Control of Sugarcane Smut Disease: Evaluation of the In vitro Fungitoxicity of Three Essential Oils

The sugarcane smut disease caused by Sporisorium scitamineum occurs in all production areas. In order to contribute to the management of this disease, a study was carried out in vitro conditions. The aim of this study was to evaluate the antifungal efficacy and to determine the inhibitory concentration of the essentials oils of Ocimum gratissimum, Zingiber officinale and Cymbopogon citratus upon two strains B and Z of Sporisorium scitamineum. These oils were tested on mycelial growth of colonies, spores’ production and teliospores germination. The results showed a variable fungitoxic effect of the oils according to doses. Mycelial growth and spores production were totally inhibited (100%) from 1000 ppm by all the oils. The 90% inhibitory concentrations (IC90) obtained were 880.37 ppm, 847.83 ppm and 805.75 ppm for Ocimum gratissimum, Zingiber officinale and Cymbopogon citratus, respectively. The germination of teliospores was completely reduced by the three essential oils from 500 ppm upwards. Propiconazole had strong inhibitory effects at 400 ppm with a very low IC50 and the IC90 ranged from 305 ppm to 323.36 ppm. Moreover, at the level of the strains, no difference in resistance was observed These oils could provide a good means of controlling sugarcane smut.