Investigation of the Impact of a Pesticide Adjuvant on Dimethoate Persistence, Penetration, and Stability on Apples Using Surface-Enhanced Raman Spectroscopy
Danhui Wang, Xinyi Du, Lili He
Abstract
Pesticides are often applied with adjuvants to improve their efficacy and stability. However, the knowledge about pesticide behaviors with adjuvants is still lacking. This study investigated the impact of a common adjuvant on the persistence and penetration of dimethoate on and in apples and dimethoate stability in washing solutions using the surface-enhanced Raman spectroscopic (SERS) mapping technique. Results demonstrated that the adjuvant did not significantly affect dimethoate removal after postharvest washing or dimethoate penetration (30 ± 5 μm) in apples. Tap water showed similar effectiveness as baking soda to remove dimethoate with and without the adjuvant in 5 min. Dimethoate with and without the adjuvant was stable in tap water but was degraded to omethoate in the baking soda rapidly in 40 min. Considering the higher toxicity of omethoate, tap water would be recommended to remove dimethoate compared with baking soda. The study provides a better understanding of adjuvant effects on pesticide behaviors.