Of the four essential oils tested, clove oil, cinnamon oil and lemongrass oil exhibited strong inhibitory effects on B. cinerea, since they completely suppressed the mycelial growth of the fungus at 15 μL (MIQ = 15 μL). However the headspace vapors of galingale oil exhibited weaker inhibitory effect (MIQ = 25 μL) (Table 1).
The lemongrass oil and clove oil appeared to possess the strongest antifungal activity against B. cinerea since it allow only minimal growth of the fungi at 10 μL and a few growth at 5 μL dose (Table 1). Lee et al. (2007) tested lemongrass oil (Cymbopogon citrates) as a fumigant against B. cinerea, but in contrast to this study their results were negative. This may be because Lee et al. (2007) only applied 1 μL of oil for each treatment, which less than the MIQ level we found in this study.