Inputs of organochlorine insecticides to Xiamen coastal waters

This paper quantifies organochlorine insecticides （OC1） inputs in the Jiulong River and shows the large use in the agricultural activities and analyses specifically the status of soil, fruit and vegetable contamination by these persistent pollutants in some locations of Xiamen region. From this purpose, soil samples collected from Jiulong agricultural catchment have been analyzed for 18 selected OCI using gas chromatography electron capture detection and to identify the factors that may control the distribution and persistence of organochlorines in the area. The main insecticides found in soil samples were Aldrin, Dieldrin, Endosulfan I1, Endrin aldehyde, Endosulfan sulphate and Methoxychlor. The total organochlorines detected in soil samples ranged from 3.14 to 10.35 ng/g soil. The highest values of OC1 were significantly detected in the orange trees＇ leaves, which range from 1203 to 2681 ng/g soil showing recent uses of these agrochemicals. Their distribution in vegetable samples were also monitored and indicating that the concentration ranged from 3.236 to 7.188 ng/g. The contamination of Jiulong River estuary by organochlorine pesticides has been then widely justified by soil runoffs from these agricultural areas. The results therefore, provide important information on the current contamination status and point to the need for urgent actions to stop the use of persistent agrochemicals. The necessity of implementing systematic monitoring of insecticide contamination is emphasized.

Laboratory evaluation of toxicity of selected insecticides against egg and larval stages of cotton pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae)

Background The cryptic nature of pink bollworm Pectinophora gossypiella(Saunders)larvae enables its reduced vul-nerability to insecticidal control.Further,the development of resistance against Bacillus thuringiensis(Bt)toxins posed a serious threat to transgenic cotton cultivation.This necessitated determining the critical timing of spray applications on the control effectiveness.This study assessed the influence of egg age(freshly laid vs.three-day-old)and the loca-tion of larvae(directly exposed to the insecticide residues on the boll rind vs.burrowed inside the bolls)on insecticide control efficacy.Results The results revealed a significant decrease in the ovicidal activity of tested insecticides with an increase in the age of eggs from one day old to three days old(paired t-test,P<0.05).The larvae directly exposed to the insec-ticide residues on the boll rind were more susceptible(>80%mortality)than the larvae exposed after they had bur-rowed inside the bolls(<49%mortality).The inhibitory effects of tested insecticides on developmental biology were more pronounced in the experiment on pre-larval release insecticide treatment compared with insecticide treatment given post-larval release and entry inside the bolls.Conclusion Egg age influences the insecticide susceptibility,as does the larval location,directly exposed vs bur-rowed inside the bolls.Older eggs and the larvae that had burrowed inside the green bolls of cotton were relatively less susceptible to the insecticide treatments.The toxic effects of insecticides on egg and larval stages were primar-ily ephemeral.These findings are significant for devising a comprehensive strategy for pink bollworm management on a sustainable basis.

Increase in Organochlorine Contaminant Levels in Major Water Sources of the United States in Response to the Coronavirus Pandemic

Organochlorine contaminants, such as triclosan (TCS), are present in major water sources across the United States. These antimicrobial compounds are widely used as multipurpose ingredients in everyday consumer products. They can be ingested or absorbed through the skin and are found in human blood, breast milk, and urine samples. Studies have shown that the increased use of antimicrobial agents leads to their presence and persistence in the ecosystem, particularly in soil and watersheds. Many studies have highlighted emerging concerns associated with the overuse of TCS, including dermal irritations, a higher incidence of antibacterial-related allergies, microbial resistance, disruptions in the endocrine system, altered thyroid hormone activity, metabolism, and tumor metastasis and growth. Organochlorine contaminant exposures play a role in inflammatory responsiveness, and any unwarranted innate response could lead to adverse outcomes. The capacity of TCS and other organochlorine contaminants to induce inflammation, resulting in persistent and chronic inflammation, is linked to various pathologies, such as cardiovascular disease and several types of cancers. Chronic inflammation presents a severe consequence of exposure to these antimicrobial agents, as any changes could result in the loss of immune competence. Organochlorine contaminant levels were established by the United States Environmental Protection Agency (EPA) in 2019-2020 and have consistently increased in response to the novel coronavirus (nCoV) (COVID-19) pandemic. Our previous research examined the overuse of products containing triclosan (TCS), which led to an increase in total trihalomethane (TTHM) levels affecting the quality of our water supply. We also investigated the impact of the FDA ban that now requires pre-market approval. To comprehend the consequences of excessive antimicrobial use on water quality, we conducted an analysis of the levels of total trichloromethane (chloroform), a byproduct of free chlorine added to TCS, in primary water sources in metropolitan areas across the United States in 2019-2020. We repeated this analysis after the peak of the COVID-19 pandemic in 2021-2022 to examine its correlation with organochlorine exposure. Our study found that the COVID-19 pandemic, along with the increased use of antimicrobial products, has significantly raised the levels of total trihalomethanes compared to those reported in water quality reports from 2019-2020, in contrast to the reports from 2021-2022.

Risk of control failure to insecticides malathion,profenophos+cypermethrin mixture,and fipronil in boll weevil(Coleoptera:Curculionidae)populations from Bahia,Brazil

Background To control the boll weevil Anthonomus grandis grandis(Coleoptera:Curculionidae),a key pest of cotton in the Americas,insecticides have been intensively used to manage their populations,increasing selection pressure for resistant populations.Thus,this study aimed to detect insecticide resistance and assess insecticide control failure likelihood of boll weevil populations exposed to malathion,profenophos+cypermethrin,and fipronil insecticides.Results Twelve populations of the boll weevil were collected from commercial cotton fileds of the state of Bahia,northeastern Brazil.These populations were exposed to malathion,profenophos+cypermethrin mixture,and fipronil,at their respective maximum label dose for field applications.Three replicates of 10 adult beetles were exposed to the insecticides and mortality was recorded after 24 h treatment.The control failure likelihood was determined after 48 h.Highest median lethal times(LT_(50))were observed for malathion and the profenophos+cypermethrin mixture.Resistance to at least one insecticide was detected in 11 populations;three populations were resistant to malathion and profenophos+cypermethrin;seven were resistant to all insecticides tested.The resistance levels were low(<10-fold)for the three insecticides.Among 12 populations tested,58%of them exhibited significant risk of control failure for the insecticides malathion and profenophos+cypermethrin.The insecticide fipronil was efficient for the control of the boll weevil in 83%of the populations.Conclusions The results confirm the significant risk of insecticide control failure in the boll weevil populations to the main compounds used in the region.Thus,proper insecticide resistance management plans are necessary for the boll weevil in the region,particularly for malathion and profenophos+cypermethrin insecticides.

Research on the Control Effects of Several Insecticides on Wheat Aphids

[Objective] The aim was to determine control effects of the 6 insecticides and recommended the optimal doses. [Method] In 2014, the control effects of sophocarpidine, pymetrozine, beta-cypermethrin, acetamiprid, imidacloprid, and chlor- pyrifos on wheat aphids were tested, and every pesticide was designed with three doses in Shou County, Anhui Province, to explore the significance of differences on control effects. [Result] The results showed that the control effects of the 6 insecti- cides were satisfied, and the insecticides were safe on wheat. [Conclusion] During initial diseasing stage of aphid, it is recommended to use sophocarpidine soluble concentrate （1.5%）, pymetrozine water dispersible granule （50%）, imidacloprid wet- table powder （25%）, and acetamiprid wettable powder （5%）, and chlorpyrifos missi- ble oil （40%）, cypermethrin missible oil （4.5%） and imidacloprid wettable powder （25%） can be applied in peak-diseasing stage.

Contamination by Organochlorine Pesticides in the Estuaries of Southeast China

Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiulong River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC ECD. The results showed that the contamination levels were similar in these three estuaries. The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocyclohexane(HCH) compounds, β HCH was found to be the most important isomer. The analysis of 1,1,1 trichloro 2,2 bis chlorophenyl ethane(DDT) and its metabolites showed that 1,1 dichloro 2[ o chlorophenyl] 2[ p chlorophenyl] ethylene(DDE) was dominant in the group.

Study on Detection of Organochlorine Pesticide Residue in Ginseng

To investigate the residue situation of pesticides in ginseng, total 17 samples of ginseng-growing soil, ginseng roots and ginseng seeds were collected from 5 regions of Fusong County, and the contents of organochlorine pesticide residues in the samples were detected by using ultrasonic-assisted extraction and gas chromatography with acetone-ligroin as the solvent, thereby providing suitable recommendations and scientific basis for the selection of ginseng-growing soil.

Irritability of malaria vector,Anopheles sacharovi to different insecticides in a malaria-prone area

Objective:To determine the susceptibility and irritability level of malaria vector Anopheles sacharovi(An.sachrovi) to different insecticides in a malaria-prone area.Methods:Susceptibility and irritability levels of field collected strain of An.sacharovi to WHO standard papers of DDT 4%,dieldrin 0.4%,malathion 5%,fenitrothion 1%,permethrin 0.75%,and deltamethrin 0.05% were determined in East Azerbaijan of Iran during reemerging of malaria as described by WHO.Results:Results showed that at the diagnostic dose of insecticides this species exhibited resistance to DDT,tolerant to dieldrin and but somehow susceptible to fenitrothion,malathion, permethrin and deltamethrin.The results of irritability of this species to DDT,lambdacyhalothrin. permethrin cyfluthrin and deltamethrin revealed that DDT had had the most and deltamethrin the least irritancy effect.The average number of take offs/fly/minules for DDT was 0.8±0.2.The order of irritability for permethrin,lambdacyhalothrin,cyfluthrin and deltamethrin were 0.7±0.2,0.5±0.2, 0.5±0.3,and 0.2±0.1,respectively.Conclusions:Results of this study reveals the responsiveness of the main malaria vector to different insecticides.This phenomenon is depending on several factors such as type and background of insecticide used previously,insecticide properties,and physiology of the species.Careful monitoring of insecticide resistance and irritability level of species could provide a clue for appropriate selection of insecticide for malaria control.

Determination of Resistance to Seven Insecticides in Plutella xylostella L. in Fields of Northern Hunan

The resistance of field populations of Plutella xylostella, from the three vegetable producing areas （Nianyuxu Town of Yueyang City, Canggang Town of Changde City and Shatou Town of Yiyang City） in northern Hunan, to seven insecticides was determined using leaf dipping method in door. The results showed that Plutella xylostella showed an extremely high-level resistance to beta-cypermethrin （resistance ratio, RR=257.13）, a high-level resistance to abamectin （RR=135.15） and indoxacarb （RR=103.08） and a moderate-level resistance to chlorfenapyr and emamectin benzoate. But Plutella xylostella is relatively sensitive to chlorantraniliprole and Bacillus thuringiensis （Bt）. Therefore, the prevention of Plutella xylostella in northern Hunan should focus on the alternative use of chlorfenapyr, emamectin benzoate, chlorantraniliprole and Bacillus thuringiensis and avoid the use of beta-cypermethrin so as to delay the generation and development of resistance to insecticides in Plutella xylostella.

Pharmacophore model for neonicotinoid insecticides

An effective prediction pharmacophore model （RMS = 0.634, Correl = 0.893, Weight = 1.463, Config = 11.940） was successfully obtained by 3D-QSAR based on a series of nAChR （nicotinic acetylcholine receptors） agonists, which consists of a hydrogen- bonding acceptor, a hydrogen-bond donor, a hydrophobic aliphatic and a hydrophobic aromatic centre. This pharmacophore model may provide theoretical basis for designation and development of higher active insecticides.

Detection of Persistent Organochlorine Pollutants in Eggs of Antarctic Seabirds Based on Gas Chromatography and Their Ecological Environment Significance

By using internal standard method based on gas chromatography-electron capture detector （GC-ECD）, the contents of persistent or- ganochlorine pollutants polychorinated biphenyls （PCBs） and organochlorine pesticides （OCPs） in eggs of seabirds （ Catharacta Ionnbergi, Cathar- acta maccormicki, Pygoscelis papua and Macronectes giganteus） breeding on King George Island, Antarctica were detected, and their ecological environment significance was discussed. The results showed that the recovery of various compounds ranged from 68.6% to 90.8% ; relative stand- ard deviation （RSD） was 3.6%, and the lowest detection limits of PCBs and OCPs were 0.8 - 16 and 2 - 12 pg respectively, which could meet the demands for the residue analysis of trace persistent organochlorine pollutants in the eggs of Antarctic seabirds. The contents of PCBs, DDTs, HCB and HCHs in the eggs of Antarctic seabirds were 0.5 -515.5, 2.0 -304.4,0.5 -70.5, and 0.5 -2.0 ng/g respectively. In addition, the accumula- tion of PCBs and OCPs in the skuas was enhanced gradually through the food chain. The maximums of persistent organochlorine pollutants ap- peared in the eggs of C. Ionnbergi, followed by the eggs of C. maccomicki. The detection of OCPs and PCBs in the eggs of Antarctic seabirds was not interfered by other compounds containing chlorine, showing that the extraction, purification and detection method was suitable for the analysis of OCPs and PCBs in the eggs of Antarctic seabirds and has high sensitivity and reliability.

The Relationship Between Resistance to Controlled Atmosphere and Insecticides of Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae)

The cross resistance of four resistant strains of Liposcelis bostrychophila Badonnel, an important stored-product insect pest, was investigated. These four strains included the HCO2-R (hypercarbia-resistant strain), HCLO-R (hypoxia and hypercarbia resistant strain), DDVP-R (DDVP-resistant strain) and PH3-R (PH3-resistant strain). The results indicated that there were cross-resistances between CA and insecticides, and the quantities of the cross-resistance were different. The cross-resistance factor (RF) of HCO2-R to hypoxia and hypercarbia was 3.2458, whilst, that of HCLO-R to hypercarbia was 1.8280. The RF of DDVP-R to PH3 was 3.9614, whilst, that of PH3-R to DDVP was 2.7852. The RF values of DDVP- R and PH3-R to hypercarbia were 1.3550 and 1.1816, respectively. However, the RF of HCO2- R to DDVP was 2.1372. There also was a low cross-resistance between DDVP-R and HCO2-R. The RF of HCO2-R to PH3 was 3.3698. This suggested that the insects resistant to high CO2 concentration atmosphere would develop significant resistance to PH3. However, the insects resistant to PH3 remain sensitive to hypercarbia atmosphere. Both DDVP-R and PH3- R developed resistance to high CO2 treatment. There was a low cross-resistance between DDVP-R and HCLO-R. The insects resistant to hypoxia and hypercarbia were very sensitive to DDVP. There also was cross-resistance between HCLO-R and PH3-R, but the resistance of PH3-R to hypoxia and hypercarbia was lower than that of HCLO-R to PH3. The difference of the overlapping and separate values indicated that there were differences in the intercross-resistance of four resistant strains.

Monitoring of Organochlorine Pesticide Residues──The GEMS/Food Program in China

This paper covers the monitoring activities of organochlorine (OCS) pesticide residues in the GEMS/Food program, which China took part in for the first time in 1992. The levels of HCH and DDT were determined in 355 samples of eight main varieties of food , taken from five provinces and cities. The results show that the positive rate of HCH is 69%, of which 99. 44 % is in accord with the National Standards of Food Hygiene of China. As to DDT, the two rates are 42 % and 100 % respectively. The daily intakes of HCH and DDT are 0. 22 mg/ kg.bw and 0. 54 mg/kg. bw respectively, which are far below their corresponding ADIs.Compared with those in 1970s, the OCS residues have decreased significantly. Therefore the monitored varieties of food are safe to people's health

Indoor Efficacy Experiment of 13 Insecticides against Tea Geometrid (Ectropis Oblique Hypulina Wehrli)

[Objective]The paper was to study indoor efficacy of 13 insecticides against tea geometrid（Ectropis Oblique Hypulina Wehrli）.[Method]Thirteen insecticides were sprayed onto indoor hydroponic young tea shoots with infesting third instar larvae of tea geometrid reared in the laboratory to simulate the actual condition in the tea garden,and their efficacy was studied.[Result]The control efficacies of 60 g/L spinetoram SC 3 000 times dilution,3% emamectin benzoate ME 15 000 times dilution,240 g/L methoxyfenozide SC 5 000 times dilution and 240 g/L metaflumizone SC 1 500 times dilution were all greater than 91% after spraying for 7d.The control efficacy of 20%tebufenozide SC 1 000 times dilution remained 86.48%.Although the control efficacy of 20%flubendiamide WDG 6 000 times dilution was slightly lower than the above five treatments,the dry weight of faeces was the second least,and its protection effect on leaves was only second to spinetoram.Therefore,60g/L spinetoram SC,3% emamectin benzoate ME,240 g/L methoxyfenozide SC,240 g/L metaflumizone SC,20% tebufenozide SC and 20% flubendiamide WDG were ideal insecticides that could be used rotationally to control tea geometrid in tea garden.The control efficacy of 10% bifenthrin EC 3 000 times dilution was only 23%,so the insecticide was not suitable for control against the pest.[Conclusion]The paper proposed an alternate insecticide for field control against tea geometrid.

Efficacy Test of Different Insecticides on Pseudaulacaspis pentagona Infecting Pitaya

[Objective] The aim was to select insecticides effective in contrlling Pseudaulacaspis pentagona Infecting Pitaya. [Method] Efficacy effects of 11 insecticides in 22 concentrations were performed on Pseudaulacaspis pentagona Infecting Pitaya. [Result] When the insecticides were sprayed after 14 d, the treatment group with 22.4% spirotetramat SC at two concentrations proved the best, with control effects at 95.24% and 92.05%, followed by Nurelle at two concentrations, with control effects at 90.86% and 89.19%, and the control effects of chlorpyrifos （x2 000） was the poorest at only 67.08%. Therefore, it is feasible to make use of 22.4% spirotetramat SC, chlorpyrifos EC and Nurelle EC alternatively in controlling Pseudaulacaspis pentagona in case of pesticide resistance. [Conclusion] The research provided references for scientific use of insecticides in controlling Pseudaulacaspis pentagona Infecting Pitaya.

Advances in Analytical Techniques for Organochlorine Pesticide Detection in Tea Samples

The pretreatment and analytical techniques for organochiorine residues, including ultrasonic extraction, accelerated solvent extraction pesticide microwave extraction, solid phase extraction, and solid-phase micro-extraction and the analytical techniques of gas chromatography and gas chromatography-mass spectrometry）in tea samples in recent years were reviewed. The prospect of organochlorine pesti- cide residue analysis was proposed in this paper.

Toxicity and Field Efficacy of Six Insecticides on Alfalfa Thrips (Thysanoptera: Thripidae)

Alfalfa thrips,especially the bird s-foot trefoil thrips(Odontothrips loti Haliday),is a major pest in the alfalfa field.Toxicity and field efficacy of 6 insecticides were determined by leaf disk in tube method and foliar spray,respectively.The results showed LC 50 values of chlorfenapyr 24%SC,lambda-cyhalothrin 5%EW,sulfoxaflor 22%SC,dinotefuran 20%SG,spinetoram 60 g/L SC and tolfenpyrad 30%SC to Odontothrips loti were 0.11,0.62,2.92,4.24,10.47 and 13.42 mg/L,respectively.The control effects of tolfenpyrad 30%SC,spinetoram 60 g/L SC,sulfoxaflor 22%SC,lambda-cyhalothrin 5%EW and dinotefuran 20%SG against alfalfa thrips were more than 80%after 1 d treatment,showing good readily availability.The control of spinetoram 60 g/L SC and dinotefuran 20% SG was 74.63% and 75.65% after 7 d treatment,showing a long persistence effect respectively.Therefore,spinetoram 60 g/L SC and dinotefuran 20% SG can be used as the first option to control alfalfa thrips.

Determination of trace amounts of chlorinated insecticides and fungicides in ginseng using capillary gas chromatography and ^(63)Ni electron capture detector

A method for the simultaneous determination of a series of chlorinated insecticides and fungicides as residues in ginseng is presented in this article. Pulverized samples are subjected to Soxhlet extraction with acetone-petroleum ether and the extract is partitioned between petroleum ether and aqueous sodium sulfate solution (2:98). The combined petroleum ether phase is cleaned up by sulfuric acid and analyzed by capillary gas chromatography using 63Ni electron capture detector. Recoveries from the different concentrations for 11 kinds of chlorinated insecticides and fungicides are between 92.40 and 103.7% with coefficients of variations ranged 1.22 and 9.53% without samples, and between 89.00% and 104.10% with coefficients of variations between 1.16% and 9.16% with samples. The detection limits are 0.2- 7.0 ng/kg.

The insecticide resistance in two planthoppers from three areas to three insecticides

Migrating insects brown planthopper(BPH),Nilaparvata lugens St(?)l andwhite-backed planthopper(WBPH),Sogatella furcifera Horvath are both mostharmful insects on rice in China.Chemical control is thought to be the best wayto manage them,but it may cause insecticide resistance.Methamidophos,buprofezin,and imidacloprid were the three insecticides often used.In 2000and 2001,resistance of the field populations collected from three areas,i.e.Dongtai,Jiangsu Province,Anqing,Anhui Province,and Guilin,GuangxiAutonomous Region,to the three insecticides was monitored.The toxicities ofthe three insecticides were determined with the female adult(3-5 d after e-mergence)and by the topical application method with the hand microapplicator.

Efficacy of Reduced-Risk Insecticides to Control Flower Thrips in Early-Season Blueberries and Their Effect on <i>Orius insidiosus</i>, a Natural Enemy of Flower Thrips

Flower thrips are one of the key pests in production of southern highbush blueberries (Vaccinium corymbosum L. × V. darrowi Camp). They feed on the reproductive parts of the flower and reduce yield. Very few insecticides are available to manage thrips population. Therefore, it is necessary to evaluate pre-existing and experimental insecticides for their efficacy against thrips. There is also a high demand for reduced-risk insecticides that are less toxic to beneficial insects and the environment. In this study, a number of conventional and reduced-risk insecticides were evaluated against flower thrips on farms in Florida and Georgia and in the laboratory. The best performing insecticides were also evaluated in the laboratory for their effects on Orius insidiosus Say, which is a common thrips’ predator in Florida. Assail 70WP (Acetamiprid) and SpinTor 2SC (Spinosad) were the most promising insecticides in reducing thrips numbers in the field as well as in laboratory experiments. SpinTor 2SC killed all of the thrips in laboratory arenas within 4 hours of application and showed low toxicity toward O. insidiosus. All of the compounds tested performed as well as the conventional pesticide malathion.