In vitro and in vivo evaluation of citronella essential oil and its compounds in the control of fusarium wilt in tomato plants

Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici is one of the most significant diseases affecting tomato cultivation, leading to substantial economic losses. In response to the growing demand for sustainable alternatives to chemical pesticides, essential oils have emerged as a promising solution for managing phytopathogens. This study investigated citronella essential oil ( Cymbopogon winterianus ) and its major compounds (citronellal, geraniol, and citronellol) as natural alternatives for controlling F. oxysporum f. sp. lycopersici , the causative agent of Fusarium wilt in tomatoes. Chemical analysis identified citronellal as the primary compound, followed by geraniol and citronellol. In vitro tests demonstrated significant antifungal activity, with geraniol and citronellol achieving IC ₅₀ values of 0.144 µL.mL⁻¹ and 0.207 µL.mL⁻¹, respectively, resulting in 100% inhibition of fungal mycelial growth at certain concentrations. Citronellal showed a fungistatic effect with 46% inhibition at 0.500 µL.mL⁻¹, suggesting a role in controlling fungal proliferation without causing complete fungal death. In vivo assays confirmed that geraniol effectively reduced Fusarium wilt symptoms in Santa Cruz tomato plants, achieving comparable effects to commercial fungicides at a concentration of 0.610 µL.mL⁻¹, and thus indicating its potential as a sustainable alternative for plant disease management. These findings underscore the promise of citronella oil and its major components as eco-friendly antifungal agents in agriculture.