EFFICACY OF FOUR ESSENTIAL OILS ON FUSARIUM HEAD BLIGHT CAUSED BY FUSARIUM OXYSPORUM F. SP. RADICIS LYCOPERSICI (FORL), A FUNGAL TELLURIC PATHOGEN OF TOMATO GROWN UNDER COVER

Fusarium head blight caused by Fusarium oxysporum f. sp. Radicis-lycopersici (FORL) is a constraint to tomato cultivation in Korhogo, Côte dIvoire. To control this disease, the antifungal activity of essential oils extracted from certain plants was evaluated in comparison with that of a synthetic fungicide for use. In vitro tests were performed on the different life stages of FORL. The in vivo evaluations consisted in carrying out two modes of treatment (curative and preventive) on plants of a susceptible variety of tomato inoculated with FORL. The results showed that the essential oils significantly reduced the different life stages of F.oxysporum f. sp. Radicis-lycopersici (FORL) as did the synthetic product. Thus, the essential oil Cymbopogon citratus at concentrations of 4000 and 6000 ppm strongly inhibited in vitro the different stages of FORL. In preventive and curative treatment, the essential oils not only improved the growth parameters of tomato plants but also reduced the incidence and severity of diseases. Thus, it was found that Cymbopogon citratus (4000 ppm) in preventive treatment, and Banko plus (250 ppm) in curative treatment reduced the mortality rate of FORL up to 6.66% and improved the growth parameters and reduced the flowering time of the tomato plant.The essential oil of C. citratus could be used for biological control of F. oxysporum f. sp. Radicis lycopersici.