Effect of essential oils from plants of the genus Lippia on Fusarium oxysporum f. sp. lycopersici

The tomato (Solanum lycopersicum) is among the most cultivated vegetables, and Brazil is one of the largest producers. The fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici, is one of the most important diseases of tomato. Thus, this study aimed to evaluate the effect of different concentrations of essential oils of Lippia sidoides and Lippia gracilis on the fungus Fusarium oxysporum f. sp. lycopersici race 3. Qualitative and quantitative analyses were performed in the essential oils of the species tested using a system of Gas chromatography-Mass Spectrometry (GC-MS) and flame ionization detector (GC-FID), respectively. The identification of the oil constituents was performed by comparing their mass spectra with spectra from the literature and databases and comparison of retention rates. Concentrations used were 0.3, 0.6, 0.9, 1.2 and 1.5 mu L mL(-1) of essential oils. The essential oil was added to the PDA, and then poured into Petri dishes. Each plate was inoculated with a record growth of the pathogen. The evaluations were performed daily by measuring the diameter of the colonies. The antifungal activity of essential oils at 100% was demonstrated in all concentrations, except at a concentration of 0.3 mu L mL(-1), where only 70.2% of mycelial growth was inhibited.