Antifungal activity of plant essential oils against Verticillium dahliae Klebahn, the causal agent of verticillium wilt of pepper

Biofungicides based on plant oils have some advantages compared to chemical fungicides, especially considering their harmful effect on the environment. Twenty-two essential oils from Germany and Albania were assayed for inhibitory and fungicidal activity against Verticillium dahliae Klebahn, the causal agent of Verticillium wilt of pepper, using the macrodilution fumigant method. The concentrations of oils obtained in the vapour phase were: 0.02, 0.04, 0.08, 0.16 and 0.32 ?l ml-1 with determined minimum inhibitory and fungicidal concentrations. The strongest activity was shown by two samples of mint oil (Mentha piperita L.) at 0.02 ?l ml-1 of air, both from Germany and Albania, followed by plant essential oils of eucalyptus (Eucalyptus globulus Labilardie), black pine (Pinus nigra L.) and cade (Juniperus oxycedrus L.), and all of them were lethal to the pathogen. Nine oils: two samples of mint, cade, eucalyptus, black pine, lavender (Lavandula angustifolia Mill.), sage (Salvia officinalis L.) and rosemary (Rosmarinus officinalis L.) inhibited the growth of Verticillium dahliae, while five oils (two samples of mint, eucalyptus, black pine and cade) showed fungicidal effects on the pathogen. These results showed that mint, eucalyptus, black pine and cade essential oils have a potential for further in vivo experiments against Verticillium dahliae.