Effects of Some Plant Essential Oils against Fungi on Wheat Seeds

Diseases, especially caused by seed borne fungi, are among the factors decreasing yield and quality of wheat. Common bunt is also an important seed borne disease of wheat worldwide. The objective of the study is to determine the effects of clove, ginger, mint, oregano and thyme oils on the fungal load of wheat seeds. In addition, effects of the oils on the germination rates of bunt spores were investigated. Blotter method was used to determine the effects of different concentrations (0.05 – 10%) of the oils on fungal load of wheat seeds. After incubation at 22°C for 7 days, seeds were investigated under stereomicroscope and fungi growing on the seeds were recorded. Germination rates of bunt spores were determined after incubation on water agar with different concentrations of oils. Highest doses of clove, mint and oregano oils totally inhibited the fungal growth on wheat seeds, but they also inhibited the germination of seeds. Lower doses failed to inhibit fungi on seeds, however they decreased or totally inhibited the germination of bunt spores. As a result, it was found that plant essential oils could be used against bunt disease of wheat as an alternative to fungicides.