Optimization of lemongrass essential oil nanoemulsion formulation and antifungal activity against <i>Colletotrichum musae</i> QB6 causing anthracnose in bananas

Response Surface Methodology (RSM) was used in this study to optimize the formulation of lemongrass essential oil nanoemulsion (LEO-NE) for improved stability and antifungal activity. The formulation of LEO-NE was optimized using a Box-Behnken Design (BBD), which examined the effects of Tween-80 (T-80) concentration, stirring speed, and ultrasonic time on droplet diameter (DD) and polydispersity index (PDI). The optimized nanoemulsion showed a DD of 153.2 nm and a PDI of 0.22 after being prepared with a T-80 concentration of 17.22 g/L, a stirring speed of 10,180 rpm, and an ultrasonic treatment time of 20 min. For more than 120 days, this formulation showed exceptional stability at room temperature. Furthermore, Colletotrichum musae ( C. musae ) QB6, the causative agent of banana anthracnose, was effectively inhibited by the optimized LEO-NE. Musa AAA bananas were used for both in vitro and in vivo testing. The antifungal activity of the LEO-NE was significantly higher than that of pure lemongrass essential oil (LEO) and benzimidazole. These results demonstrate the promising potential of optimized LEO-NEs as safe, environmentally friendly substitutes for synthetic fungicides in fruit preservation, providing improved stability and bioefficacy for use in farming.