Evaluating the Safety Profile of Cycloxaprid for Seed Treatment: Insights from Plant Uptake, Translocation, and Metabolism

The use of neonicotinoids in agricultural seed treatments faces increased scrutiny due to their adverse effects such as induced pollinator decline. Cycloxaprid is a promising alternative to traditional neonicotinoids with higher efficiency and improved safety profiles. This study systematically investigated the uptake, translocation, and metabolism of cycloxaprid in rice, maize, and water spinach after seed treatment, using ¹⁴C isotope tracing and high-resolution mass spectrometry. Results indicated that less than 11% of cycloxaprid was absorbed by the seedlings, with over 85% released into soils. Cycloxaprid predominantly accumulated in the roots and lower leaves, with minimal translocation to upper leaves or edible parts. Subcellular analysis revealed that cycloxaprid and its metabolites predominantly bonded with internal plant matrix molecules, limiting their transport within the plants. Additionally, seven metabolites of cycloxaprid were identified, and a preliminary metabolic pathway in plants was proposed. Compared to conventional neonicotinoids, cycloxaprid displayed lower potential for plant uptake and vertical translocation, thereby reducing risks to nontarget species like pollinators. These findings provide important theoretical support for the promotion of cycloxaprid as a safe seed treatment agent and offer new perspectives for the sustainable use and risk management of neonicotinoid pesticides.