Abamectin Residues Research Articles

Risk Assessment of Selected Insecticides on Tamarixia triozae (Hymenoptera: Eulophidae), a Parasitoid of Bactericera cockerelli (Hemiptera: Trizoidae)

Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is an important parasitoid of the potato or tomato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Trizoidae), a serious pest of potato (Solanum tuberosum L.), tomato (Solanum lycopersicum L.), and other solanaceous vegetables in many countries. To produce a marketable crop, insecticides are required when B. cockerelli populations reach economically damaging levels. We evaluated 11 commonly used insecticides for their effects on T. triozae. Glass-surface residues of spinetoram, imidacloprid-cyfluthrin, abamectin, and tolfenpyrad caused 100% mortality of T. triozae in 72 h, and the leaf residue of spinetoram was extremely toxic to T. triozae adults; even 15-d-old residues caused 100% mortality. Cyantraniliprole, fenpyroximate, pymetrozine, spirotetramat, spiromesifen, and chenopodium oil did not cause significant mortality in either glass surface or leaf-residue bioassays. Ingestion of spinetoram, abamectin, and imidacloprid+cyfluthrin (Leverage) by the adults resulted in 100% mortality in 12 h, and tolfenpyrad, 75.0% mortality in 12 h; whereas chenopodium oil and pymetrozine showed moderate effects on adult survival. Ingestion of abamectin, imidacloprid-cyfluthrin, and spinetoram killed all adults in the first day of treatment, whereas female adults in the treatment of pymetrozine lived 80.8 d, which was similar to those in the control. Ingestion of abamectin, imidacloprid-cyfluthrin, chenopodium oil, and spinetoram killed all male adults in the first day, whereas ingestion of other insecticides did not cause significant mortality, but reduced percent parasitism. Abamectin, imidacloprid-cyfluthrin, and spinetoram had the most deleterious effects on T. triozae, and have the least potential for use in integrated control programs using this parasitoid.

Determination of Abamectin Residue in Paddy Rice by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

研究并构建了一种新型CdTe量子点＂开关＂,利用量子点荧光强度的变化进行痕量诺氟沙星的检测。考察了不同缓冲溶液,pH值,Co2＋浓度等因素对体系的影响。结果表明,在pH=10的硼砂缓冲液中,Co2＋能猝灭CdTe的荧光;体系中加入诺氟沙星后,CdTe的荧光得到恢复,并且量子点荧光的恢复强度与诺氟沙星的浓度与呈良好的线性关系。基于量子点＂开关＂技术,通过检测CdTe荧光恢复强度,建立了一种测定诺氟沙星的方法。方法的线性范围为0.8×10^-8～4.4×10^-7 mol/L;检出限为2.3×10^-9 mol/L。应用于实际样品的检测,RSD≤2.2%（n=6）,回收率为98.4%～102.1%,结果令人满意。

Determination of Abamectin Residue in Paddy Rice by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A new method for the confirmation and quantification of abamectin residues in paddy rice was established based on ultra performance liquid chromatography-tandem mass spectrometry.The matrix effects for the method were studied.Paddy soil,paddy hull,brown rice and rice straw were extracted with acetonitrile by an oscillator,and cleaned up by C18 SPE cartridge or florisil column.Paddy water was extracted with ethyl acetate by liquid-liquid partition,and cleaned up by C18 SPE cartridge.The detection was performed by tandem mass spectrometry with electrospray ionization in positive mode(ESI+).Average recoveries of paddy soil,paddy water and brown rice at three spiked levels(1.0,10.0 and 100 μg/kg,or μg/L) were found in the range of 84%-107% with RSD13.6%.Average recoveries of paddy hull and rice straw at two spiked levels(10.0 and 100 μg/kg) were found in the range of 90%-103% with RSD12.9%.Limits of detection(LODs)of abamectin in paddy soil,paddy water and brown rice were 0.3 μg/kg,which were lower than the maximum residue limit(MRL) established by the Japanese and the European legislation in rice(10 μg/kg).Limits of detection(LODs) of abamectin in paddy hull and rice straw were 3.0 μg/kg.A good linear relationship was obtained in the range of 2.0-100 μg/L with the correlation coefficient(r) over 0.999.

Multi‐residue analysis of pesticide residues in mangoes using solid‐phase microextraction coupled to liquid chromatography and UV–Vis detection

A sensitive and efficient solid-phase microextraction method, based on liquid chromatography and UV-Vis detection, was developed and validated as an alternative method for sample screening prior to LC-MS analysis. It enables the simultaneous determination of ten pesticides in mango fruits. The fiber used was polydimethylsiloxane while optimum SPME conditions employed have been developed and optimized in a previous work. The desorption process was performed in static mode, using acetonitrile as a solvent. The results indicate that the DI-SPME/HPLC/UV-Vis procedure resulted in good linear range, accuracy, precision and sensibility and is adequate for analyzing pesticide residues in mango fruits. The limits of detection (0.6-3.3 μg/kg) and quantification (2.0-10.0 μg/kg) were achieved with values lower than the maximum residue levels (MRLs) established by Brazilian legislation for all pesticides in this study. The average recovery rates obtained for each pesticide ranged from 71.6 to 104.3% at three fortification levels, with the relative standard deviation ranging from 4.3 to 18.6%. The proposed method was applied for the determination of the aforementioned compounds in commercial mango samples and residues of azoxystrobin, fenthion, permethrin, abamectin and bifenthrin were detected in the mango samples, although below the MRLs established by Brazilian legislation.

Toxicity of three insecticides to Lysiphlebus fabarum, a parasitoid of the black bean aphid, Aphis fabae.

The toxicity of three insecticides to Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae), a parasitoid of Aphis fabae Scopoli (Hemiptera: Aphididae), was investigated using IOBC/wprs protocols. Abamectin 1.8 EC, imidacloprid 350 SC, and pymetrozine 25 WP were tested under laboratory conditions at recommended field rates. Immature stages of the parasitoid were exposed to materials by briefly dipping mummified aphids into insecticide solutions/suspensions or water (controls). Abamectin, imidacloprid, and pymetrozine caused 44.8, 58.5, and 14.5% mortality of mummies, respectively. Insecticides were also applied to broad bean foliage until run-off using a hand sprayer and the contact toxicity of residues was investigated after 1, 5, 16 and 30 day periods of outdoor weathering by caging adult wasps on treated plants for 24 h. One day-old residues of abamectin, imidacloprid, and pymetrozine produced 52.5, 90.0 and 57.0% mortality, respectively, and 5 day-old residues produced 28.1, 77.0 and 18.6% mortality. Sixteen day-old residues produced 8.8, 22.4 and 13.6% mortality, whereas 30 day-old residues produced 0.0, 3.2 and 1.1% mortality, respectively. On the basis of these results, abamectin and pymetrozine were classified as short-lived compounds (Class A) and imidacloprid as a slightly persistent compound (Class B).

Harvest Time Residues of Abamectin 1.9 EC in Cotton Seed, Lint and Oil

Harvest time residues of abamectin 1.9 EC after four applications at 14 days interval on cotton @ 10.8, 14.5, 18.5, 22.5 and 29.0 g a.i.ha -1 were determined in seed, lint and oil using high performance liquid chromatography (HPLC) equipped with F-1050 fluorescence detector. The interval between the last spray and first harvest was 37 and 34 days in the first and second field experiments, respectively. The harvest time residues of abamectin were at below detectable level (BDL) in cotton seed, lint and oil sample at all the concentrations tested.

A Fast, Simple, and Reliable High-Performance Liquid Chromatography (HPLC) Method for Determining Abamectin Residues in Vegetables and Fruits

This paper describes a simplified high-performance liquid chromatography method without clean-up step for the determination of abamectin residue in non-fatty vegetables and fruits. The abamectin residues were extracted efficiently with acetonitrile assisting by ultrasound and then directly derivatized without requiring the clean-up step. Results showed that the developed method has good sensitivity and selectivity for determining the abamectin residues in vegetables and fruits. Limits of detection and limits of quantification were 0.0005 and 0.002 μg/g, respectively. The recoveries ranged from 83.2% to 123.7% with satisfactory precision (RSD < 16.7%) and bias (−16.8 ∼ 23.7%). The proposed method was successfully applied to analyze the real commercial samples.

Toxicity of abamectin to the terrestrial isopod Porcellio scaber (Isopoda, Crustacea)

To determine effects of the antiparasitic veterinary drug abamectin on the isopod Porcellio scaber, animals were exposed for 21 days to Lufa 2.2 soil spiked at concentrations of 3-300 mg/kg dry soil. After exposure, abamectin residues in the isopods were analysed using a novel analytical method. Toxicity was evaluated on different levels of biological organisation: biochemical, cellular and the individual organism. Measurements included glutathione S-transferase (GST) activity and stability of cell membranes in the digestive gland, animal mass gain or loss, food consumption, behaviour and mortality. LC50 for the effect of abamectin on survival of P. scaber was 71 mg/kg dry soil. The most obvious sublethal effects were reduced food consumption and decreased body mass (NOEC 3 mg/kg dry soil). Additionally, loss of digging activity and reduced GST activity (NOEC 30 mg/kg dry soil) and cell membrane destabilization (NOEC 10 mg/kg dry soil) were recorded. Abamectin only slightly accumulated in the isopods, with bioaccumulation factors always being <0.1. Based on these results and current information on environmental levels of abamectin, it is not likely that isopods will be affected by abamectin, but further studies with exposure through faeces are recommended.

Detection of trace amounts of abamectin used as an antiparasitic agent in fallow deer tissues

A sensitive and reliable method for the determination of trace amounts of abamectin in muscles, kidneys and fat tissue of fallow deer is presented. Abamectin was extracted from the tissues with acetonitrile and the extract was cleaned up on a C8 solid-phase extraction cartridge. Abamectin residue was derivatised with trifluoroacetic acid anhydride and 1-methylimidazole, and determined using reversed-phase high-performance liquid chromatography under isocratic conditions and fluorescence detection. The recoveries of the method were high and consistent, ranging from 78% to 90%. The limit of detection of the method was below 1 microg/kg when analysing muscle, kidney and fat tissue. Matrix-matched calibration was used in order to obtain accurate values and to avoid matrix interference.

Determination of Abamectin Residues in Avocados by Microwave-Assisted Extraction and HPLC with Fluorescence Detection

In this article a new analytical method for the confirmation and quantification of abamectin residues in avocados is described. The method allows a fast analysis of abamectin homologues using microwave assisted extraction (MAE), solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) with fluorescence (FL) detection using trifluoroacetic anhydride (TFAA) and N-methylimidazole (NMIM) as derivatizing agents. The mobile phase consisted of water, methanol and acetonitrile (5:47.5:47.5 v/v/v) and was pumped at a rate of 1.1 mL min−1 (isocratic elution). Homogenized avocado samples were extracted once with 20 mL acetonitrile:water 4:1 (v/v) in a microwave oven for 26 min at 700 W with a maximum temperature of 80 °C. MAE operational parameters were optimized by means of an experimental design. Extracts were cleaned using C18 SPE cartridges. Average recoveries of the method at four spiked levels (0.005, 0.01, 0.10 and 1.0 mg kg−1) were found to be in the range 90–100% with good precision (RSD < 12%). The limits of detection (LODs) and quantification (LOQs) of the whole method were 0.001 and 0.003 mg kg−1, respectively, which are lower than the maximum residue limit (MRL) established by the Spanish and the European legislation in avocados (0.01 mg kg−1). Several avocado samples previously treated with the pesticide were also analyzed.

Analysis of abamectin residues in avocados by high-performance liquid chromatography with fluorescence detection

In this work an analytical method for the determination of abamectin residues in avocados is developed using high-performance liquid chromatography (HPLC) with fluorescence (FL) detection. A pre-column derivatization with trifluoroacetic anhydride (TFAA) and N-methylimidazole (NMIM) was carried out. The mobile phase consisted of water, methanol and acetonitrile (5:47.5:47.5 v/v/v) and was pumped at a rate of 1 mL/min (isocratic elution). The fluorescence detector was set at an excitation wavelength of 365 nm and an emission wavelength of 470 nm. Homogenized avocado samples were extracted twice with acetonitrile:water 8:2 (v/v) and cleaned using C 18 solid-phase extraction (SPE) cartridges. Recovery values were in the range 87–98% with RSD values lower than 13%. The limits of detection (LODs) and quantification (LOQs) of the whole method were 0.001 and 0.003 mg/kg, respectively. These values are lower than the maximum residue limit (MRL) established by the European Union (EU) and the Spanish legislation in avocado samples.

Determination of Abamectin Residue in Paprika by High-Performance Liquid Chromatography

Reversed-phase high-performance liquid chromatography (HPLC) techniques were developed to quantify abamectin (ABM) in paprika ( Capsicum annum ). Separation was achieved on a C 18 ODS column with a mobile phase of acetonitrile/water (96/4 v/v) mixture in an isocratic elution at the flow rate of 1.2 , ,, , mL/min for avermectins (AVMs). The retention times were 8.0 and 9.7mins for AVM B 1b and AVM B 1a , respectively. Residual AVMs (sum of AVM B 1a , AVM B 1b and 8,9-Z-AVM B 1a ) in the vegetable were ext- racted with acetonitrile, and the silica solid-phase extraction cartridges were used to purify the extracts. AVMs were derivatized using trifluoroacetic acid and 1-methylimidazole, and the derivatives were determined with a fluorescence detector (excitation at 365 nm and emission at 470 nm). High and consistent recoveries, ranging from 93% to 115%, were obtained for AVM B 1a and 8, 9-Z-AVM B 1a at fortified levels of 20 g/kg and μμ μ 200 g/kg for paprika. The limit of quantitation (LOQ) was 2 g/kg. The residual levels of AVMs in pap μ μ μ μ μ μ μ μ - rika in a field experiment from one day to seven days after the last application decreased from 18.40 to 7.59 g/kg. The half-life (T μμ μ 1/2 ) of AVMs in paprika was 1.47 days.

Degradation of the acaricides abamectin, flufenoxuron and amitraz on Saudi Arabian dates

Degradation of the acaricides abamectin, flufenoxuron and amitraz on date palms, Phoenix dactylefera var. Nabout Seif, grown in Saudi Arabia was studied during the post-harvest interval (PHI) under the local weather and soil conditions. The initial deposit of abamectin residues on dates was 0.09 mg/kg, which declined to 0.03 (66%) and 0.02 mg/kg (88%) after 7 and 14 days of spraying, respectively (PHI = 10 days, MRL = 0.03 mg/kg). The initial deposit of flufenoxuron was 0.68 mg/kg and declined to 0.25 (68%), 0.07 (90%) and 0.03 mg/kg (96%) after 16, 52 and 60 days, respectively (PHI = 50 days, MRL = 0.1 mg/kg). Finally, the initial deposit of amitraz was 0.34 mg/kg which declined to 0.02 mg/kg (95%) and was not detected (100%) after 21 and 30 days, respectively (PHI = 28 days, MRL = 0.01 mg/kg). The acceptable daily intake (ADI) for fruits and vegetables set by FAO/WHO for the three acaricides tested was based on regular and average consumption of fruit, however, in Saudi Arabia, and other neighboring countries, natives consume more date (more than 10 times) than an average person living outside this region. Such high date consumption could lead to a higher risk of exposure to pesticides, especially in children and other vulnerable individuals.

Abamectin compatibility with the leafminer parasitoid Diglyphus isaea

Abstract The most promising non-chemical approach for controlling Liriomyza leafminers in greenhouses is the augmentative/inoculative releases of the parasitoid Diglyphus isaea. However, the insecticide/miticide abamectin is still an important chemical control method against Liriomyza leafminers and the mite complex that attacks numerous greenhouse crops. It is not uncommon for abamectin to be applied where Diglyphus is being used for leafminer control. Consequently, there is a need to develop compatibility data for this material and Diglyphus. The effect of abamectin on D. isaea (adults and larvae) was investigated using laboratory and greenhouse experiments. Direct application and uptake of abamectin had a significant negative effect on the survival of D. isaea adult (both sexes). Abamectin residue on chrysanthemum leaves had a significant negative effect on adult D. isaea female longevity up to 5 days after application. Abamectin was lethal for D. isaea larvae when applied directly to larvae or when contaminated leafminer larvae were consumed by parasitoid larvae. However, the percent emergence of D. isaea was not affected by abamectin treatments when applied to chrysanthemum plants that contained parasitoid larvae. Moreover, the longevity of these emerged adults was not affected by abamectin applications. In light of these data, abamectin compatibility with D. isaea for leafminer control in IPM programs for greenhouses is discussed.

Degradation of Abamectin and Doramectin on Sheep Grazed Pasture

Avermectins are widely used veterinary medicines. They bind strongly to faeces in their non-metabolized form and their half-life in faeces depends on field conditions. There are conflicting data regarding the behaviour of avermectins in the environment. Therefore, we investigated the degradation of abamectin and doramectin on sheep grazed pasture under field conditions in soil, soil-faeces and faeces samples from day 6 to day 70 (abamectin) or to day 50 (doramectin) after sheep treatment. Field conditions were recorded periodically during the experiment. Degradation of abamectin in sheep faeces and in soil-faeces was observed until day 60, with small amounts present in faeces until 70 days post treatment. Because the concentration of abamectin residues in soil was very low on day 6 after treatment, further significant degradation could not be measured. The concentration of doramectin in all analysed matrices decreased rapidly until day 50. It can be concluded that high concentrations of both avermectins were present during the first 20 days after treatment and that field conditions have an important role in degradation of avermectins on grazed pasture of treated animals. Clear identification of the consequences of avermectin exposure and the period of the greatest environmental risk will require further investigations.

Simultaneous Determination of Emamectin, its Metabolites, Milbemectin, Ivermectin and Abamectin in Tomato, Japanese Radish and Tea by LC/MS

We developed a simple and rapid analytical method for determining the residues of emamectin benzoate, milbemectin, abamectin, ivermectin and emamectin metabolites in tomato, Japanese Radish and Japanese tea by liquid chromatography/mass spectrometer (LC/MS) with electrospray ionization (ESI). A sample extracted with acetone was simply cleaned up using only a Sep-Pak C18, and then directly measured by LC/MS (ESI). Several LC/MS measurement conditions were studied that included the mobile phase, solvent for sample solution, range of calibration and standard deviation of the measurement. Detecting target macrocyclic lactone chemicals with methanol as the mobile phase was more sensitive than acetonitrile, especially, milbemectin. The detection limits of these chemicals were 0.1 to 0.5 ng/ml (10 μl injection), and they were similar or more sensitive to the previous fluorescence detection method. For the measurement of these chemicals in tomato, Japanese radish and tea by LC/MS (ESI), ion suppression was always observed. To compensate for such an effect, we used a matrix-matched calibration. This compensation method is effective for obtaining accurate values. The recoveries by the developed method were in an acceptable range for the screening method and 90.1-120.9% except for milbemectin and abamectin from tea leaves that had interfering peaks.

Determination of abamectin and azadirachtin residues in orange samples by liquid chromatography–electrospray tandem mass spectrometry

A rapid and sensitive LC–ESI-MS–MS method has been developed for the determination of azadirachtin and abamectin residues in orange samples. Samples were extracted with acetonitrile, in a high-speed blender. After the addition of sodium acetate, an aliquot of extract was directly injected into the LC–ESI-MS–MS system. The highest sensitivity of the method was achieved under MS–MS conditions using [M+Na] + adducts as precursor ions. Recoveries for both compounds from spiked orange samples at 0.01 and 0.1 mg/kg were above 80%, with good repeatability (<10%). Method detection limits achieved (<0.007 mg/kg) were adequate for the determination of these pesticides in this kind of sample from the regulatory point of view. The importance of the solvent used for extraction, as well as the addition of sodium acetate to the extracts and the selection of adequate chromatographic conditions are discussed.

Comparison of various liquid chromatographic methods for the analysis of avermectin residues in citrus fruits

Various liquid chromatographic (LC) techniques for analyzing avermectin (Abamectin) were compared after extraction of residues from citrus fruit samples by matrix solid-phase dispersion (MSPD). LC with UV and fluorescence detection were used as also was LC coupled to the mass spectrometer by an electrospray interface. The results obtained by the three methods were compared in terms of sensitivity and selectivity. The combination of MSPD extraction and LC with fluorescence detection have made it possible to quantify 0.5 μg kg −1 of Abamectin in 0.5 g of orange sample, with an overall average recovery of 94%. The procedure provides a simple and sensitive method for monitoring Abamectin residues in citrus fruit at the levels required by legislation.

Reproduction and Survival of the Dung BeetleOnthophagus binodis(Coleoptera: Scarabaeidae) Exposed to Abamectin and Doramectin Residues in Cattle Dung

Two groups of 50 heifers were given a subcutaneous injection of either abamectin (Avomec) or doramectin (Dectomax) at a dose rate of 200 μg/kg live weight. A third group of 50 heifers remained untreated. Dung samples were collected on 1, 3, 6, 9, 18, 24, 34, and 42 d after injection, and excreted residues were bioassayed using the dung beetle Onthophagus binodis Thunberg. Fewer newly emerged adults of O. binodis survived exposure to dung from cattle treated 3 and 6 d previously with abamectin or 9 d previously with doramectin than from dung of untreated cattle. Both compounds induced a range of sublethal effects on O.binodis. Abamectin residues excreted in dung up to 42 d after injection had a deleterious impact on ovarian condition, brood mass (egg) production, and larval survival. Doramectin residues only had a deleterious effect on these parameters at 3 and 6 d after injection relative to dung from control cattle. Analysis of the dung collected at each date after injection indicated that moisture content, pH, and percent nitrogen were not different from other physicochemical profiles conducted on cattle dung. Doramectin residues attained maximal concentrations of 101.1 μg/kg 3 d after injection followed by a linear decline with an elimination half-life estimate of 15 d. The bioassay data indicated that doramectin concentrations of <60 μg/kg have minimal impact on the mortality and reproductive potential of O. binodis and that deleterious effects to this species will be evident for only 1–2 wk after administration of the drug to cattle. The potential ecotoxic effects of these compounds are discussed in terms of dung beetle activity and strategies for parasite control of cattle in the Australian environment.

Determination of abamectin in citrus fruits by liquid chromatography–electrospray ionization mass spectrometry

Liquid chromatography coupled to electrospray mass spectrometry (LC–ES-MS) with positive ion detection was used to determine abamectin in oranges. MS conditions were optimized to achieve maximum sensitivity. The main ion for abamectin was [M+Na] + at a fragmentor voltage of 180 V. Abundant structural information can be obtained at different fragmentor voltages. The detection limit for the standard solution was 12 pg injected, and good linearity and reproducibility were observed. Abamectin residues were extracted using matrix solid-phase dispersion. Orange samples were homogenized with C 18 bonded silica placed onto a glass column and eluted with dichloromethane. Recoveries of the abamectin from oranges fortified with approximately 0.01–10 mg/kg ranged from 94 to 99% with an overall average recovery of 96%. The quantification limit is 0.0025 mg/kg, which means detection limit for this analyte could be set at a few hundred picograms per gram of fruit. The presence in the electrosprayed solution of numerous citrus constituents did not interfere significantly with the ionization process of abamectin. The assay procedure provides a simple, rapid, and sensitive method for monitoring residues in oranges. The method was applied to field treatment orange samples.