Investigating the Impact of Crop Oil Concentrate on the Persistence and Penetration of Pesticides Applied on Apples

Abstract

The present study systemically investigated the influence of crop oil concentrate (COC) on the pesticide behavior on apples. Surface-enhanced Raman scattering was employed to monitor the persistence and penetration of carbaryl (a systemic insecticide) and thiram (a nonsystemic fungicide). The results revealed that COC significantly enhanced the penetration depth of carbaryl by 38.7% and increased the relative Raman intensity within plant tissue (Z = −120 μm) by 81.3% after 1-day exposure. Liquid chromatography with tandem mass spectrometry confirmed that COC increased the internalized carbaryl residues by 176.6%. For thiram, COC reduced its persistence when exposed to NaHCO₃ hydrolysis, decreasing removal efficiency by 38.96% after 1 day and 38.13% after 3 days, while not affecting its penetration profile. These findings highlight COC’s potential to enhance systemic pesticide penetration while facilitating the removal of surface residue, offering valuable insights for developing safer and more effective pesticide application strategies.