Regional selection of insecticides and fungal biopesticides to control aphids and thrips and improve the forage quality of alfalfa crops

The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa(aphids and thrips)were compared in three sites across China’s alfalfa belt.In addition,the persistence of the residues of chemical insecticides in alfalfa and their influence on the quality of alfalfa hay were examined.Efficacy varied among the different biological and chemical insecticides.The chemical insecticides were significantly more effective than biopesticides in a short time-frame.The efficacy period of biopesticides was significantly longer than that of chemical insecticides,and the corrected mortality rate of aphids in all regions was above 50%at 14 days after application.The analysis of pesticide residues showed that the residual doses of all the pesticides were within the allowed ranges after the safe period.The acid detergent fiber and neutral detergent fiber contents in alfalfa hay were higher and the protein content was lower in chemical insecticide treatments than in biopesticide treatments in Hebei.The relative feeding value of alfalfa hay treated with Metarhizium anisopliae IPP330189 was the highest among the treatments.Compared with chemical insecticides,the yield of alfalfa hay was higher in the biopesticides treatments.Biopesticides show a stronger control effect on insect populations and also a better improvement in the quality of alfalfa hay than chemical insecticides.This study provides a basis for exploring and developing a comprehensive control regime for alfalfa insect pests in the different alfalfa-growing regions in China,and for reducing chemical insecticide usage and improving forage quality.

Determination of 14 Organophosphorus Pesticide Residues in Mutton by Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry(GPC-GC-MS)

[Objectives]This study was conducted to purify mutton samples by gel permeation chromatography(GPC).[Methods]Fourteen organophosphorus pesticide residues in samples were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS)in selective ion scanning mode(SIM).[Results]The organophosphorus pesticide standard solutions showed good linearity in the mass concentration range of 0.1-10.0μg/ml with correlation coefficients(r)not lower than 0.999,and the detection limits(S=3 N)ranged from 0.01 to 0.05 mg/kg.The average recovery values were in the range of 80.2%-99.7%,with relative standard deviations(RSDs,n=3)in the range of 1.8%-6.3%,at the addition levels of 0.5,1.0 and 2.0 mg/kg.[Conclusions]The method is simple,sensitive and accurate,and can be used for the determination of organophosphorus pesticide residues in mutton.

Research Progress of QuEChERS Pretreatment Technique in the Detection of Multiple Pesticide Residues

The QuEChERS extraction technique is a pretreatment technique that has been rapidly applied in recent years and is widely used in the field of pesticide residues with many advantages. This technique is based on solid phase extraction (SPE), which uses the interaction between adsorbent and impurities in the matrix to achieve the purpose of purification. The method has easier operation and better purification effect than SPE. In this paper, the research progress of the QuEChERS technique in pesticide residue detection in different fields in recent years and its future development were reviewed, hoping to provide reference for further development and utilization of the QuEChERS technique in pesticide residue detection in the future.

Research Progress on Detection Techniques of Fungicide Residues in Chinese Chives

Chinese chive is a kind of medicinal and edible plant,with many diseases,and chemical fungicides are usually used for control.In order to find out the risk of pesticide residues in Chinese chives,this paper summarized relevant literatures published in recent years,and sorted out and analyzed the types of pesticides used and detection techniques of common diseases in Chinese chives.

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides （OCPs） were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX （DDD, DDE and DDT） had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p＇-（DDD＋DDE）/DDT in soils under three land usages were： paddy field 〉 tree land 〉 fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p＇-（DDD＋DDE）/DDT 〉1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.

A novel thermal biosensor based on enzyme reaction for pesticides measurement

A novel thermal biosensor based on enzyme reaction for pesticides detection has been developed. This biosensor is a flow injection analysis system and consists of two channels with enzyme reaction column and identical reference column, which is set for eliminating the unspecific heat. The enzyme reaction takes place in the enzyme reaction column at a constant temperature(40℃) realized by a thermoelectric thermostat. Thermosensor based on the thermoelectric module containing 127 serial BiTe-thermocouples is used to monitor the temperature difference between two effluents from enzyme reaction column and reference column. The ability of this biosensor to detect pesticides is demonstrated by the decreased degree of the hydrolytic heat in two types of thermosensor mode. The hydrolytic reaction is inhibited by 36% at 1 mg/L DDVP and 50 % at 10 mg/L DDVP when cell-typed thermosensor is used. The percent inhibition is 30% at 1 mg/L DDVP and 42% at 10 mg/L DDVP in tube-typed thermosensor mode. The detection for real sample shows that this biosensor can be used for detection of organophosphate pesticides residue.

Matrix Effects of Fourteen Organophosphorus Pesticides Residues in Nine Kinds of Vegetable Matrices

The matrix effects of 14 organophosphorus pesticides in 9 kinds of vegetables matrices were preliminarily studied by gas chromatography/flame photomet- ric detection（FPD） in the paper. The matrix effects of 14 organophosphoms pesticides in 9 kinds of vegetable matrices at 0.05, 0.1 and 0.2 mg/L were compared, respectively. The results showed that matrix enhancement effect and matrix attenuation effect existed in all cases, while matrix effects did not have strong correlation with concentrations of pesticides, but were related to species of vegetables and structure and polarity of pesticides.

Determination of Pesticides Residues in Some Fruits and Vegetables Imported to Iraq

A study was carried out in the laboratories of the National Center for Pesticides Control/State Board for Plant Protection / Ministry of Agriculture in 2010-2011. The aim was to determine the residues of some pesticides in fruits and vegetables imported to Iraq from neighboring countries （Jordan, Syria, Turkey and Iran）. Two types of fruits （apples and oranges） and two types of vegetables （tomatoes and cucumber） were selected for the purpose of this study. These fruits and vegetables are the most agricultural products imported for human consumption in Iraq. Samples were taken from different border points and from local markets. Extraction, clean up and analysis were then processed. The results indicated the presence of small amounts of residues of certain pesticides such as Deltamethrin and Abamectin and Thiamethoxam in some samples. However, these amounts were less than the limit allowed internationally. No indication was observed for the presence of other pesticides residues such as Bifenthrin Trticonazol and Imidacloprid ... etc. in the samples analyzed. Therefore, there is a need to continuity of inspection on pesticides residues in agricultural products imported to Iraq in order to prevent the entry of contaminating materials and secure human safety.

Assessment of the Pesticides Utilization and the Pesticide Residues Presence in Fresh and Tomato Products for the Tomato Supply Chain in Rwanda

Pesticide residues are either natural or synthetic and are found in most edible products such as fresh fruits, vegetables, meat and other processed products. Excess of these pesticides’ residues is unsafe for consumption due to regulatory measures. Thus, it is beneficial to assess the level of residues of pesticides in the food diet in order to improve the standard of living of the population. This study intends to assess the pesticide usage and residue levels of selected pesticides in fresh tomatoes in the supply chain of Rwanda. The results of the study confirm that there are around 10 brands of pesticides used in Rwanda. 58.97% of the surveyed people around the country are males and 71.79% of farmers apply rockets as the main pesticide. More than 22% of surveyed farmers affirmed to consume the raw or/and unwashed tomatoes. This study revealed that the residues of the active ingredients contained in the pesticides are accumulated in unwashed tomatoes and the quantity of such residues is shown in this study. Deltamethrin was 0.64 ± 0. 009 mg·kg?1 in tomatoes collected in Rusizi district, cypermethrin 1.1435 ± 0. 0375 mg·kg?1 in tomatoes collected from Gisagara District, mancozeb residues was 0.620 ± 0.000 mg·kg?1 in tomatoes collected from Rusizi district. The results of the study also show that pesticide residues are not found in the washed tomatoes. Therefore, the detection of pesticide residues in unwashed tomatoes in some samples indicates the malpractice of residues among farmers in Rwanda. Also, consumers eating the unwashed fresh tomatoes are recommended to wash the tomatoes before use.

Rapid screening of 420 pesticide residues in fruits and vegetables using ultra high performance liquid chromatography combined with quadrupole-time of flight mass spectrometry

A new method for screening and identification 420 pesticide residues in fruits and vegetables by ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry(UPLC-Q-TOF/MS)were developed.The samples were extracted with acetonitrile/acetic acid(99:1,V/V),and clean-up by SinChERS-Nano(single-step,cheap,effective,rugged,safe,nano)column,determined by UPLC-Q-TOF/MS.The accurate mass database and MS/MS database which contains 420 pesticides were established,the automatic retrieval of detection results was carried on according to the accurate mass,retention time,isotope ratio,ion fragment information,and so on.Method verification was performed on leeks samples.The results showed that 420 pesticides had good linearity in the range of 0.1-100μg/L,and the correlation coeffificients(R2)was greater than 0.990.The limits of detections(LODs)and limits of quantifications(LOQs)of 420 pesticides were in range of 0.05-2.0 and 0.1-5.0μg/L,respectively.The average spike recoveries at 3 levels were 70.1%to 119.7%,and the relative standard deviations(RSD)were lower than 20%(n=6).With this method,a survey of pesticide residues was conducted for 110 samples of 10 different fruits and vegetables,which provided scientific data for ensuring pesticide residue safety of the fruits and vegetables consumed daily by the public.This method was simple,sensitive and accurate,and could be used for rapid screening of 420 pesticide residues in fruits and vegetables.

Application of Mass Spectrometry (MS)-coupled Techniques in Pesticide Residue Detection

Pesticide residue detection is an important work to ensure the quality safety of agricultural products.In the process of agricultural production,in order to prevent and control agricultural diseases and pests,a certain amount of pesticides need to be used.However,if pesticides are used excessively,there will be certain pesticide residues in crops and related products.Therefore,it is necessary to do a good job in pesticide residue detection.The gas chromatography-mass spectrometry(GC-MS)and liquid chromatography-mass spectrometry(LC-MS)detection methods have good results and can effectively detect pesticide residues in related products.This paper reviewed and analyzed the application of GC-MS and LC-MS in pesticide residue detection,and proposed optimization measures based on practical experience,hoping to provide reference for relevant scholars.

Detection and Analysis of Pesticide Residues in Chinese Chives and Risk Assessment of Dietary Intake

[Objectives]This study was conducted to understand the status of pesticide residues and dietary intake risk of Chinese chives in Tangshan area. [Methods] Sixty eight kinds of pesticide residues in 415 Chinese chive samples collected from Tangshan area were qualitatively and quantitatively determined by high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) and gas chromatography(GC) in 2020. [Results] The results showed that 41 kinds of pesticide residues were detected in the 415 Chinese chive samples, and the detection rate was 69.4%(288/415), and there was a combination of pesticides in many samples. According to the National Food Safety Standard―Maximum Residue Limits of Pesticides in Food(GB 2763-2019), the residues of 12 pesticides exceeded the maximum residue limits(MRLs), and the unqualified rate was 38.07%(158/415). The highest detection rate of clothianidin was 41.20%(171/415), but there was no MRL in GB 2763-2019. The next was procymidone, the detection rate of which was 35.42%(147/415), and the over-standard rate was 30.12%(125/415). Forbidden and restricted pesticides were detected in some samples. According to the dietary exposure risk assessment, the NEDI/ADI values were all less than 1 and the intake risk was within acceptable range. In Tangshan area, the types of pesticides used in Chinese chive production are complex, and there are risks of multi-residue pollution and use of banned and restricted pesticides and unregistered pesticides. It is suggested that routine monitoring of pesticide residues and management of pesticide use should be strengthened to ensure the quality and safety of agricultural products. [Conclusions] This study provides a theoretical basis for the safe production of Chinese chive and the standardized and rational use of pesticides.

A Rapid Determination of 30 Prohibited Pesticide Residues in Lycii Fructus by UPLC-MS/MS

Prohibited pesticide residues have become one of the main factors affecting the quality and safety of Lycii Fructus,However,rarely studies focus on the rapid determination of these residues.Here,a total of 30 kinds of prohibited pesticide residues were determined by ultra-performance liquid chromatography tandem triple quadrupole mass spectrometry(UPLC-MS/MS)in five different process ways.Pretreatment methods,chromatographic separation and detection conditions in mass spectrometry were all optimized accordingly.Among the five different pretreatment methods,the first and third solid phase extraction failed to provide high recoveries of sulfosulfuron compounds(both lower than 60%).Recovery of chlorphenamidine by the Quick Easy Cheap Effective Rugged and Safe multiresidue method(QuEChERS)was lower than 60%,which did not meet the requirements of trace determination.The concentrations of 30 prohibited pesticides residues treated by straightforward and solid phase extraction showed good linearity in their corresponding ranges,with correlation coefficients over 0.99.The average recoveries of straightforward ranged from 78.13%to 110.9%,while RSD ranged from 1.3%to 16.9%,albeit poor purification was observed.The recovery yield from solid phase extraction was between 67.75%and 103.08%with RSD value from 0.8%to 14.0%,which met the requirements of trace determination,this method has good precision and stability.These results could be employed to other Traditional Chinese Medicines(TCMs)in detecting prohibited pesticide residues.

Rapid Screening of Pesticide Residues in Strawberry Based on HPLC-QTOF/MS SWATH Acquisition Mode

[Objectives]The paper was to establish a rapid screening method of pesticide residues in strawberry based on HPLC-QTOF/MS SWATH acquisition mode.[Methods]The strawberry sample was extracted with acetonitrile,purified with anhydrous magnesium sulfate,sodium chloride and primary secondary amine(PSA)powder,and then loaded on the machine.The full information spectrum was collected by positive ion mode and screened by comparing with the spectrum library,and 20 kinds of pesticide residues were quantitatively analyzed.[Results]The detection limits of 20 pesticide residues were 0.0002-0.0100 mg/kg,and they showed good linearity in the range of 0.0005-0.1000μg/mL(R 2≥0.995).The recoveries ranged from 62.8%to 106.3%.[Conclusions]This method is rapid,simple,sensitive and non-targeted,and can be used for rapid screening of multiple pesticide residues in strawberry.

Pesticide Residue Content in Vegetable Bases of Lhasa City

[Objectives]To understand the quality safety of vegetables produced in vegetable planting bases around Lhasa City.[Methods]Four vegetable planting bases in the east,west,south,and north of Lhasa City were randomly selected for testing using rapid measuring instrument for agricultural residues and solid-phase microextraction-gas chromatography-mass spectrometer,with 120 vegetable samples selected.The testing samples included seven categories:green leafy vegetables,eggplants,melons,onions and garlic,root vegetables,beans,and fungi,totaling 29 types of vegetables.The samples were tested for 8 common prohibited and restricted pesticides in organic phosphorus and carbamate esters,including methamidophos,parathion,methyl parathion,monocrotophos,isocarbophos,methamidophos,aldicarb,and carbofuran.[Results]The pesticide inhibition rate of 6 kinds of vegetables detected by the rapid measuring instrument for agricultural residues was relatively high,with green leafy vegetables being the majority,reaching over 25%.By further establishing a solid-phase microextraction-gas chromatography-tandem mass spectrometry method,the accuracy of the data was verified experimentally.The experimental results indicated that the inhibition rate of vegetable samples in this experiment did not exceed 15%,and it was determined as a pollution-free vegetable.[Conclusions]According to the restriction standard of national pesticide use,the inhibition rate of vegetable samples was less than or equal to 40%,indicating that the quality of vegetables was qualified.

Multiple Pesticide Residues in Bananas Sold in Tangshan City and Dietary Risk Assessment

[Objectives]This study was conducted to investigate the pesticide residue status of bananas in Tangshan area and the dietary intake risk of consumers.[Methods]High-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)was applied to detect 70 pesticide residues in 191 batches of banana samples extracted from Tangshan area,and chronic and acute risk assessments were conducted.[Results]Among the 191 batches of bananas,172 batches of samples were detected to contain agrochemicals,with a detection rate of 90.05%.Seventeen agrochemicals were detected,accounting for 24.29%of the total agrochemicals tested.There was a phenomenon of multiple pesticide residues in a single sample,and high detection rates were found in carbendazim(49.21%),prochloraz(41.88%),pyraclostrobin(34.03%)and imidacloprid(30.37%).According to GB 2763-2021 National Food Safety Standards—Maximum Residue Limits for Pesticides in Food,the over-standard rate of imidacloprid was 17.8%;and the chronic and acute dietary risks of the 17 pesticide residues were all less than 100%.[Conclusions]The pesticide residues in bananas consumed by consumers on a daily basis do not pose unacceptable dietary risks.

Main Problems and Countermeasures of Chinese Chive Quality and Safety in China

In recent years,the problem of pesticide residues in Chinese chives has attracted widespread attention from society.This paper comprehensively analyzed the production and planting situation,quality and safety status and changes in pesticide standards of Chinese chives,and deeply discussed the main quality and safety problems of Chinese chives and their causes.On this basis,it was proposed to improve the quality and safety level of Chinese chives from three aspects:improving limit standards,promoting green production prevention and control techniques,and strengthening supervision on input products.

Effects of Househould Cleaning Methods on Carbendazim Residue in Apples

Carbendazim,belonging to fungicides,was commonly used for controlling crop diseases,resulting in frequent residues in fruits and vegetables.Washing was the initial step of household fruit processing for cleaning and reducing pollutant contents.However,the effect of washing on the removal of carbendazim in apples was not systemically studied.Thus,in this study,an analytical method was firstly established for the determination of carbendazim with great accuracy and precision through quick,simple,cheap,effective and safe(QuEChERS)method and ultra-performance liquid chromatography-fluorescence detection(UPLC-FLD).Then,the influencing factors were systematically researched to unveil their effects on the carbendazim residue in apples.The results indicated that water temperature,washing products and washing method could obviously affect the carbendazim content in apples.In addition,the best cleaning scheme for removal of carbendazim was soaking apples for 5 min in a cleaning solution,which was prepared by dissolving 8 g of commercial fruit washing soup with 500 ml of water at 45℃.Under this condition,the removal rate of carbendazim in the washing step reached 73.91%.This study will be helpful for providing guidance for household cleaning methods for controlling pesticide residues.

Determination of 2 Amides Pesticide Residues in Agricultural Products by Terahertz Time-domain Spectroscopy

[Objective] The aim was to explore the application of terahertz （THz） technique in pesticide recognition and residue determination. [Method] THz far-infrared spectral characteristics of 2 herbicides （butachlor and metolachlor） were measured by THz time-domain spectroscopy （THz-TDS） under conditions of room temperature and nitrogen,meanwhile their refractive index and absorption coefficient between 0.2 and 2.2 THz were calculated by using models based on Fresenl equations. [Result] The 2 pesticides both had a series of different characteristic absorption peaks between 0.2 and 2.2 THz,respectively. Their molecular structures were similar,but there were great difference in absorption and refractive index spectrum between them. [Conclusion] THz-TDS technique is feasible to detect pesticide residues,especially there is a greater advantage in identifying the structure of similar substances.

蔬菜农药多残留检测中主要干扰物的研究

The paper is to study the main co-extractions existing in multiresidue analysis of pesticides in vegetables.For this,extracted 10 vegetable and analyzed the extractions with GC-MS.Compared the spectra of those co-extractions in different vegetables,confirm the main co-extractions of vegetables.The result shows the co-extractions are same including pigment,phenols,fat acids,lipin and steroid.But the mass of those co-extractions in different vegetable is different.The study result is help for the development of pesticide residue method.