Nanodelivery Improves Insecticidal Activity of Hexaflumuron against Apolygus lucorum by Inhibiting the Synthesis of Insect Cuticle Protein.

Given the limitations of conventional pesticides, sustainable pest control alternatives are urgently needed. Hexaflumuron (HE), an insect growth regulator, is a potential candidate, yet its efficacy requires enhancement. This study developed a star polycation (SPc)-based nanocarrier to improve HE delivery. The HE/SPc complex was formed via electrostatic and van der Waals interactions, reducing the particle size from 751.21 to 174.62 nm. Compared to HE alone, HE/SPc complex enhanced retention and coverage for effective foliar application, and significantly enhanced insecticidal activity against Apolygus lucorum nymphs. It prolonged nymphal development, increased mortality, and reduced the body weight. Mechanistically, HE/SPc down-regulated cuticle-related genes, impairing cuticle formation and elevated detoxification enzyme activities (CYP450, CarE, GSTs). Additionally, SPc reduced the HE phytotoxicity in bean seeds. This work established a promising SPc-based delivery platform for insect growth regulators and offered a design strategy for novel and efficient pesticide formulations.