Designing Veratramine Nanopesticide with Strong Adhesion Performance and Plant Uptake for Efficient Control toward Multiple Target Pests

Botanical pesticides are promising alternatives for sustainable pest management due to their environmental compatibility, biodegradability, and multitarget mechanisms that help delay pest resistance. Unfortunately, most botanical pesticides face challenges such as limited water solubility and poor foliar adhesion, thereby limiting their large-scale field application. Herein, the star polycation (SPc) nanocarrier and X-100 surfactant were introduced to successfully develop an efficient nanodelivery platform for veratramine (VAM). The SPc could spontaneously assemble with VAM via a hydrogen bond and van der Waals force, and the integration of Triton X-100 stabilized the nanoscale size (84 nm) to prepare a VAM nanopesticide. Interestingly, this optimized system reduced the contact angle and increased the retention of VAM on plant leaves while remarkably facilitating its systemic transport through roots and leaves. Compared to commercial VAM, the VAM nanopesticide showed stronger contact and stomach toxicity against multiple pest species such as aphids, thrips, and mites, which exhibited fast-acting properties in the field with high control efficacy even at 7 d after the spraying. Subsequently, the RNA-seq and biological experiments demonstrated that the application of VAM nanopesticide influenced various pathways in aphids, inducing starch and sucrose metabolism, protein digestion and absorption, etc., with inhibitory effects on the biosynthesis of trehalose and protein. Importantly, the application of the VAM nanopesticide did not adversely influence the predatory lady beetles or cowpea seedlings, confirming its safety in actual applications. Overall, our work addressed the formulation instability and environmental loss of VAM while ensuring its ecological safety, which offered a scalable nanoplatform to optimize botanical pesticides for enhanced efficacy and minimized ecological risks.