In vitro and In vivo Evaluation of Antifungal Activity of Essential Plant Oils against Fusarium Wilt of Sesame

Fusarium wilt, caused by the genus Fusarium, is a fungal disease that is a major threat to the health of sesame plants in Burkina Faso. To reduce the incidence of the disease, most farmers abuse synthetic pesticides. These pesticides have negative effects on the environment and human health, and confer resistance to pathogens. With the aim of finding alternatives to the use of synthetic pesticides as a means of control, essential oils of Cymbopogon schoenanthus, Eucalyptus camaldulensis, Ocimum americanum and Lippia multiflora, used alone or in combination, were evaluated In vitro and in vivo for their inhibitory activity against Fusarium duofalcatisporum and F. proliferatum, two pathogenic isolates of sesame. Each product was tested In vitro at the dose of 1% and in greenhouse under artificial seed contamination at the doses of 0.5%, 1%, 1.5% and 2%. The promising treatments were then tested in greenhouse under natural seed contamination at the dose of 0.5%. The experimental designs employed included a completely randomized design with Fisher's blocks for the in vitro tests and a split-plot design for the in vivo tests. All treatments used in vitro significantly reduced the growth of F. duofalcatisporum (62.16-89.97% growth reduction) and F. proliferatum (33.70-85.08%) compared to the untreated control; seven of these treatments reduced fungal growth more (73.33-89.97% growth reduction) than Calthio C (62.34-76.70% growth reduction). In vivo, among the applied doses, the 0.5% dose distinguished from the others by its high emergence rate (93.05-96.52%) and high rate of normal plants. The same dose applied to natural infected seeds by Fusarium, significantly reduced the infection rate (≤ 8.5%) compared to the control, which had an infection rate of 67%. A validation of this study on farm would be necessary to propose these essential oils as alternatives to chemical fungicides for the management of Fusarium wilt in sesame.