Rhamnolipid-Stabilized Essential Oils Nanoemulsions: Sustainable Biopesticides and Biostimulants with Potential for Crop Protection

The search for environmentally friendly solutions to effectively control crop pests while safeguarding human health has become a global priority. One promising strategy is to enhance plant defenses by pre-inducing their innate immune system. In this study, we developed rhamnolipid (RL)-stabilized nanoemulsions (NEs) encapsulating essential oils (EOs) as potential biopesticides and biostimulants for agroindustrial applications. These NEs were designed to improve the solubility and stability of EOs while effectively combining their insecticidal and/or repellent activities with the bioactive properties of RLs. In this regard, our interdisciplinary approach involved formulating and characterizing these NEs and evaluating their stability and wettability on plant leaf surfaces. We further evaluated their effects on bacterial growth in vitro and in the model plant Arabidopsis thaliana, along with their impact on beneficial soil microorganisms. We analyzed their ability to stimulate the plant’s immune system and their impact on the viability and reproduction of the aphid Myzus persicae. Additionally, we explored whether RLs stimulate plant defenses through alterations in the leaf cuticle. Our findings demonstrate that RL-stabilized EO-NEs are effective bioprotectants and biostimulants in the model plant, offering a sustainable alternative that could reduce reliance on chemical pesticides in agriculture.