Deposition, Distribution, Metabolism, and Reduced Application Dose of Thiamethoxam in a Pepper-Planted Ecosystem

Mei, Jiajia; Ge, Q. X.; Han, Lingxi; Zhang, Houpu; Long, Zhengnan; Cui, Yanli; Hua, Rimao; Yu, Yunlong; Fang, Hua

doi:10.1021/acs.jafc.9b02645

Cited by 22 publications

(4 citation statements)

References 25 publications

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“…It was reported that the dissipation rate of TMX depended on a variety of factors, including soil characteristics, pH values, application dose, climatic or cultivation conditions, microorganisms, organic fertilizer use, and so on [ 32 , 33 ]. The half-lives of TMX vary from 3.9 d to 94.1 d, or even longer periods, in different soil types and plant ecosystems such as pepper, citrus, tobacco, and Swiss chard [ 22 , 34 , 35 ]. The persistence of TMX in soil can be affected by introducing organic amendments such as biochar and microbial activity to accelerate degradation by Pseudomonas and Bacillus [ 36 , 37 ].…”

Section: Resultsmentioning

confidence: 99%

Dissipation, Bioconcentration and Dietary Risk Assessment of Thiamethoxam and Its Metabolites in Agaricus bisporus and Substrates under Different Application Methods

Chen

Zhang

Rao

et al. 2023

Toxics

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In order to acquire scientific evidence for the application of thiamethoxam (TMX) in Agaricus bisporus cultivation, residue and dissipation experiments for field trials were performed with the application of TMX in compost and casing soil, respectively. An effective QuEChERS method was established to analyze TMX and its two metabolites, clothianidin (CLO) and thiamethoxam-urea (TMX-urea), in compost, casing soil, and fruiting bodies. The results indicated that the TMX dissipation half-lives (t1/2) at dosages of 10 and 50 mg kg−1 were 19.74 d (day) and 28.87 d in compost and 33.54 d and 42.59 d in casing soil, individually. TMX, CLO, and TMX-urea were observed after TMX application in compost and casing soil. For TMX applied to the casing soil, only TMX residues were detected in fruiting bodies with bioconcentration factors (BCFs) of 0.0003~0.0009. In addition, both the chronic risk quotient (RQ) and acute risk quotient (HQ) values of TMX in fruiting bodies were far less than 1, which means the dietary health risks to humans were acceptable. However, in the TMX application to the compost, these analytes were not detected in the fruiting bodies. This suggested that the application of TMX in compost was safer than in casing soil during A. bisporus cultivation.

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Section: Resultsmentioning

confidence: 99%

Dissipation, Bioconcentration and Dietary Risk Assessment of Thiamethoxam and Its Metabolites in Agaricus bisporus and Substrates under Different Application Methods

Chen

Zhang

Rao

et al. 2023

Toxics

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“…The residual CHL and CYN detected from plants suggest plant root uptake and transport of these pesticides, although their amounts in plants tended to decrease through the cultivation period. Similarly, the distribution of insecticides in plant parts decreased with an increased pesticide exposure period [ 1 , 25 , 26 ]. Although our study did not focus on the metabolites of CHL and CYN, there are reports that the amount of metabolites relative to the parental compound (CYN) increased [ 1 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Stable Isotope Analysis of Residual Pesticides via High Performance Liquid Chromatography and Elemental Analyzer–Isotope Ratio Mass Spectrometry

et al. 2022

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To broaden the range of measurable pesticides for stable isotope analysis (SIA), we tested whether SIA of the anthranilic diamides cyantraniliprole (CYN) and chlorantraniliprole (CHL) can be achieved under elemental analyzer/isotope ratio mass spectrometry with compound purification in high-performance liquid chromatography (HPLC). Using this method, carbon isotope compositions were measured in pesticide residues extracted from plants (lettuce) grown indoors in potting soil that were treated with 500 mg/kg CHL and 250 mg/kg CYN and were followed up for 45 days. Our results show that the CYN and CHL standard materials did not have significant isotope differences before and after clean-up processing in HPLC. Further, when applied to the CYN product and CHL product in soil, stable isotope differences between the soil and plant were observed at <1.0‰ throughout the incubation period. There was a slight increase in the variability of pesticide isotope ratio detected with longer-term incubation (CHL, on average 1.5‰). Overall, we measured the carbon isotope ratio of target pesticides from HPLC fraction as the purification and pre-concentration step for environmental and biological samples. Such negligible isotopic differences in pesticide residues in soils and plants 45 days after application confirmed the potential of CSIA to quantify pesticide behavior in environments.

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“…Mei et al found in their study on thiamethoxam for controlling white powdery mildew in peppers that the appropriate dilution level significantly impacts the deposition of the solution on leaf surfaces, and both over-dilution and under-dilution are not conducive to the deposition of the solution on leaf surfaces. 22 In their study on fungal infection of wheat, Song et al found that slightly diluted solutions are difficult to wet and tend to rebound from the leaf surface. 23 Given this, pesticide carriers can effectively improve the effective deposition of droplets on leaf surfaces.…”

Section: Introductionmentioning

confidence: 99%

Understanding dilution effects on particle‐containing pesticide droplets deposition on rice leaf via developing CFD‐VOF‐DPM model

Chaoxi,

Yubin,

Yunfu

et al. 2024

Pest Management Science

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BACKGROUNDPesticide dilution is one of the essential aspects of plant protection. However, the effect of dilution on the deposition characteristics of pesticide droplets containing particulate additives on crop leaf surfaces remains unclear and warrants further research. Herein, a validated computational fluid dynamics (CFD)‐volume of fluid (VOF)‐discrete phase model (DPM) numerical model was developed to analyze the influence of particle content on the deposition behavior of droplets on the leaf surface comparatively, taking into account the particle content of different diluted thifluzamide solutions. Additionally, the study aimed to analyze further the kinetic behavior of pesticide droplets landing on rice leaves across different dilution conditions.RESULTSPesticide droplets diluted 100‐fold had a lower retraction rate during spreading than particle‐free droplets, so the solution is more easily deposited in the leaves. Moreover, the low dilution (high concentration) increased the critical adhesion rate between droplets and rice leaves, inhibiting the bouncing of droplets on the leaf surface, thus promoting their effective deposition on the surface. In addition, low dilution (high concentration) is not conducive to spreading droplets when the impact velocity is high, and it also results in a large amount of pesticide use.CONCLUSIONThe actual application process can be through understanding the dilution factor of the configured pesticide solution, and reasonable adjustment of the nozzle pressure can effectively improve the utilization rate of pesticides and reduce the pollution brought by pesticides to the environment. These results provide an essential reference for studying pesticide droplet deposition characteristics, including rice plant protection and spraying technology. © 2024 Society of Chemical Industry.

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Deposition, Distribution, Metabolism, and Reduced Application Dose of Thiamethoxam in a Pepper-Planted Ecosystem

Cited by 22 publications

References 25 publications

Dissipation, Bioconcentration and Dietary Risk Assessment of Thiamethoxam and Its Metabolites in Agaricus bisporus and Substrates under Different Application Methods

Dissipation, Bioconcentration and Dietary Risk Assessment of Thiamethoxam and Its Metabolites in Agaricus bisporus and Substrates under Different Application Methods

Stable Isotope Analysis of Residual Pesticides via High Performance Liquid Chromatography and Elemental Analyzer–Isotope Ratio Mass Spectrometry

Understanding dilution effects on particle‐containing pesticide droplets deposition on rice leaf via developing CFD‐VOF‐DPM model

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