The effect of the mixtures on P. myriotylum was determined in radial growth experiments as described above. The treatment groups were: a) control group (PDA containing DMSO); b) E. adenophorum oil extracts in PDA; c) E. adenophorum oil extracts combined with a commercial fungicide (mefenoxam, mancozeb, iprodione or azoxystrobin) in PDA; and d) individual commercial fungicide in PDA. The interactive effect of the mixed components was evaluated using the formula provided by Colby [21, 22]: Exp=XAYB/100 In this equation, Exp = the expected mycelial growth inhibition rate of the mixture, XA = mycelial growth inhibition rate of E. adenophorum oil extracts alone, YB = mycelial growth inhibition rate of commercial fungicides (mefenoxam, mancozeb, iprodione or azoxystrobin) alone, Obs = the observed mycelial growth inhibition rate of the mixture. The synergism ratio (SR) is calculated as the ratio between Obs and Exp. If SR = 1, there is additive; If SR > 1, there is synergism; If SR < 1, there is antagonism.