Although previous studies have highlighted the antifungal activity of plant extracts or essential oils from E. adenophorum, few have demonstrated morphological and ultrastructural changes to fungi. Light microscope observations of the microstructure of P. myriotylum revealed several mechanisms by which E. adenophorum oil extracts effect this fungal pathogen. Degenerative changes in cell inclusion and hyphal morphology were commonly observed, including cytoplasm granulation, lack of cytoplasm, increased hyphal diameter and cell wall decay (Fig 5). The changes indicated that the cell wall, cell membrane and cytoplasm may be the targets for E. adenophorum oil extract components. However, not all of these cellular components are separate targets. Some targets may be affected as a consequence of another mechanism being activated by the oil extract components . It is likely that attacks at multiple cellular targets will eventually lead to cell death.