. logarithmic concentration) and interpolation log (linear interpolation from inhibition and logarithmic concentration data) were not significantly different (P ≥ 0.058) from IBM spss in EC 50 calculations. These results indicate that among the seven methods, the three statistical programs IBM spss , GraphPad Prism, dps and linear log method are appropriate for EC 50 calculations. But for EC 95 calculations, only the three statistical programs are recommended, and GraphPad Prism is likely to give a little higher values than spss and dps .