Cardiotoxicity among Children Accidentally Exposed to Organophosphate Insecticides Coupled with Scorpion Bites in Gaza

Insecticides are toxic chemicals used at homes for controlling insects of public health importance and controlling agricultural pests at home gardens. Their application may result in accidental poisoning. Four accidental insecticide-poisoning children coupled with a scorpion bitten child were brought to the main hospital in southern Gaza for medical treatment. Primary investigation showed severe breath shortness, low heartbeat, and low blood pressure (hypotension). These symptoms are indications of potential cardiotoxicity among children. Electrocardiograms were measured and indicated various heart complications between cases. Complete blood count (CBC) determination showed the highest white blood cells (WBC) in the scorpion-bitted child suggesting the development of immune defense system. Blood electrolyte (Na+, K+, Ca2+) concentrations indicated disturbances due to poisoning. An interesting outcome of the study is the dramatic alteration in blood glucose concentration. Additionally, activity of acetylcholinesterase (AChE) indicated normal activity in poisoning case 1, moderate inhibition in poisoning case 2 and case 3, normal activity in poisoning case 4 and severe inhibition in poisoning case 5. The levels of Aminotransferase (ALT) and Aspartate Aminotransferase (AST) were within the acceptable range whereas the level of Alkaline Phosphatase (ALP) was above the acceptable reference range suggesting potential Hepato-toxicity. Scorpion bitten child did not receive atropine whereas two poisoned cases were successfully cured by atropine injection. Additionally, alternative safe medical management may be used for cardiotoxicity using vitamin C, vitamin E, quercetin, and curcumin. These vitamins may be recommended as alternative medical treatments for cardiotoxicity.

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.

CHEMICAL INCORPORATING INSECTICIDES 1.SYNTHESIS OF NEWPYRETHROIDS WITH ORGANOPHOSPHATE AS POTENTIAL INSECTICIDES

Abstract: Several potential insecticides were synthesized by incorporating chrysanthemic acid and O,O-dialkyl phosphorodithioate through a pyrrolongdine-2,5-dione group. Their structures were determined by elementary analysis, NMR, IR and MS.

Pollution characteristics and risk assessment of organophosphate esters in aquaculture farms and natural water bodies adjacent to the Huanghe River delta

To date,little attention has been paid to the effects of organophosphate esters(OPEs)pollution on aquacultural environment and aquatic product safety.Huanghe(Yellow)River delta area is one of the largest aquaculture centers in China,where ecological security protection is crucial in the national strategy of China.To explore the pollution characteristics,bioaccumulation,and health risks of OPEs in aquaculture farms in the Huanghe River delta and natural water bodies in the adjacent seas,five species of organisms from different farm types nearby the Huanghe River delta,and the corresponding culture water and sediments were sampled in this study.The total concentrations of Σ_(13)OPEs in water,sediments,and organisms were 51.53-272.18 ng/L,52.63-63.17 ng/g dry weight(dw),and 46.82-108.90 ng/g dw,respectively.Among the five types of culture ponds,the water samples from the swimming crab and hairy crab culture ponds exhibited higher OPEs,the concentration of OPEs in the sediments from the few ponds was relatively balanced,and the OPEs in the organism from the holothurian ponds was higher.Tris(1,3-dichloro-2-isopropyl pho sphate)(TDCP)was the main contaminant in water samples and tripropyl phosphate(TPrP)in sediments and organisms.However,trisphenyl phosphate(TPhP)showed the strongest bioaccumulation ability,followed by 2-ethylhexyl diphenyl phosphate(EHDPP)and TPrP.The bioaccumulation capacities of the five species were as follows:prawn>holothurian>hairy crab>swimming crab>carp.These five types of organisms,as main seafood in human consumption,were at low risk of negative impacts of pollution.However,the risk from the mixture of organophosphate flame retardants(OPFRs)still requires more attention due to the increasing consumption and production in the world.

Biochemical indicators and the Peradeniya Organophosphate Poisoning scale in prediction and prognosis of organophosphorus poisoning:An observational prospective study

Objective:To study the value of some biochemical indicators and Peradeniya Organophosphate Poisoning scale in prediction and prognosis of organophosphorus poisoning.Methods:This was a hospital-based prospective,observational study.Various biochemical tests viz.complete blood count,random blood sugar,liver and renal function tests,creatine phosphokinase,and electrolytes were performed.Patients were assessed based on the Peradeniya Organophosphate Poisoning scale.All the patients were followed till the end point like recovery/death.Results:Out of the 100 patients,72%were males and 28%were females.The majority of the patients were farmers and 21 to 30 years of age.Suicidal was the most common manner(92,92%).Based on the Peradeniya Organophosphate Poisoning scale,47%were mild,34%moderate,and 19%severe.Serum creatinine,creatine phosphokinase,serum glutamic-oxaloacetic transaminase,serum glutamic pyruvic transaminase,and alkaline phosphatase levels showed a significant correlation with severity.Conclusions:Some biochemical indicators such as creatine phosphokinase,alkaline phosphatase can be used as prognostic markers of organophosphorus poisoning.The Peradeniya Organophosphate Poisoning scale can be used for assessing severity of the poisoning.

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.

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.

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.

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.

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.

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.

Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues

Organophosphate insecticide residues on vegetable, fruit, tea and even grains are primary cause of food poisoning. Organophosphate compounds can cause irreversible inhibition of the activity of acetylcholinesterase and butyrylcholinesterase（BChE, EC 3.1.1.8）, which are both candidates for rapid detection of organophosphate pesticides. To develop an easy-tohandle method for detecting organophosphate pesticides using BChE, BChE from human was optimized according to the codon usage bias of Pichia pastoris and successfully expressed in P. pastoris GS115. The codon-optimized cDNA shared 37.3% of the codon identity with the native one. However, the amino acid sequence was identical to that of the native human butyrylcholinesterase gene（h BCh E） as published. The ratio of guanine and cytosine in four kinds of bases（（G＋C） ratio） was simultaneously increased from 40 to 47%. The recombinant hBChE expression reached a total protein concentration of 292 mg m L^–1 with an activity of 14.7 U m L^–1, which was purified 3.2×10^3-fold via nickel affinity chromatography with a yield of 68% and a specific activity of 8.1 U mg^–1. Recombinant hBChE was optimally active at pH 7.4 and 50°C and exhibited high activity at a wide pH range（〉60% activity at pH 4.0 to 8.0）. Moreover, it had a good adaptability to high temperature（〉60% activity at both 50 and 60°C up to 60 min） and good stability at 70°C. The enzyme can be activated by Li^＋, Co^＋, Zn^2＋ and ethylene diamine tetraacetic acid（EDTA）, but inhibited by Mg^2＋, Mn^2＋, Fe^2＋, Ag^＋ and Ca^2＋. Na^＋ had little effect on its activity. The values of h BChE of the Michaelis constant（Km） and maximum reaction velocity（Vm） were 89.4 mmol L^–1 and 1 721 mmol min^–1 mg^–1, respectively. The bim olecular rate constants（K_i） of the hBChE to four pesticides were similar with that of electric eel AChE（EeAChE） and higher than that of horse BChE（HoBChE）. All vlues of the half maximal inhibitory concentration of a substance（IC50） for hBChE were lower than those for HoBChE, but most IC50 for hBChE were lower than those for EeAChE except dichlorvos. The applicability of the hBChE was further verified by successful detection of organophosphate insecticide residues in six kinds of vegetable samples. Thus, hBChE heterologously over-expressed by P. pastoris would provide a sufficient material for development of a rapid detection method of organophosphate on spot and produce the organophosphate detection kit.

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.

Evaluation of Efficacy of Insecticides and Long-Lasting Insecticidal Nets for Control of Culex quinquefasciatus Say Populations from Northern Nigeria

Information on Culex mosquitoes (vectors of filarial worm and viral encephalitis) from northern Nigeria is scanty, hindering evidence-based control. Here, two Culex populations (Kano and Kaduna) were characterized. Culex quinquefasciatus and Culex pipiens were found breeding in sympatry, with some hybrid individuals identified. Larval bioassays revealed high temephos resistance (LC50s = 1.34 mg/mL and 3.01 mg/mL for Kano and Kaduna, respectively). Larvae were more sensitive to α-cypermethrin (LC50s = 0.026 mg/mL and 0.067 mg/mL for Kano and Kaduna). WHO adult tube bioassays revealed high pyrethroid and DDT resistance, with mortalities of 44.01% ± 6.79%, 35.83% ± 12.58%, 29.69% ± 9.97% and 52.47% ± 4.34% for permethrin, deltamethrin, α-cypermethrin and DDT, respectively. Highest resistance was observed with bendiocarb (mortality = 13.58% ± 3.98%). High resistance was obtained with fenitrothion and malathion (mortalities = 21% ± 4.76% and 56.47% ± 8.67%, respectively), while a full susceptibility was observed with pirimiphos-methyl. Pre-exposure to piperonylbutoxide (PBO) significantly recovered α-cypermethrin susceptibility (mortality = 82% ± 5.16%, χ2 = 50.99, p < 0.0001), compared with the conventional bioassay (mortality = 32 ± 7.30). Mortalities of <20% were obtained in cone bioassays with Yorkool, DuraNet and PermaNet3.0 (side panels) nets, suggesting a loss of efficacy of conventional long-lasting insecticidal nets. However, mortalities of 99% and 86% were obtained in Kano and Kaduna populations using the roof of PermaNet3.0 (containing PBO and deltamethrin). Despite the high frequency of the 1014F VGSC knockdown resistance mutation allele (0.90), no correlation was observed between the 1014F kdr genotype and resistance phenotype. Sequencing of fragments of the acetylcholinesterase-1 gene detected no G119S mutation, in malathion-alive and malathion-dead females. These suggest a preeminent role of metabolic resistance in these Culex populations.

Evaluation of Insecticides Targeting Control of Helicoverpa armigera(Hubner)(Lepidoptera:Noctuidae)

Insecticides from different chemical groups were tested by laboratory bioassay to verify the percentage mortality of Helicoverpa armigera (Hubner 1808) (Lepidoptera: Noctuidae). The experiment was conducted in the Crop Science laboratory—Prof. CinobelinaElvas Campus—UFPI, Bom Jesus, PI, from January to June, 2013. The populations utilized came from the University’s own insect breeding laboratories. Third instar larvae of H. armigera were used to conduct the bioassay. The experimental design was fully randomized, with 13 treatments and four replications. Five larvae were used per replication, with 12 insecticides from 9 different chemical groups and a control. Each treatment consisted of three doses. The methods of application used were topical contact and ingestion in artificial diet. According to the results the percentage mortality of H. armigera larvae varied among the treatments. The results demonstrated that chlorpyrifos and spinosad were effective against third instar H. armigera larvae both on contact and by ingestion. Flubendiamide, acephate, methomyl, Bacillus thuringiensis, dimethoate, chlorantraniliprole and fipronil had good responses to control of H. armigera.

Studies on the Purification and Characterization of Soybean Esterase,and Its Sensitivity to Organophosphate and Carbamate Pesticides

Soybean esterase, a cholinesterase-like enzyme, was purified by differential centrifugation firstly, then, ammonium sulfate precipitation, dialysis, and finally, DEAE-cellulose-32 ion-exchange chromatography after extracting it from soybean seeds with phosphate buffer （0.3 mol L^-1, pH 7.0）. The extract recovery rate of the purified enzyme was 8.18% and purification fold was 91.58. The soybean esterase appeared as two bands on the denaturing SDS-PAGE with molecular weights of 24 and 37.2 kDa, respectively, which proved that it is a dimer protein consisting of two subunits. The result of nondenaturing PAGE revealed that the soybean esterase is a single band with cholinesterase-like activity using α- naphthyl acetate as the substrate and fast blue B salt as coloring agent. The esterase showed very high sensitivity to 18 kinds of organophosphate pesticides and 6 kinds of carbamate pesticides with the lowest detective limits of 0.03125- 0.0625 and 0.03125-0.25 mg kg^-1, respectively, and can meet the demands of MRL specified by the most countries.

Susceptibility of Different Populations of Nilaparvata lugens from Major Rice Growing Areas of Karnataka, India to Different Groups of Insecticides

Susceptibility to insecticides was investigated by collecting field populations of brown planthopper from different locations of southern Karnataka, India （Gangavati, Kathalagere, Kollegala, Soraba and Mandya）. All the field populations differed in their susceptibility to insecticides. In general, Soraba and Mandya populations were more susceptible to insecticides compared to Gangavati and Kathalagere populations. The resistance ratios varied greatly among the populations viz., chlorpyriphos （1.13- to 16.82-fold）, imidacloprid （0.53- to 13.50-fold）, acephate （1.34- to 5.32-fold）, fipronil （1.13- to 4.06-fold）, thiamethoxam （1.01- to 2.19-fold）, clothianidin （1.92- to 4.86-fold）, dinotefuran （0.82- to 2.22- fold）, buprofezin （1.06- to 5.43-fold） and carbofuran （0.41- to 2.17-fold）. The populations from Gangavati Kathalagere and Kollegala exhibited higher resistance to some of the old insecticides and low resistance to new molecules.

Insensitive Acetylcholine Receptor Conferring Resistance of Plutella xylostella to Nereistoxin Insecticides

The combinative rate measurement of （3-[I125] iodotyrosyl） α-bungarotoxin was applied in the analysis of the relation between nerve acetylcholine receptor and three types of insecticide resistance in diamondback moth, Plutella xylostella （L.）. In the dimehypo-resistant strain and in the cartap-resistant strain, the nerve acetylcholine receptor showed the remarkable insensitivity to dimehypo and cartap, of which the binding rate to ligand was approximately 66 and 60%, respectively, of the susceptible strain. The sensitivity to deltamethrin in the deltamethrin-resistant strain did not show visible change. These results indicated that the decline in the sensitivity of nerve acetylcholine receptor to insecticide might be a potential mechanism to nereistoxin insecticides resistance in the diamondback moth.