Construction of a nontoxic nano-pesticide and its co-application with natural predators for perfect cooperative pest management: an innovative strategy for pesticide reduction

Abstract

Historically, the widespread and unscientific application of chemical pesticides has posed serious threats to the ecosystem and human health. Hence, there is an urgent need for efficient alternative technologies for green pest management. In this context, the current study developed a nontoxic nano-pesticide and co-applied with natural predators with enhanced bioactivity toward insect pests, and co-applied the nano-pesticide and predator to propose an innovative pest control technique. The bio-toxicity of the star cationic polymer (SPc) for use in the nano-pesticide preparation was first evaluated with widely applied predatory stinkbug Arma custos. The SPc exhibited negligible toxicity to both the eggs and nymphs of the predators; however, its extremely high concentration led to nymph death, with a lethal concentration 50 (LC₅₀) value of 14.75 mg mL⁻¹via oral feeding. This SPc at an extremely high concentration primarily induced a considerable stress response in the predator, which augmented the processes of phagocytosis, exocytosis, and energy synthesis and ultimately led to its death. Subsequently, we developed a self-assembled tetraniliprole (TTP)/SPc complex via hydrogen bonding and van der Waals interactions, which disrupted the self-aggregated structure of TTP and reduced its particle size by nearly 10 fold. Impressively, the contact and stomach toxicity of SPc-loaded TTP were significantly improved against common cutworm Spodoptera litura, with corrected mortalities increasing by approximately 30%. Importantly, the predators displayed a strong predation selectivity for alive pests, while the application of the nano-pesticide did not show any negative influences on the predators. Thus, the co-application of the nano-pesticide and predatory stinkbug could achieve efficient pest control. In summary, a nontoxic nano-pesticide was successfully developed to be co-applied with a predator, which not only represents an innovative technology solution for green pest management but also would be beneficial for reducing the use of pesticides to minimize their adverse impacts on the environment.