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 acciden...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<sup>+</sup>, K<sup>+</sup>, Ca<span style="font-size:10px;"><sup>2+</sup></span>) 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.展开更多
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(B...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.展开更多
Background & Objectives: Epidemics of arboviruses such as Dengue, Chikungunya and Zika have been recorded in recent years indicating that Aedes aegypti and Aedes albopictus are both important and very active vecto...Background & Objectives: Epidemics of arboviruses such as Dengue, Chikungunya and Zika have been recorded in recent years indicating that Aedes aegypti and Aedes albopictus are both important and very active vectors in Africa. For vector control, insecticides are on the front line, unfortunately, reported resistance jeopardizes the effectiveness of this strategy. The objective of this review was to determine the geographical distribution and insecticide resistance mechanisms of Ae. aegypti and Ae. Albopictus in Africa. Methods: A systematic review of the literature in scientific databases (PubMed, Google Scholar, ScienceDirect, Hinari) allowed us to identify relevant articles on the geographical distribution of Aedes aegypti, Aedes albopictus and arboviral diseases. On the other hand, studies related to insecticides used in vector control against Aedes, associated resistances and their molecular and metabolic mechanisms. Results: A total of 94 studies met the inclusion criteria for this search. Aedes aegypti is reported in most of Africa, and Aedes albopictus in part. There is a re-emergence and outbreak of Arbovirus epidemics in West and Central Africa. The insecticides used were organochlorines, carbamates, organophosphates and pyrethroids. In Aedes, target site insensitivity and metabolic resistance would be the 2 main mechanisms of resistance to these insecticides. Interpretation & Conclusion: Resistance has been recorded in all four major classes of insecticides recommended by WHO for vector control and eradication. New vector control methods such as the use of plant extracts with larvicidal and adulticidal activities, advanced modern biotechnology techniques, and nanobiotechnology need to be developed.展开更多
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 ...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.展开更多
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 c...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.展开更多
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,observ...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.展开更多
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 ...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.展开更多
[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, imida...[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.展开更多
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, t...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.展开更多
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 f...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.展开更多
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） agonis...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.展开更多
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),...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.展开更多
[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 in...[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.展开更多
[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 pe...[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.展开更多
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 fo...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.展开更多
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 aceto...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.展开更多
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...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.展开更多
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 an...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.展开更多
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 inse...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.展开更多
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. Cu...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 (LC<sub>50</sub>s = 1.34 mg/mL and 3.01 mg/mL for Kano and Kaduna, respectively). Larvae were more sensitive to α-cypermethrin (LC<sub>50</sub>s = 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%, χ<sup>2</sup> = 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.展开更多
文摘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<sup>+</sup>, K<sup>+</sup>, Ca<span style="font-size:10px;"><sup>2+</sup></span>) 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.
文摘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.
文摘Background & Objectives: Epidemics of arboviruses such as Dengue, Chikungunya and Zika have been recorded in recent years indicating that Aedes aegypti and Aedes albopictus are both important and very active vectors in Africa. For vector control, insecticides are on the front line, unfortunately, reported resistance jeopardizes the effectiveness of this strategy. The objective of this review was to determine the geographical distribution and insecticide resistance mechanisms of Ae. aegypti and Ae. Albopictus in Africa. Methods: A systematic review of the literature in scientific databases (PubMed, Google Scholar, ScienceDirect, Hinari) allowed us to identify relevant articles on the geographical distribution of Aedes aegypti, Aedes albopictus and arboviral diseases. On the other hand, studies related to insecticides used in vector control against Aedes, associated resistances and their molecular and metabolic mechanisms. Results: A total of 94 studies met the inclusion criteria for this search. Aedes aegypti is reported in most of Africa, and Aedes albopictus in part. There is a re-emergence and outbreak of Arbovirus epidemics in West and Central Africa. The insecticides used were organochlorines, carbamates, organophosphates and pyrethroids. In Aedes, target site insensitivity and metabolic resistance would be the 2 main mechanisms of resistance to these insecticides. Interpretation & Conclusion: Resistance has been recorded in all four major classes of insecticides recommended by WHO for vector control and eradication. New vector control methods such as the use of plant extracts with larvicidal and adulticidal activities, advanced modern biotechnology techniques, and nanobiotechnology need to be developed.
文摘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.
基金Supported by the Fundamental Research Funds of Shandong University(No.2020GN106)the Project of State Key Laboratory of Environmental Chemistry and Ecotoxicology+3 种基金Research Center for Eco-Environmental SciencesChinese Academy of Sciences(No.KF2020-16)the Ministry of Education Chunhui Plan Project(No.191650)the Young Scholars Project of Xihua University in 2019。
文摘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.
文摘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.
基金supported by Foundation for Research Support of the State of Bahia(FAPESB)the CAPES Foundation(Brazilian Ministry of Education+1 种基金Finance Code 001)for financial supportBahia Association of Cotton Producers。
文摘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.
基金Supported by Pesticide Innovation and Highly Efficient Implementation Technology of Special Foundation for Anhui Talents Development(13C1109)~~
文摘[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.
文摘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.
基金supported by Tehran University of Medical Sciences
文摘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.
文摘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.
基金funded in part by the Nationa1 Natura1 Science Foundation(38800017)of ChinaFok Ying-Tung Education Foundation(71022).
文摘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.
文摘[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.
文摘[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.
基金Shandong Provincial Modern Agricultural Industry Technology System Forage Innovation Team(SDAIT-23-01).
文摘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.
文摘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.
文摘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.
基金financially supported by the Rural Work Committee of Beijing City for the First Batch of Agricultural Science and Technology Project of Beijing University of Agriculture, China (2013010102)the Beijing Innovation Team Building Project of Leafy Vegetables of Modern Agricultural Industry System, China (2063213003)the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions, China (CIT&TCD 20150315)
文摘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.
文摘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.
文摘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 (LC<sub>50</sub>s = 1.34 mg/mL and 3.01 mg/mL for Kano and Kaduna, respectively). Larvae were more sensitive to α-cypermethrin (LC<sub>50</sub>s = 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%, χ<sup>2</sup> = 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.
