Microencapsulated cyetpyrafen via interfacial polymerization: a sustainable controlled-release strategy against...

Microencapsulation offers a promising strategy for enhancing the sustainable control of Panonychus citri. In this study, cyetpyrafen (CPF)-loaded polyurethane microcapsules suspension (CCS) was synthesized via interfacial polymerization using isophorone diisocyanate (IPDI) and triethanolamine (TEA) as monomers, aiming to develop a pH-responsive controlled-release formulation with improved efficacy and reduced environmental impact.

Under the optimal preparation conditions of oil-to-water volume ratio (1:4.2, v/v), TEA (10%, w/w), and IPDI (2.5%, w/w), CPF-loaded microcapsules with a loading content of 46.46%, encapsulation efficiency of 72.24%, median particle diameter (D₅₀) of 8.03 μm, and a span of 5.93, were facilely prepared. The CCS demonstrated pH-responsive sustained release over 144 h, with cumulative release rates of 82.82% in acidic, 54.77% in neutral, and 30.29% in basic media. In contrast, a commercial suspension concentrate showed rapid release within 40 h, reaching 90.63%, 99.23%, and 83.45% in the respective media. Bioassay results revealed time-dependent acaricidal activity against Panonychus citri, with the median lethal concentration (LC₅₀) decreasing from 17.84 mg/L (24 h) to 2.07 mg/L (48 h), confirming the controlled-release behavior. Furthermore, the CCS showed favorable biosafety in cotton at recommended application doses.

This study presents an effective microencapsulation strategy for CPF that enhances pesticidal performance through controlled release while minimizing environmental risks. The optimized CCS formulation represents a sustainable alternative to conventional acaricides, with potential applications in integrated pest management. The developed methodology also provides a framework for designing advanced, multifunctional pesticide delivery systems with tailored release properties. © 2026 Society of Chemical Industry.