Imidacloprid Residues Research Articles

Eco-friendly and sustainable approaches against aphids management (Myzus persicae) and dissipation studies of imidacloprid in important cash crop capsicum under protected and open condition

Capsicum is generally infested with many biotic agents mainly sucking insects, among them the major is aphid (Myzus persicae). Chemical management is one of the most common strategies for their management. However, there are no recommended insecticides for insect management in polyhouse. An experiment was designed to assess the bio-potency of four popularly used insecticides (Imidacloprid-17.8SL, Acephate-75SP, Dimethoate-30EC and Buprofezin-25SC), a botanical (Neem oil 10000 ppm) and two entomopathogenic fungi (Metarhizium anisopliae 1.15%WP and Lecanicillium lecanii 1.15%WP) for two consecutive seasons. Most effective and the highest reduction of aphid population (78.14–81.92 %) were found in imidacloprid (17.8SL) treated plots. This effective molecule imidacloprid was further studied for its dissipation pattern under polyhouse and open condition and found that the imidacloprid residues in capsicum fruit dissipated below quantification limit (BQL) within 10days after final spray and the residues in the soil sampled at harvest time were found below the detection level. The half-lives of imidacloprid were 1.88 and 2.61 days under polyhouse and 1.07 and 1.52 days in open field at recommended doses (25 g a.i. ha−1) and double doses (50 g a.i. ha−1) of application respectively. The dietary exposure of imidacloprid on capsicum fruit under both conditions exposed that hazard quotient (HQ) values obtained from the different treatment doses have not exceeded the upper limit of toxicity (HQ < 1) and imidacloprid residues in the fruits were found below the existing MRL (Maximum Residue Limit) values (0.5 mg/kg) at 3 days after its final applications. Thus, imidacloprid may be considered as the effective chemical management option against aphids in capsicum under polyhouse and open field having no harmful effect on human consumption.

Evaluating the Safety of Imidacloprid FS Seed Treatment Use in Potato Production: A Case Study from China.

This study evaluated the residue behavior and dissipation dynamics of a new imidacloprid FS 600 seed treatment in potato cultivation systems in Shandong and Jilin, China. Sensitive and accurate UPLC-MS/MS methods were established to quantify imidacloprid residues in potatoes, potato plants, and soil. Results showed that imidacloprid dissipation followed a first-order kinetic model, with half-lives ranging from 6.9 to 26.7 days in plants and 19.8 to 28.9 days in soil. At harvest, the highest average residues in potatoes and soil were 0.778 mg/kg and 0.149 mg/kg, respectively. The dietary risk assessment indicated a chronic risk quotient (CRQ) of 39.73% for adults, indicating minimal risk to human consumers, while the ecological risk quotient (ERQ) and ecotoxicity exposure ratio (TER) revealed low to moderate toxicity to earthworms, warranting caution in the use of this formulation. This research provides valuable data for assessing the safety of imidacloprid FS seed treatment in potato cultivation.

Dissipation and residues of imidacloprid in amaranth under greenhouse and open field cultivations

Despite the extensive exposure to imidacloprid residues in food plants, there has been little research on imidacloprid residues in amaranth. The dissipation trend and residue behavior of imidacloprid were evaluated to provide guidelines for imidacloprid application on amaranth under open field and greenhouse. The dissipation rate of imidacloprid in amaranth conformed to the first-order kinetic equation, and the half-lives of imidacloprid in amaranth ranged from 0.29 days in open field to 1.29 days in the greenhouse. After 7 and 14 days from the application of imidacloprid (pesticide dosage, 45 or 67.5 g a.i./ha), the amaranth under the open field and greenhouse growth could be consumed safely with average residues of 0.19 and 0.38 mg/kg, respectively. This result demonstrated that the cultivation has the dominant influence on imidacloprid residue, and the residue of imidacloprid in amaranth planting on open field was much lower than that in the greenhouse, indicating a significant difference in the pesticide residues between the two cultivations with a p-value less than 0.05.

Dissipation behavior and risk assessment of imidacloprid and its metabolites in apple from field to products

Pesticides play vital roles in controlling pests and boosting crop yields. Imidacloprid is widely used all over the world and may form in agricultural products. The presence of pesticide residues in apples raises serious health concerns. Understanding the residual fate of imidacloprid is critical for food safety and human health. In this study, the dissipation behavior, metabolism, household processing and risk assessment of imidacloprid and its metabolites in apple were investigated from filed to products. Field experiment results suggested that the half-lives of imidacloprid at 5 times the recommended dosage was 1.5 times that of the standard dosage. And the final residues of imidacloprid were less than the established maximum residue limits (MRLs). Clarification and simmering had little effect on the reduction the residues of imidacloprid and its metabolites. The calculated processing factors were lower than 1 for imidacloprid and its metabolites, implying that the residual ratios of imidacloprid and its metabolites in each steps of the food processing were reduced. The risk quotients were <1 for all Chinese people, indicating that acceptable risks associated with dietary exposure to imidacloprid in apple. However, the higher risks were observed in young people than adults, and females faced higher risks than males. Given high residue levels in pomace, imidacloprid and its metabolites should be further studied in commercial byproducts.

Regenerated SERS substrate based on Ag/AuNPs-TiO2-oxidized carbon cloth for detection of imidacloprid

Imidacloprid (IMI) are widely used in modern tea industry for pest control, but IMI residues pose a great threat to human health. Herein, we propose a regeneration metal-semiconductor SERS substrate for IMI detection. We fabricated the SERS sensor through the in-situ growth of a nano-heterostructure incorporating a semiconductor (TiO2) and plasmonic metals (Au, Ag) on oxidized carbon cloth (OCC). Leveraging the high-density hot spots, the formed Ag/AuNPs-TiO2-OCC substrate exhibits higher enhancement factors (1.92 × 108) and uniformity (RSD = 7.68%). As for the detection of IMI on the substrate, the limit of detection was lowered to 4.1 × 10−6 μg/mL. With a hydrophobic structure, the Ag/AuNPs-TiO2-OCC possessed excellent self-cleaning performance addressing the limitation of single-use associated with traditional SERS substrates, as well as the degradation capability of the substrate under ultraviolet (UV) light. Accordingly, Ag/AuNPs-TiO2-OCC showcases outstanding SERS sensing and regenerating properties, making it poised for extensive application in the field of food safety assurance.

A sensitive fluoroimmunoassay for quantitative detection of imidacloprid based on quantum dot-streptavidin conjugate

Imidacloprid (IMI), the most commonly used neonicotinoid, is widely present in both the environment and agro-products due to extensive and prolonged application, posing potential risks to ecological security and human health. This study introduced a sensitive and rapid fluorescence-linked immunosorbent assay, employing Quantum Dot-Streptavidin conjugate (QDs-SA-FLISA), for efficient monitoring of IMI residues in agro-products. Under optimized conditions, the QDs-SA-FLISA exhibited a half-maximal inhibition concentration (IC50) of 1.70 ng/mL and a limit of detection (LOD, IC20) of 0.5 ng/mL. Investigation into the sensitivity enhancement effect of the QDs-SA revealed that the sensitivity (IC50) of the QDs-SA-FLISA was 7.3 times higher than that of ELISA. The recoveries and relative standard deviation (RSD) ranged from 81.7 to 118.1 % and 0.5–9.4 %, respectively, for IMI in brown rice, tomato and pear. There was no significant difference in IMI residues obtained between QDs-SA-FLISA and UHPLC-MS/MS. Thus, the QDs-SA-FLISA represents a reliable approach for the quantitative determination of IMI in agro-products.

Farm to fork strategy for evaluating the qualitative and quantitative health risks to the Nepalese population associated with pesticide residues in apple and banana

Studies of pesticide use on commercial fruits are limited in Nepal. We surveyed the experiences and opinions of banana farmers in Nepal and monitored pesticide residues in apples and bananas. We monitored the residual status and associated health risks of 51 multi-group pesticides using Liquid Chromatography Triple Quadrupole Mass Spectrometry. Apple and banana samples were collected from different districts, farms, markets, and seller categories (our farm to fork survey). We found a significant bivariate positive correlation between farmers’ knowledge of pesticide negative effects and safety-promoting behavior among farmers. Residues of tebuconazole, difenoconazole, propargite and imidacloprid were most frequently detected. Of all the detected pesticides, propargite showed the highest concentration in apples, exceeding regulatory maximum residue limits (MRLs) in 24% of the samples. Epoxiconazole, tebuconazole, imidacloprid, quinalphos, fenpropathrin and bifenthrin in apples, and metalaxyl and imidacloprid in bananas also crossed their MRLs. Dietary exposure to pesticides among children and adults was estimated based on a hazard quotient and hazard index by using lower-bound and upper-bound approaches. Our results indicated that children consuming apples with residues of propargite are exposed to the greatest pesticide hazard.

Metal-organic frameworks as sensitisers for potentiometric sensors

As an example for a metal-organic framework (MOF) sorbent acting as sensitiser in a potentiometric sensor, we introduce the metal–organic framework (MOF) UiO-66-NH2 into a bridged extended-gate field effect transistor (EGFET) design. The sensitised EGFET detects residue of the insecticide imidacloprid with a limit of detection more than 3 orders of magnitude smaller than the EU ‘Maximum Residue Limit’ (MRL) for imidacloprid. This allows decisions on MRL compliance of water at a much lower experimental footprint than with chromatographic methods. To apply the sensor to food samples, we account for possible interference from legitimate food ingredients. Interference is small or moderate for fruit juices, moderate for ‘red’ juice (containing anthocyanin dyes), and small for others. Interference is strong for tea, probably from caffeine. We propose a test protocol to make ‘accept/reject’ decisions with respect to imidacloprid residue even in the presence of small or moderate interference. The present agar-bridged EGFET design enables the wider use of MOF sorbents in potentiometric sensors.

Development of Green and Facile Sample Preparation Method for Determination of Seven Neonicotinoids in Fresh Vegetables, and Dissipation and Risk Assessment of Imidacloprid and Dinotefuran.

A facile procedure for extracting and determining seven neonicotinoids was developed. Water was the only extraction solvent without phase separation and cleanup steps. The method was validated according to European Union standards, and the values obtained were compared with the criteria. The accuracy values were between 99.8% (thiamethoxam) and 106.8% (clothianidin) at the spiking levels of 0.01, 0.1, and 1 mg/kg in the tested matrices. The precision as pooled RSD values was ≤6.1% (intra-day) and ≤6.9% (inter-day). The limit of quantification was set and tested at 0.01 mg/kg. The matrix effect was evaluated, and all matrices had a suppressive effect. The matrix of the cucumber was the most effective, with -20.9% for dinotefuran and an average of -9.8% for all compounds, while the tomato matrix had the slightest effect. Real marketed samples were analyzed using the developed and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methods; the results were not significantly different. A supervised field trial was conducted in the open field to study the dissipation patterns of imidacloprid and dinotefuran in tomatoes. The dissipation of both compounds followed first-order kinetics. The half-life (T½) values were 3.4 and 2.5 days, with dissipation rates k of 0.2013 and 0.2781 days, respectively. Following the EU-MRL database, the calculated pre-harvest interval (PHI) values were 7 and 14 days for imidacloprid and dinotefuran, respectively, and 3 days for both compounds following Codex Alimentarius regulations. The risk of imidacloprid and dinotefuran residues was estimated from chronic and acute perspectives. The risk factors of dinotefuran were lower than those of imidacloprid. Nonetheless, the highest expected residues of both compounds were below the tolerance limits.

Oxytetracycline Increases the Residual Risk of Imidacloprid in Radish (Raphanus sativus) and Disturbs the Plant-Rhizosphere Microbiome Holobiont Homeostasis.

Antibiotics can be accidentally introduced into farmland by wastewater irrigation, and the environmental effects are still unclear. In this study, the effects of oxytetracycline on the residue of imidacloprid in soil and radishes were investigated. Besides, the rhizosphere microbiome and radish metabolome were analyzed. It showed that the persistence of imidacloprid in soil was unchanged, but the content of olefin-imidacloprid was increased by oxytetracycline. The residue of imidacloprid in radishes was increased by nearly 1.5 times, and the hazard index of imidacloprid was significantly raised by 1.5-4 times. Oxytetracycline remodeled the rhizosphere microbiome, including Actinobe, Elusimic, and Firmicutes, and influenced the metabolome of radishes. Especially, some amino acid metabolic pathways in radish were downregulated, which might be involved in imidacloprid degradation. It can be assumed that oxytetracycline increased the imidacloprid residue in radish through disturbing the plant-rhizosphere microbiome holobiont and, thus, increased the pesticide dietary risk.

Dissipation and residues of 18% imidacloprid + buprofezin SC in citrus and soil

ABSTRACT Eighteen per cent imidacloprid + buprofezin suspension concentrate (SC) has been registered for the control of scale insect on citrus trees, but the dissipation of this pesticide mixture on citrus is still a research blank area. In order to fill the gaps and ensure the safe application of mixture formulation, field trials were conducted in Guangdong, Guangxi and Hunan Provinces of China for 2 consecutive years to evaluate the final residue and dissipation dynamic of imidacloprid and buprofezin in citrus and soil. Both pesticides were extracted by the modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method, while imidacloprid was determined by high-performance liquid chromatography (HPLC) and buprofezin was determined by gas chromatography (GC). The established method achieved a good linearity relationship (r = 0.9999) and high sensitivity, the LODs (limit of detection) of imidacloprid and buprofezin were 0.002–0.013 mg/kg, which can fully meet the need for pesticide residue detection. Average recoveries (AR) of imidacloprid and buprofezin in citrus and soil were 77.64–105.95% and 85.89–102.28%, with relative standard deviations (RSD) of 3.06–7.91% and 3.29–7.25%, respectively. Results of field trials showed that the half-lives of imidacloprid in citrus and soil were 1.90–3.97 and 2.52–16.98 days, and that of buprofezin were 1.69–9.14 and 1.21–8.56 days. On the 21st day after the last application, final residues of imidacloprid and buprofezin in all samples were below their maximum residue limits (MRL) stipulated by China, indicating that it is safe to apply 18% imidacloprid + buprofezin SC on citrus trees. In conclusion, 18% imidacloprid and buprofezin SC was recommended to be spared twice at the intervals of 7 days with dosages of 180 or 270 mg/L, and the citrus fruit can be harvested safely 21 days after the last application. These results help ensure the safe application of imidacloprid and buprofezin in citrus orchards.

Non-target influence of imidacloprid residues on grape global metabolome and berry quality with the identification of metabolite biomarkers.

This paper illustrates the non-target impact of imidacloprid (IM) residues on the grape global metabolome and biomarker identification with high-resolution mass spectrometry. IM was applied at the recommended dose (SD), and ten times SD (10 RD). The global metabolome analysis revealed that 21 metabolites were up- and down-regulated with IM SD treatment. In 10 RD, 9 metabolites were upregulated, and 28 were downregulated. Pathway enrichment analysis revealed the primary and secondary pathway disruption in grapes. Berry quality was affected with decrease in flavonoids by 32.97% in 10 RD; phenols were reduced by 53.93 in SD, 50.8% in 10 RD. The non-target and target study revealed the degradation of IM in grapes to desnitro-IM and IM-urea which were identified as a potential biomarker for IM residues in grapes, which would benefit the authentication of organic product. Overall, imidacloprid showed a significant impact on the grape metabolome and quality.

Effect of the presence of carbendazim on imidacloprid degradation in a biological organic mixture

ABSTRACT The biological organic mixture (BOM) is a major component of a biopurification system (BPS), which provides an ample substrate for many microbes. Fungi present in BOM predominantly degrade pesticides through co-metabolism. We assume that the application of fungicides could have an impact on the fungal growth as well as the depuration ability of the BPS. This study is conducted to evaluate the efficiency of BOM in degrading imidacloprid in the presence of carbendazim, a commonly used fungicide. Both pesticides degraded at a faster rate when treated separately with the BOM, but their half-lives increased when applied in combination. The applied quantity of carbendazim (100 times of field recommended dose) was degraded within 60 days of the experiment. Approximately 75% of applied imidacloprid was dissipated within first 15 days of the experiment. Although carbendazim degraded at a faster rate, it had a negative impact on imidacloprid degradation during the experiment. Imidacloprid residue did not produce a negative effect on carbendazim degradation. Microbial and major soil enzyme activities were suppressed when BOM was exposed to the combination of pesticides in comparison to their single applications. Application of carbendazim was lethal to fungal population and may be the reason behind the increased persistence of imidacloprid in BOM.

Non-target impact of imidacloprid residues on wine aroma characteristics assessed by GCxGC-TOF/MS analysis and its residual transformation in vinification by UHPLC-Orbitrap-MS analysis

Grapes are a commercially important fruit crop worldwide. The use of pesticides for the control of insects and diseases is prevalent in commercial vini-viticulture. However, pesticide residues are known to impact wine quality significantly. The impact of imidacloprid residues on wine flavor was assessed by GCxGC-ToF/MS. Imidacloprid was applied at the recommended dose (SD) and ten times SD (10RD). Substantial degradation of imidacloprid residues was recorded from grape to wine, with 5.79% to 8.95% transfer rates and processing factors ranging between 0.08 and 0.13. The degradation pathway of imidacloprid was established by UHPLC-Orbitrap-LC/MS in wine with its identified metabolites as 6-chloronicotinic acid, desnitro imidacloprid, and imidacloprid-urea. Imidacloprid residue impacted wine flavor compounds, acids, esters, and alcohols. Glycolysis, pyruvate, glyoxylate, and dicarboxylate were the most significantly affected pathways. Volatiles, viz., phenol 3-(trifluoromethyl), acetic acid hydroxy, and ethyl acetate, were identified as biomarkers for imidacloprid residues in wine.

Assessment of degradation mechanism of imidacloprid residues in grape rhizosphere soil by UHPLC-Orbitrap™-MS and its residual impact on soil enzyme activity.

Imidacloprid (IM) is a systemic insecticide persistent in the environment and possesses a negative impact on the non-targeted ecosystem. The objective of the present study was to evaluate the dissipation and degradation mechanism of IM residues in grape rhizosphere soil and to investigate its residual effect on soil enzyme activity at different IM spiking levels. The half-life of IM residue in soil was 27, 36, and 43.5days at a spiking level of 1, 10, and 50mgkg-1, respectively following a bi-phasic first + first-order dissipation kinetics. UHPLC-Orbitrap™-MS analysis by targeted metabolomics approach revealed that IM metabolites such as IM-amine analogue, guanidine (reduction), 5-hydroxy IM (hydroxylation), IM-Urea (oxidation), reduced NO analogue of IM (oxidation), and olefin of guanidine IM (dehydrogenation) were identified and proposed the degradation mechanism in grape rhizosphere soil. Toxicity of IM residues on five extracellular enzymes, viz., dehydrogenase, acid phosphatase, alkaline phosphatase, β-glucosidase, and urease revealed that activity of dehydrogenase, acid phosphatase, and alkaline phosphatase remained unaffected at 60th day of sampling. The β-glucosidase and urease were negatively affected throughout the incubation period indicating the influence of IM residues on carbon and nitrogen mineralization in soil. Thus, long-term exposure of IM to grape rhizosphere through soil drenching could affect soil enzyme activity which has a negative effect on the soil nutrient cycle and soil microbiome.

Topical and field‐tested residual effects of globally used insecticides on the parasitoid Tamarixia radiata released against the Asian citrus psyllid, Diaphorina citri

AbstractTamarixia radiata (Waterston) (Hymenoptera: Eulophidae) is the key parasitoid of the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), in several citrus‐producing regions of the world. Chemical control is common to suppress ACP. Insecticides from globally used classes of insecticides for controlling ACP were tested on its primary parasitoid, T. radiata. Evaluations included dose–response of dimethoate, fenpropathrin, and imidacloprid in a topical application and lethal and sublethal effects from residues of imidacloprid, fenpropathrin, horticultural mineral oil (HMO), pyrethrin, and spirotetramat at 1, 3, and 7 days after application (DAA) of sprays on citrus trees in the orchard. The parasitism potential of the females that survived insecticide exposure was evaluated on untreated nymphs of ACP developing on citrus shoots and untreated parasitoid females were evaluated on nymphs treated with insecticides. In the topical application, imidacloprid was 8× more toxic to T. radiata than dimethoate and fenpropathrin. The lethal effect of the residues from imidacloprid and fenpropathrin sprays was more detrimental than other insecticides. Parasitoid mortality from 1‐ to 3‐day‐old residues averaged 90–96% for imidacloprid, 83–94% for fenpropathrin, 38–77% for pyrethrin, 43–44% for HMO, and 17–33% for spirotetramat. Parasitism by females that survived insecticide exposure was reduced by 71–88% from fenpropathrin, 28–59% from pyrethrin, 31–55% from imidacloprid, 44–4% from spirotetramat, and 39–11% from HMO compared to untreated females. The lethal and sublethal effects of all insecticides on T. radiata were significantly reduced at 7 DAA, suggesting a lower impact on its establishment and performance if releases are made after a week from spray application.

Monitoring of imidacloprid residues in fresh fruits and vegetables from the central parts of Jordan

Imidacloprid pesticide is widely utilized in agriculture due to its effectiveness in controlling a broad spectrum of insect pests. However, its usage has raised concerns about potential environmental impacts, and requires careful monitoring and responsible application to ensure sustainable agricultural practices. Thus, Gas chromatography-mass spectrometry (GC-MS) was utilized to analyze imidacloprid in 300 vegetable and fruit samples obtained from 15 major wholesalers in four regions of Amman, Jordan's capital city. Among the examined samples, 39.7 % were found to be contaminated with imidacloprid residues. Imidacloprid levels in different edible fruits and vegetables ranged from less than the Limit of Quantification (LOQ) to 0.40 mg kg−1. Significantly, eggplant and apples exhibited the highest average values (0.40 and 0.25 mg kg−1, respectively). Lower levels were detected in bananas (0.04 mg kg−1), potatoes (0.05 mg kg−1), grapes (0.07 mg kg−1), and cabbage (0.07 mg kg−1). Imidacloprid was below the method detection limit (BD) in samples of okra, peaches, apricots, and carrots. Overall, 25 samples (8.3 %) exceeded the Codex maximum residue limit (MRL) for imidacloprid. Moreover, 8 out of the 300 samples (2.7 %) exceeded the MRL established by the Pest Management Regulatory Agency (PMRA). Notably, the fruits of eggplant and apple contained the highest residual levels (1.30 and 0.83 mg kg−1, respectively), markedly exceeding the CODEX and PMRA MRLs. Additionally, the maximum detected imidacloprid residue concentration in bananas (0.25 mg kg−1) was 500 % higher than the CODEX MRLs. The estimated average daily intake (EDI) of the Amman population varied from 0.00 to 0.144 μg kg−1 body weight day−1 across various products. The hazard index (HI) for imidacloprid ranged from 0.00 to 0.24, all of which were below unity in all samples (<1). In conclusion, this investigation reveals low HI levels of imidacloprid residues in commonly consumed fruits and vegetables. However, the significant presence of imidacloprid residues in some samples highlights the urgent need for comprehensive measures to limit potential health hazards to consumers.

Biodegradation of Imidacloprid by the Local Isolate Rhizobium pusense

Imidacloprid is systemic insecticide (1-[(6-chloro-3-pyridinyl) methyl]-N-nitro-2-imidazolidinimine) and the world’s most widely used has significant efficacy against a broad variety of pests and a unique mode of action by using it spreader and irrigation. The persistence of this pesticide in the soil means that it causes environmental damage that must be cleaned up. In this study collected and identified the best bacteria isolate that breakdown imidacloprid from the Plant Protection Director in Baghdad, which has been using neonicotinoid pesticides for years in their own greenhouse for pest control. Using high-performance liquid chromatography HPLC to measuring the residual concentrations of imidacloprid in MSM media at a concentration of 25 mg/L for 21 days to know the best degrading bacterial isolate for imidacloprid. The best bacterial isolate No.43 was able to degrade 50.2% for 21 days of imidacloprid which was identified as Rhizobium pusense according to morphological, cultural and biochemical tests. Moreover, genetic analysis for the 16S rRNA gene and given a new accession number (OP218458.1.) in the GenBank of NCBI. It could be concluded, from this study that the soil previously contaminated for long periods of time with imidacloprid can be treated by degrading the imidacloprid residues in it by isolated bacteria Rhizobium pusense.

Bioremediation of Imidacloprid by the Local Isolate Psychrobacter celer

Pesticide biodegradation can be accomplished by the technique of bioremediation, which makes use of microorganisms’ ability to degrade pesticide residues. This study aimed to separate and identify imidacloprid-biodegradable from botanical fields soil of greenhouses in the Plant Protection Directorate /Ministry of Agriculture in Baghdad, which has been using imidacloprid pesticides for many years. Using high-performance liquid chromatography, residual imidacloprid concentrations in MSM medium at a concentration of 25 mg/L after 21 days were measured to identify the best degrading bacterial isolates. Isolate No.37 the best bacterial isolate was able to degrade 63% of imidacloprid. was identified as Psychrobacter celer according to morphological, cultural and biochemical tests. Moreover, genetic analysis for the 16S rRNA gene and given a new accession number (OP672320.1) in the GenBank of NCBI, from this study that the soil previously contaminated for long periods of time with imidacloprid can be treated by degrading the imidacloprid residues in it by isolated bacteria Psychrobacter celer.

Dissipation kinetics, decontamination, consumer risk assessment and monitoring of flonicamid and imidacloprid residues in capsicum under open field and polyhouse condition.

Liquid chromatography mass spectrometry (LC-MS)-based detection of flonicamid, imidacloprid and 6-chloronicotinic acid residues was validated and analysed in capsicum fruit, processed products and soil. The standard concentrations (0.0025 to 0.25 μg mL-1) of insecticides had a good linear curve (r2>0.99). Limit of detection and limit of quantification values were 0.0025 and 0.01 mg kg-1, respectively. The accuracy (80.53 to 100.33 %) of capsicum matrices and soil (89.41 to 100.52 %) and precision (RSD <10%) were established. Dissipation of imidacloprid (20 and 40 g a.i. ha-1) and flonicamid (75 and 150 g a.i. ha-1) at single (X) and double dose (2X) was studied under open field and polyhouse conditions. Under open field conditions, the flonicamid and imidacloprid residues persisted with half-life of 1.98, 2.90 days (X) and 2.80, 3.14 (2X) days, respectively. While under polyhouse conditions, the flonicamid and imidacloprid residues persisted with a half-life of 2.84, 3.66 (X) and 3.24, 3.97 (2X) days, respectively. The metabolite, 6-CNA, was not detected in any samples under open field and polyhouse condition. Among decontamination treatments, cooking in boiling water for 10 minutes reduced 78 to 81.60 percent of imidacloprid and flonicamid residues in both doses. The estimated dietary risk assessment of imidacloprid and flonicamid residues (RQ <1) indicated that the risk is within the acceptable limit. In farmgate capsicum samples, residues of flonicamid (7 samples) and imidacloprid (11 samples) were detected. Market samples of capsicum products (powder, flakes and sauce) were not detected with residues of selected insecticides.