Kinds Of Insecticides Research Articles

The mechanistic pathway induced by fenpropathrin toxicity: Oxidative stress, signaling pathway, and mitochondrial damage.

Fenpropathrin (FNP) is a kind of insecticide and acaricide known as pyrethroid. It is very effective, has a wide range of activities, and works quickly. Internationally, it is commonly considered the most powerful pyrethroid insecticide. Nevertheless, an increasing amount of data indicates a substantial link between Fenpropathrin and adverse effects on nontarget species, including liver toxicity, kidney toxicity, nerve damage, and reproductive toxicity. Oxidative stress plays a vital role in the toxicity of fenpropathrin, in addition to its mechanical mechanism. This study offers a thorough examination of the harmful effects of Fenpropathrin on oxidative and mitochondrial processes, as well as the signaling pathways involved in these effects. The significant impact of oxidative stress emphasizes the toxicity of Fenpropathrin.

Effects of CO2 elevation on life-history traits of two insecticide-resistant strains of planthopper Nilaparvata lugens on rice.

We made separate experiments to examine life-history traits and activities of protective enzymes as affected by carbon dioxide (CO2) elevation to 780 μL/L as compared to 390 μL/L in imidacloprid- or buprofezin-resistant strains of the brown planthopper (BPH) Nilaparvata lugens. We found an interaction effect between resistance and the CO2 level on the nymphal survival and duration in both resistant strains. Nymphal durations in both resistant strains were much shorter in the resistant than susceptible BPH at 780 μL/L but similar between them or slightly shorter in the resistant than susceptible BPH at 390 μL/L. Nymphal survival was lower for imidacloprid-resistant than its susceptible BPH at 390 μL/L but higher at 780 μL/L; it stayed unaffected by the CO2 elevation in buprofezin-resistant BPH. We did not observe an interaction effect between resistance and the CO2 level on major reproductive parameters in both resistant strains. But the 2 strains were not consistent across CO2 levels in all parameters. Our measurements of protective enzyme activities of superoxide dismutase, catalase, and peroxidase showed an interaction between resistance and the CO2 level. Overall, these enzymes became similar in activity between resistant and susceptible BPH at 780 μL/L compared to 390 μL/L and the change was more distinct in the imidacloprid- than buprofezin-resistant BPH strains. Our findings suggest that CO2 elevation can affect life-history traits of insecticide-resistant BPH, while the effect may vary depending on the kind of insecticides it is resistant to.

Rapid Detection of A282S Mutation in the RDL1 Gene of Rice Stem Borer via the Mutation-Specific LAMP Technique

Rice stem borer Chilo suppressalis (Walker) is one of the most serious pests on rice and is distributed worldwide. With the long-term and continuous usage of insecticides, C. suppressalis has developed high levels of resistance to various kinds of insecticides, including phenylpyrazole insecticides. As is well known, the resistance of C. suppressalis to phenylpyrazole insecticides is determined by the A282S mutation of the GABA receptor RDL subunit. In order to efficiently detect the resistance of C. suppressalis, a rapid and sensitive loop-mediated isothermal amplification (LAMP) technique was established and optimized in this study. The optimal concentration of components was Bst DNA polymerase (0.24 U/μL), dNTP (0.8 mM), Mg2+ (4 mM), betaine (0.6 M), forward inner primer and backward inner primer (1.6 μM), F3 and B3 (0.4 μM), and hydroxyl naphthol blue (150 mM), respectively, and the optimal reaction condition was 63 °C for 60 min, which could reduce the cost and time of detection. In addition, the accuracy of the optimized LAMP reaction system and parameters was verified in the field strains of C. suppressalis from different regions, including Jiangsu, Jiangxi, and Hu’nan provinces. The mutation (A2’S) was successfully detected in the field strains. As far as we know, this is the first report of the LAMP technique applied in the resistance monitoring of C. suppressalis to phenylpyrazole insecticides. According to our results, the optimized LAMP reaction system is feasible and easy to operate and to efficiently detect resistance-related mutation in a short time, as directly judged by the naked eye. Our results provide a new tool for detection of resistance of C. suppressalis, which is a very useful tool for comprehensive management of C. suppressalis.

A General Signal Pathway to Regulate Multiple Detoxification Genes Drives the Evolution of Helicoverpa armigera Adaptation to Xenobiotics.

The study of insect adaptation to the defensive metabolites of host plants and various kinds of insecticides in order to acquire resistance is a hot topic in the pest-control field, but the mechanism is still unclear. In our study, we found that a general signal pathway exists in H. armigera which can regulate multiple P450s, GSTs and UGTs genes to help insects decrease their susceptibility to xenobiotics. Knockdown of HaNrf2 and HaAhR expression could significantly increase the toxicity of xenobiotics to H. armigera, and simultaneously decrease the gene expression of P450s, GSTs and UGTs which are related to the xenobiotic metabolism and synthesis of insect hormone pathways. Then, we used EMSA and dual luciferase assay to verify that a crosstalk exists between AhR and Nrf2 to regulate multiple P450s, GSTs and UGTs genes to mediate H. armigera susceptibility to plant allelochemicals and insecticides. The detoxification genes' expression network which can be regulated by Nrf2 and AhR is still unknown, and there were also no reports about the crosstalk between AhR and Nrf2 that exist in insects and can regulate multiple detoxification genes' expression. Our results provide a new general signaling pathway to reveal the adaptive mechanism of insects to xenobiotics and provides further insight into designing effective pest-management strategies to avoid the overuse of insecticides.

Study on the control effect of 7 kinds of insecticides to ficus gallforming thripid

The toxicity and control efect of 7 kinds of insectcides to Ficus gall-forming thripid are evaluated in this paper. The results showed the toxicity of Decis is the highest. The toxicites of Imidacloprid and Cypermethrin are higher than that of the other 4 kinds of insectcides,the toxicity of Regent is the lowest. Decis, Admire and Chlorpyrifos provided efectve rapid control efects, which are 99. 3%, 98. 9% and 94. 2% respectvely at 3 days afer the treatment. Admire and Chlorpyrifos provided efectve residual control efects, which are 92.8% and 86.5% respectvely at 21 day s afer the treatment.

Can Toxicities Induced by Insecticide Methomyl be Remediated Via Soil Bacteria Ochrobactrum thiophenivorans and Sphingomonas melonis?

The research study was about revealing the biochemical response of Gammarus pulex related to insecticide methomyl before and after bioremediation by two soil bacteria species, Ochrobactrum thiophenivorans and Sphingomonas melonis. Catalase (CAT), glutathione S-transferase.(GST), cytochrome. P4501A1 (CYP1A1) activities in G. Pulex related to methomyl solution were investigated in 24h and 96h. ELISA method was used for test studies. CAT enzyme was decreased in Gammarus pulex that was exposed to methomyl after all exposure period (P < 0.05). CAT activities were returned to control results after bioremediation assays. GST enzyme activity was decreased depending on methomyl exposure during 24h but increased during 4days (P < 0.05). After 8days of bioremediation period, GST activity increased again during 24h while decreased during 4days (P < 0.05). CYP1A1 activity increased in Gammarus pulex that was exposed to methomyl after all exposure period (P > 0.05). After bioremediation, statistically significant changes were not revealed in CYP1A1 activities (P > 0.05). According to the results of our study, CYP1A1, CAT, and GST activities in G. pulex sanctioned the capability of Ochrobactrum thiophenivorans and Sphingomonas melonis in methomyl bioremediation. Isolated and enriched Ochrobactrum thiophenivorans and Sphingomonas melonis that were added to 2.5ppb concentrations of methomyl for 8 days. Each day, chemical oxygen demand (COD) and biochemical oxygen demand (BOD5), pH and dissolved oxygen parameters were monitored. At the final phase of the bioremediation step, it was determined that these bacteria have efficient methomyl bioremediation properties in a mixed corsortia at a rate of 86%. These results show that these bacteria can be used for bioremediate the receiving environments that are polluted by these kinds of insecticides.

RNA interference of tyrosine hydroxylase caused rapid mortality by impairing cuticle formation in Nilaparvata lugens (Hemiptera: Delphacidae).

The application of RNA interference (RNAi) technique in controlling agricultural insect pests has been receiving much attention since the discovery of RNAi. The brown planthopper (BPH) Nilaparvata lugens, a notorious pest of rice, has evolved a high level of resistance to many kinds of insecticides. Tyrosine hydroxylase (Th) is an indispensable survival gene in holometabolous insects, playing key roles in cuticle tanning and immunity. In this study, we investigated whether Th could be used as a potential target in controlling N. lugens. Here, we demonstrated that NlTh had a periodical expression pattern during molting with the highest level observed in epidermis. Dysfunction of NlTH by dsNlTh microinjection or 3-IT feeding similarly caused rapid death of N. lugens. Compared with dsGFP control BPHs, dsNlTh injected BPHs (i) had cuticle pigmentation and sclerotizaton defects; (ii) had less endocuticle lamella in tergum integument; (iii) showed higher mortality during the molting process as a result of defective cuticle shedding; (iv) showed feeding disorders indicated by a low number of probe wound dots on rice; (v) had more vulnerable cuticle. This study demonstrated that TH orthologues play a conservative and crucial role for exocuticle tanning in both holometabolous and hemimetabolous insects, and NlTh could be targeted for RNAi-mediated BPH control. The rapid lethal phenotype of NlTH dysfunction BPHs partly induced by cuticle formation defects. © 2020 Society of Chemical Industry.

Toxicity and effects of four insecticides on Na+, K+-ATPase of western flower thrips, Frankliniella occidentalis.

Western flower thrips (WFT), Frankliniella occidentalis, has become an important pest of vegetables worldwide, due to its economic damage to crop production. In order to control WFT, chemical insecticides are widely used. However, WFT has developed a high resistance against many kinds of insecticides. Na+, K+-ATPase, playing an important role in the ionic transmission across the membrane, is commonly considered to be the target of several xenobiotic compounds. However, whether the Na+, K+-ATPase can be used as one of the target sites for controlling WFT is still unknown. In this study, resistance levels of WFT to four insecticides (chlorpyrifos, beta cypermethrin, abamectin, and thiamethoxam) were measured. It was found that all four insecticides exhibited significant inhibitory effects on WFT, especially on nymphs. The activity of Na+, K+-ATPase was estimated after the treatment of four insecticides. Additionally, mRNA expression levels of three Na+, K+-ATPase α-subunit isoforms (X1, X2 and X3) were detected using RT-qPCR. The transcription profile of three Na+, K+-ATPase α-subunit isoforms were diverse after treatment by these four insecticides, which indicated that these isoforms might play different roles in the tolerance to insecticides. The results suggested that Na+, K+-ATPase can obviously be inhibited by these four classes of insecticide, and may serve as the new target for controlling WFT.

Thermodynamic Models for Determination of Solid–Liquid Equilibrium of the Buprofezin in Pure and Binary Organic Solvents

Buprofezin is a kind of insecticide and an important chemical intermediate product. Data on solid–liquid equilibrium of buprofezin in different solvents is essential for the area of industrial applications. In this work, the solubility of buprofezin in methanol, ethanol, isopropanol, n-butanol, acetonitrile, n-hexane, ethyl acetate, N,N-dimethylformamide, and two binary solvent mixtures (methanol + ethyl acetate and acetonitrile + ethyl acetate) was measured at the temperature range of 278.15–328.15 K at atmospheric pressure by the gravimetric method. The experimental values showed that elevated temperatures increased the solubility of buprofezin in all selected solvents. The modified Apelblat model, the Buchowski–Ksiazaczak λh model, combined nearly ideal binary solvent/Redlich–Kister (CNIBS/R-K) model, Jouyban–Acree model, and an ideal model were used to describe and predict the diversification trend of solubility.

Electrochemical Biosensor for Acetamiprid Based on Aptamer As Captured Probe and Horseradish Peroxidase for Signal Amplification

Nowadays, people pay more attention to the environmental protection and food safety problems caused by pesticide residues. In this paper, a biosensor for sensitive detection of acetamiprid, a kind of insecticide, was fabricated based on aptamer as a captured probe of acetamiprid and horseradish peroxidase (HRP) as a biocatalyst for signal amplification. The schematic diagram of fabrication of the biosensor was shown in Fig. 1. Fig. 1 The preparation of biosensor and the detection of acetamiprid Labeled aptamer of acetamiprid and a complementary DNA strand (cDNA) of the aptamer were synthesized by Shanghai Sangon Biological Engineering Technological Co. Ltd. (China). The base sequences are as-follows:[1] aptamer: 5′-NH2-(CH2)6-TGT AAT TTG TCT GCA GCG GTT CTT GAT CGC TGA CAC CAT ATT ATG AAG A-3′; cDNA: 5′- (SH) - (CH2)6 - T CTT CAT AAT ATG GTG TCA GCG ATC AAG AAC CGC TGC AGA CAA ATT ACA -3′. A 10 mL graphene oxide (GNO) suspension of 1.0 mg/mL was uniformly coated on the surface of a glassy carbon electrode (GCE) by drop-casting and allowed it to dry naturally in the air. The modified electrode (GNO/GCE) was immersed in 0.1 mol/L PBS solution containing of 0.4 mM xanthurenic acid (Xa) and was performed cyclic voltammetry scan from 0.65 V to -1.70 V (vs.SCE) for 10 cycles. GNO as the starting material was electrochemical reduction to ERGO at cathodic potential and the electropolymerization of xanthurenic acid (PXa) was achieved at anodic potential in a simply one-step process by cyclic voltammetry (CV), simultaneously. Because of the π–π* interaction between the conjugated GNO layers and aromatic rings of Xa, GNO can serve as a strong adsorbing platform for Xa monomer and promote the electropolymerization of Xa effectively. [2] After the PXa-ERGO composite film was synthesized, the PXa-ERGO/GCE electrode was immersed in 0.1 M phosphate buffer solution (PBS) of pH 7.0 containing 5.0 mM ethyl-3-(dimethylaminopropyl) carbodiimide (EDC) and 8.0 mM N-hydroxysuccinimide (NHS) to convert the terminal carboxylic group to active NHS ester. Double-helix DNA (dsDNA) was prepared by the hybridization between aptamer and cDNA. Then the dsDNA solution was coated on the surface of the PXa-ERGO/GCE electrode and incubated for 2 hours. The rich carboxylic groups of PXa-ERGO film were applied to immobilize the dsDNA with amino groups at 5’ end of cDNA by covalent bonding. The biosensor was denoted as dsDNA/PXa-ERGO/GCE. Gold nanoparticles (AuNPs) and HRP–AuNPs conjugates were prepared. Transmission electron microscope (TEM) images and ultraviolet-visible absorption spectra were used to characterize the AuNPs. AuNPs-HRP conjugates were modified onto the dsDNA/PXa-ERGO/GCE though Au–thiol interactions. Hydroquinone (HQ) and H2O2 in solution were catalyzed by HRP to generate an anodic voltammetric peak. The aptamer biosensor was successfully applied to determine acetamiprid by differential pulse voltammetry (DPV). The analysis was based on the change in the anodic peak current (i p) before and after sample solutions were applied to the surface of the working electrode at room temperature. When the background current stabilized, the anodic peak current response was recorded as i p0. In the presence of acetamiprid, aptamers bind with acetamiprid to produce a complex on the electrode surface. The HRP–AuNP–cDNA conjugates therefore fall off from the electrode surface. The anodic peak current decreased and was recorded as i p. The change in current was given by Δi p = i p0 - i p. A 25 mL aliquot of 0.1 M PBS (pH 7.4) was placed in a voltammetric cell and the required volumes of 3.0 mM HQ and 1.5 mM H2O2 solution were added. The DPV potential scan was performed from -0.4 V to 0.6 V (vs.SCE) at pulse amplitude of 20 mV, pulse frequency of 25 Hz and increment potential of 4 mV. Under the optimal conditions, the Δi p value highly and linearly increased with the increase in the logarithm of the acetamiprid concentration (c) over a range from 0.010 to 20 μg/L, with a detection limit of 0.005 μg/L. This aptamer sensor was applied in the determination of acetamiprid in river water with high specificity, sensitivity and selectivity.

Susceptibility of Brown Planthopper (Nilaparvata lugens Stal.) from Cipunagara and Banyuwangi Population to Neem Oil Formulation

Brown Planthopper is one of the pests that cause problems in rice production. This study was conducted to know the tendency of using a kind of insecticide and to examined the susceptibility of brown planthopper from field population (Cipunagara, West Java) compared to standard population (Banyuwangi, East Java) to formulation insecticide of neem oil 50 EC. Observations wereconducted on Cipunagara farmers to find out the kind of insecticide used and the number of insecticide applications in one season. the susceptibility test to neem oil 50 EC formulation was conducted by root dipping method. Brown planthopper was feed on treated plant for two days and then the next day the Brown Planthopper was fed on rice plant without treatment until the eighth day. Test insects used are brown planthopper instar 4 th . Observations of insect mortality test for ten days with an interval of every 24-hour observation. Susceptibility values for neem oil insecticide formulations were determined based on the resistance ratio (RR) by comparing the LC 50 value of the field population and standard population. Result of the observations showed that the farmers in the Padamulya village, Cipunagara district generally using synthetic insecticides to control of this pest. The active ingredient of most mentioned was imidacloprid with a lot of different applications. The result of examination of insecticide formulation of neem oil 50 EC using the root dipping method showed that a slow death trend and the highest mortality at eight days after application. The LC 50 value of neem oil 50 EC insecticide against brown planthopper in the field population (Cipunagara) was 0.36% and RR 0.98. The result indicated that brown planthopper origin from Cipunagara was still susceptible to neem oil 50 EC insecticide formulation. Keyword: Neem oil formulation, Susceptilbility, Resistance ratio, Brown Planthopper

Susceptibility of Brown Planthopper (Nilaparvata lugens Stal.) from Cipunagara and Banyuwangi Population to Neem Oil Formulation

Brown Planthopper is one of the pests that cause problems in rice production. This study was conducted to know the tendency of using a kind of insecticide and to examined the susceptibility of brown planthopper from field population (Cipunagara, West Java) compared to standard population (Banyuwangi, East Java) to formulation insecticide of neem oil 50 EC. Observations wereconducted on Cipunagara farmers to find out the kind of insecticide used and the number of insecticide applications in one season. the susceptibility test to neem oil 50 EC formulation was conducted by root dipping method. Brown planthopper was feed on treated plant for two days and then the next day the Brown Planthopper was fed on rice plant without treatment until the eighth day. Test insects used are brown planthopper instar 4 th . Observations of insect mortality test for ten days with an interval of every 24-hour observation. Susceptibility values for neem oil insecticide formulations were determined based on the resistance ratio (RR) by comparing the LC 50 value of the field population and standard population. Result of the observations showed that the farmers in the Padamulya village, Cipunagara district generally using synthetic insecticides to control of this pest. The active ingredient of most mentioned was imidacloprid with a lot of different applications. The result of examination of insecticide formulation of neem oil 50 EC using the root dipping method showed that a slow death trend and the highest mortality at eight days after application. The LC 50 value of neem oil 50 EC insecticide against brown planthopper in the field population (Cipunagara) was 0.36% and RR 0.98. The result indicated that brown planthopper origin from Cipunagara was still susceptible to neem oil 50 EC insecticide formulation. Keyword: Neem oil formulation, Susceptilbility, Resistance ratio, Brown Planthopper

Overexpression of CYP6ER1 associated with clothianidin resistance in Nilaparvata lugens (Stål)

The brown planthopper, Nilaparvata lugens (Stål), is one of the most economically important rice pests in Asia and has become resistant to various kinds of insecticides, including neonicotinoid insecticides. In this study, an N. lugens clothianidin-resistant (CLR) strain and a susceptible (CLS) strain were established, and the potential resistance mechanisms of N. lugens to clothianidin were elucidated. The cross-resistance studies showed that the clothianidin-resistant strain exhibited cross-resistance to most neonicotinoid insecticides, especially nitenpyram (99.19-fold) and dinotefuran (77.68-fold), while there was no cross-resistance to chlorpyrifos (1.79-fold). The synergism assays and the activities of the detoxification enzymes were performed, and we found that a cytochrome P450 conferred the clothianidin resistance. Two P450 genes (CYP6ER1 and CYP6AY1) were found to be significantly overexpressed in the CLR strain compared with the CLS strain based on qRT-PCR. In addition, the knockdown of CYP6ER1 by RNA interference dramatically increased the toxicity of clothianidin against N. lugens. These data demonstrated that the overexpression of CYP6ER1 could contribute to clothianidin resistance in N. lugens. Our findings will help to improve the design of effective resistance management strategies to control brown planthoppers.

Synergistic effect and field control efficacy of the binary mixture of permethrin and chlorpyrifos to brown planthopper (Nilaparvata lugens)

Abstract The brown Planthopper (BPH), Nilaparvata lugens is a major pest of rice production in tropical Asia. The appearance of insecticide resistance challenges the control of BPH in field. The development of new insecticide is expensive and time-consuming. Thus, the precise and proper use of existing compounds becomes an important issue in resistance management of this pest. In this study, five commercial insecticides of BPH (permethrin, chlorpyrifos, imidacloprid, clothianidin and thiamethoxam) were tested to explore the toxicity of the binary mixture between different kinds of insecticides. In all combinations of mixture, the mixtures of permethrin and chlorpyrifos displays synergistic effect at three different mixture ratios (1:1, 1:10 and 10:1). The strongest synergism observed in permethrin/ chlorpyrifos mixtures at 1:1 ratio (Combination index, CI = 0.39). Addition of enzyme inhibitor followed by detoxification enzyme activity assays suggested that the mechanism of synergistic effect of permethrin/chlorpyrifos mixture may result from inhibition of the cytochrome P450 monooxygenase and esterase activity. This inference can be supported through two lines of evidence. One is decrease of toxicity when permethrin/chlorpyrifos mixture in a 1:1 ratio plus triphenyl phosphate (TPP) or piperonyl butoxide (PBO), but increase of toxicity when permethrin/chlorpyrifos mixture in a 10:1 ratio plus TPP or PBO. Another is exposure of the 3rd instar nymphs to permethrin/chlorpyrifos mixture after 72 h also significantly decreased both cytochrome P450 monooxygenases and esterase activity. Further field trail showed the mixture of 50 ppm permethrin +50 ppm chlorpyrifos increased the field control efficiency significantly rather than permethrin alone or chlorpyrifos alone. Our study indicated that the mixture of permethrin and chlorpyrifos in a 1:1 ratio might be an effective method for the control of BPH in paddy field.

Oxidative stress induced by camptothecin and hydroxyl-camptothecin in IOZCAS-Spex-II cells of Spodoptera exigua Hübner

Camptothecin (CPT) and its derivatives show potential insecticidal activities against various insect species due to target at DNA-Topoisomerase I complex and induce apoptosis death of insect cells. Oxidative stress resulted from excessive production of reactive oxygen species (ROS) has been proved to be an important component of the mechanism of pesticide toxicity. The aim of the present study was to investigate whether CPTs promote the increasing of intracellular oxidative stress by enhancing accumulation of intracellular ROS in IOZCAS-Spex-II cells derived from Spodoptera exigua Hübner. Results demonstrated that there was a significant increase in the level of intracellular ROS accompanied by markedly increased DNA damage, lipid peroxidation and protein carbonylation after exposing to CPT and hydroxyl-camptothecin (HCPT) in IOZCAS-Spex-II cells. These results documented ROS generation induced by CPT and HCPT played an essential role in toxicity and mode of action of CPTs against insects. This research will throw new light on the critical roles of oxidative stress in CPTs- induced toxicity against insects, as well as on the exploration of using CPTs as a kind of insecticide with unique mode of action in the future.

Effects of abamectin and deltamethrin to the foragers honeybee workers of Apis mellifera jemenatica (Hymenoptera: Apidae) under laboratory conditions.

This study aimed at evaluating the toxicity of some insecticides (abamectin and deltamethrin) on the lethal time (LT50) and midgut of foragers honeybee workers of Apis mellifera jemenatica were studied under laboratory conditions. The bees were provided with water, food, natural protein and sugar solution with insecticide (concentration: 2.50 ppm deltamethrin and 0.1 ppm abamectin). The control group was not treated with any kind of insecticides. The mortality was assessed at 1, 2, 4, 6, 12, 24, 48, and 72 hour (h) after insecticides treatment and period to calculate the value of lethal time (LT50). But the samples the histology study of midgut collected after 24 h were conducted by Scanning Electron Microscope. The results showed the effects of insecticides on the current results show that abamectin has an adverse effect on honeybees, there is a clear impact on the lethal time (LT50) was the abamectin faster in the death of honeybee workers compared to deltamethrin. Where have reached to abamectin (LT50 = 21.026) h, deltamethrin (LT50 = 72.011) h. However, abamectin also effects on cytotoxic midgut cells that may cause digestive disorders in the midgut, epithelial tissue is formed during morphological alterations when digestive cells die. The extends into the internal cavity, and at the top, there is epithelial cell striated border that has many holes and curves, abamectin seems to have crushed the layers of muscle. Through the current results can say abamectin most toxicity on honeybees colony health and vitality, especially foragers honeybee workers.

Pesticides Toxicity in fish with particular reference to Insecticides

Aquatic Toxicology is the study of the effects of environmental pollutants on aquatic organisms, such as pesticides especially the insecticides, on the health of fish or other aquatic organisms. Pesticides are substances used to control pests, including insects, aquatic weeds, plant diseases, and Aquatic snails that carry the cause of schistosomiasis. Pesticides have been found to be highly toxic not only to fish but also to the other organisms, which constitute the food chain. Pesticides in general, are used very extensively in agriculture, forestry, public health and in veterinary practices. Pesticides are categorized according to their target use. The three major pesticides are herbicides (weed control), insecticides (insect control), and fungicides (Mycotic control), but the more acute toxicity are insecticides. Since fishes are important sources of proteins and lipids for humans and domestic animals, so health of fishes is very important for human beings. Insecticides are the chemicals used to control insects by killing or preventing them from engaging in unwanted behaviors or destructive. The contamination of surface waters by insecticides is known to have ill effects on the growth, survival and reproduction of aquatic animals. Different concentrations of insecticides are present in many types of waste water and numerous studies have found them to be toxic to aquatic organisms, especially fish species. Application of insecticides used for control a wide variety of insectivorous and herbaceous pests which would otherwise diminish the quantity and quality of food production. Unfortunately, in spite of its advantages, chemistry has great disadvantages as well as insecticides are threatening the long-term survival of major ecosystems by disruption of ecological relationships between organisms and loss of biodiversity. The major Chemical groups of insecticides that are usually applied Organophosphate, Carbamates, Organochlorine, Pyrethroids, and Necotenoides. The insecticidal residues which contaminate the water are mainly due to the intensive agriculture combined with surface runoff and surface drainage, usually within a few weeks after application. Insecticides lead to decrease rate of growth, reproductive disorders. Also, cause spinal deformities and histopathological changes in gills, liver, hematopoietic tissue such as spleen, head of the kidney and renal tubules, endocrine tissues as well as brain, neurological, behavioral disorder and genetic defect are other biological indicators of exposure to insecticides. Fishes are particularly sensitive to the environmental contamination of water. Hence, these pollutants such as insecticides may significantly damage certain physiology and biochemical processes that different kinds of insecticides can cause serious impairment to physiological and health status of fishes. Aquaculture is one of the fastest growing food producing sectors, supplying approximately 40% of the world's fish food. Besides such benefit to the society, the industry does have its problems. Potentially harmful substances are often release into the aquatic environment. When is the launch of large quantities of pollutants there might be an immediate impact as measured by mortality the sudden large-scale aquaculture, for example, fish kills caused by pollution of water ways with agricultural pesticides. Lower levels of discharge may result in accumulation of pollutants in aquatic organisms. The final results, which may occur after a long period has passed pollutants through the environment, and include immune suppression, low metabolism, and damage to the gills and epithelia. This review presents further information concerning effects (Acute, sub chronic and chronic) of the different concentrations of pesticides (including insecticides) on various aspects of fish's biology and physiology. Also, depicts behavior, genetic and immune system of fish. The information given in this review facilitates the evaluation of potential toxic hazard resulting from exposure to different levels of these compounds. Data could be acquired useful in environmental risk assessment of freshwater organisms and marine. The histopathological changes in fish tissues used as a biological indicator for pollution with pesticides with special reference to insecticides. Finally, Protection of wildlife and water quality is possible when rationalize the use of pesticides. Also, when Pesticides must choosing judiciously and are used in combination with other pest management tools, and applied safely, the surface water pollution and contamination of our aquatic life could be avoided.

Population dynamics and control techniques of aphids on honeysuckle

The objective of this study is to define the population dynamics of Semiaphis heraclei in the main-producing district of Lonicera japonica in Shandong, and screen for highly efficient, safety control technique. Through fixed field investigation, we tested the toxicity of eight kinds of insecticides by using dipping methods, and carried out the field experiment. The results showed that the aphids' emergence peak appeared in May. The aphids on the Sijihua variety of L. japonica was more susceptible and the peak was also seven days earlier than Damao variety of L. japonica. The aphid populations on Sijihua were 1 fold than those on the Daomao in happened peak. Comparing the eight kinds of insecticides, the LC50 of lambda-cyhaothrin, abamectin, imidacloprid and pyrethrin to wingless aphids were 1.494, 1.690, 2.840, 2.861 mg x L(-1), respectively, whose toxicity were higher, the toxicity of matrine, pymetrozine and azadirachtin were also high. The field efficacy trials indicated that during the period of aphids occurred, 25% imidacloprid wettable powder, 1.8% abamectin missible oil, 2.5% lambda-cyhaothrin missible oil, 25% pymetrozine wettable powder, 5% pyrethrin missible oil, 1% matrine water aqua were sprayed at concentrations of 20,000, 2,000, 2,500, 5,000, 500 and 50 times, respectively,the control effect achieved 91.69%, 98.90%, 96.18%, 95.06%, 99.24%, 90.10%, respectively, after 5 days. During the growing period of L. japonica in spring, application of thiamethoxam, thiacloprid, pymetrozine and imidacloprid, all of the control effect against aphids achieved above 98.88% after 50 days. The result indicated that May was the S. heraclei Takahashi's emergence peak in Pingyi, Shandong. The efficient safety and environmentally friendly insecticides by spraying and systemic insecticide of pymetrozine and imidacloprid by root application were all efficient controlled aphids. These insecticides were long for controlling S. heraclei Takahashi and worthy of being widely applied.

딸기에 등록된 살충제의 꿀벌에 대한 급성 및 엽상잔류독성

Abstract This study was performed to evaluate the spray toxicity and leaf residual toxicity of 52 kinds ofinsecticides registered for strawberry against adult honeybee Apis mellifera. According to the IOBC standard,the acute toxicity by spraying showed below 30% was classified as non-toxic. Among tested insecticides, 32insecticides (flonicamid, lufenuron, novaluron, three kinds of acetamiprid, thiacloprid, milbemectin, acequinocyl,TBI-1, two kinds of chlorfenapyr, chlorfluazuron, cyenopyrafen, cyfumetofen, etoxazole, fenpyroximate,flubendiamide, flufenoxuron, hexythiazox, metaflumizone, two kinds of methoxyfenozide, DBB-2032, pyridalyl,spiromesifen, tebufenpyrad, teflubenzuron, acetamiprid + methoxyfenozide, acrinathrin + spiromesifen, bifenazate+ spiromesifen, cyenopyrafen + flufenoxuron) did not show any toxic effect, it is thought to be safe. And theothers (20 insecticides) showed higher toxicity to honeybee. Insecticides which showed acute toxicity higherthan 90% was selected and tested the residual toxicity. All insecticides except emamectin benzoate EC, andindoxacarb SC showed 100% mortality at one day after treatment (DAT). However, the toxicities ofemamectin benzoate, indoxacarb SC, and abamectin did not show until 3, 7, 14 DAT, respectively. Nineinsecticides such as indoxacarb WP, thiamethoxam WG, abamectin + chlorantraniliprole SC, acetamiprid +etofenprox WP, acetamiprid + indoxacarb WP, bifenthrin + clothianidin SC, bifenthrin + imidacloprid WP,bifenazate + pyridaben SC, chlorfenapyr + clothianidin SC showed over 90% residual toxicity until 31 Day.In pouring treatment, thiamethoxam WG showed 76.9% mortality at 28 DAT and 50.0% mortality at 31 DAT.After 35 days, thiamethoxam WG showed no effect to honeybee. Bifenthrin + clothianidin SC andtefluthrin + thiamethoxam GR showed 57.1 and 80.0% mortality at 24 DAT, respectively. In sprayingtreatment, thiamethoxam WG and bifenthrin+clothianidin SC showed very high residual toxicity with 100%mortality in thirty-five DAT. After spraying treatment with thiamethoxam WG, bifenthrin+clothianidin SC,bifenthrin + imidacloprid WP, thiamethoxam WG showed 100% residual toxicity until 21 DAT and there wasno activity after 28 DAT. Bifenthrin+clothianidin SC and bifenthrin+imidacloprid WP showed very highresidual toxicity until 49 DAT.Key words Honeybee, Insecticide, Residual toxicity, Strawberry*Corresponding authorTel: +82-43-220-5841, Fax: +82-43-220-5839E-mail: hyenmo01@korea.krORIGINAL ARTICLES / TOXICOLOGY

Baseline Toxicity of Metaflumizone and Lack of Cross Resistance Between Indoxacarb and Metaflumizone in Diamondback Moth (Lepidoptera: Plutellidae)

Diamondback moth, Plutella xylostella (L.) is a serious insect pest of vegetables worldwide, and has evolved resistance to various kinds of insecticides. Studies were conducted to determine the baseline toxicity of metaflumizone and the possibility of cross-resistance between metaflumizone and indoxacarb, two sodium channel blocking insecticides (SCBIs), in field populations of P. xylostella from China. The variation in susceptibility to metaflumizone among 29 field populations of P. xylostella collected from 14 geographical locations in China was less than five-fold, with 50% lethal concentrations (LC50(s)) varying from 1.34 to 6.55 mg/liter. Limited variations in LC50(s) (less than five-fold, ranging from 1.76 to 8.16 mg/liter) were also observed in the four laboratory-selected strains with high levels of resistance to abamectin, spinosad, fipronil, or Bt toxin Cry1Ac. The toxicity of metaflumizone and indoxacarb was compared among 23 out of the 29 field populations. When compared with the susceptible Roth strain, the JN-09B population showed the highest level of resistance to indoxacarb (110-fold), but two-fold tolerance to metaflumizone. The other 22 populations (with 5- to 58-fold of resistance to indoxacarb) had 1- to three-fold tolerance to metaflumizone. Metaflumizone could provide an effective alternative insecticide for diamondback moth management. Although the field populations of P. xylostella tested with various levels of resistance to indoxacarb did not have cross-resistance to metaflumizone, metaflumizone should be rotated with other chemicals of different modes of action instead of indoxacarb.