Table 2 shows the relative growth inhibition of P. myriotylum to mixtures of E. adenophorum oil extracts and the synthetic fungicides: azoxystrobin, iprodione, mancozeb and mefenoxam. Importantly, all combinations of the oil extracts and these synthetic fungicides showed substantial synergistic effects on the mycelial growth of P. myriotylum. The synergism ratios (SR) ranged from 2.07 to 33.29 for the tested combinations of oil extracts and fungicides. Mancozeb alone (20 μg/ml) and a very low concentration of oil extracts alone (5 μg/ml) inhibited growth by 80.47% and 6.95%, respectively. However, the same concentrations of fungicide and oil extracts mixed together completely inhibited mycelial growth. Complete growth inhibition of P. myriotylum was also observed using a mixture of 100 μg/ml iprodione + 50 μg/ml oil extracts, compared with only 22.52% reduction in mycelial growth when 100 μg/ml iprodione was used alone. The oil extracts appear to synergise the effects of relatively low concentrations of mancozeb and iprodione fungicides against P. myriotylum.