bifenthrin and imidacloprid

The concentration of pesticide residues in 105 green tea samples grown in Hangzhou area were investigated. Of the 14 pesticides analysed using gas chromatography-tandem mass spectrometry and the 27 pesticides analysed using liquid chromatography-tandem mass spectrometry, only 18 were detected in the tea samples. The most frequently detected pesticide residues were imidacloprid (35.2%), acetamiprid (26.7%), carbendazim (21.0%), bifenthrin (21.0%), and cyhalothrin (19.1%). Carbofuran was the only pesticide which exceeded in one sample the maximum residue limit. The concentrations of the analytes in tea samples ranged from below the limit of detection (LOD) to 2.64 mg/kg. Their mean concentrations were all below the LOD, except for imidacloprid, acetamiprid, carbendazim, bifenthrin and cyhalothrin. Based on a preliminary long-term exposure assessment, the hazard quotient values of the detected pesticides varied in the range 0.47 × 10

Topics: Food Contamination; Gas Chromatography-Mass Spectrometry; Humans; Pesticide Residues; Pesticides; Risk Assessment; Tea

Harmonia axyridis (Coleoptera: Coccinellidae) is a beneficial predatory arthropod in the agricultural ecosystem. For the success and development of integrated pest management strategies, it is essential to assess the toxicity risks of commonly used pesticides to nontarget arthropods.. The glass tube residue method was used to determine the risk of nine pesticides to H. axyridis after second-instar exposure. To assess the potential risk of the selected pesticides, the pre-adult LR. The four neonicotinoid insecticides (imidacloprid, dinotefuran, thiamethoxam, and acetamiprid), pyrethroid bifenthrin, and organophosphorus dimethoate showed a high risk to H. axyridis. Emamectin benzoate, tebuconazole, and myclobutanil showed a low risk to H. axyridis under both exposure scenarios. The results provide critical scientific evidence to guide future regulation of pesticide management practices and protection of nontarget arthropods like H. axyridis. © 2022 Society of Chemical Industry.

Topics: Animals; Coleoptera; Dimethoate; Ecosystem; Pesticides; Risk Assessment; Thiamethoxam

Topics: Acaricides; Animals; Guanidines; Mites; Neonicotinoids; Nitriles; Nitro Compounds; Pesticides; Pyrethrins; Spiders; Tetranychidae; Thiazoles

Sulfoxaflor is the first commercially available sulfoximine insecticide, which exhibits highly efficacy against many sap-feeding insect pests and has been applied as an alternative insecticide against cotton aphid in China. This study was conducted to investigate the risk of resistance development, the cross-resistance pattern and the potential resistance mechanisms of sulfoxaflor in Aphis gossypii. A colony (SulR strain) of A. gossypii with 245-fold resistance, originated from Xinjiang field population, was established by continuous selection using sulfoxaflor. The SulR strain has developed cross-resistance to imidacloprid (80.8-fold), acetamiprid (19.3-fold), thiamethoxam (10.0-fold), and flupyradifurone (107.5-fold), while no cross-resistance was detected to malathion, omethoate, bifenthrin, methomyl, and carbosulfan. Piperonyl butoxide and S, S, S-tributyl phosphorotrithioate could significantly increase the toxicity of sulfoxaflor to the SulR strain by 5.99- and 4.18-fold, respectively, whereas no synergistic effect with diethyl maleate was observed. The activities of P450s and carboxylesterase were significantly higher in the SulR strain than that in the SS strain. Further gene expression determination demonstrated that nine P450 genes were significantly increased in SulR strain and suppression the expression of CYP6CY13 and CYP6CY19 by RNAi significantly increased the susceptibility of SulR adult aphids to sulfoxaflor. These results demonstrated that the enhancing detoxification by cytochrome P450 monooxygenase may be involved in A.gossypii resistance to sulfoxaflor.

Topics: 4-Butyrolactone; Animals; Aphids; Cytochrome P-450 Enzyme System; Insecticide Resistance; Insecticides; Neonicotinoids; Nitro Compounds; Pyrethrins; Pyridines; Sulfur Compounds

Neonicotinoids, pyrethroids and ketoenols are currently used for the control of Trialeurodes vaporariorum (Hemiptera: Aleyrodidae). In this study, insecticide resistance status and mechanisms were investigated using classical bioassays and molecular techniques.. Dose-response bioassays were performed on 19 Greek populations, among the 35 different whitefly populations used for the whole analysis. Resistance factors scaled up to 207-, 4657- and 59-fold for imidacloprid, bifenthrin and spiromesifen, respectively. Molecular assays were used to investigate the frequency of known resistance mutations. A simple polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was developed for detecting the pyrethroid-resistant alleles r1 (mutation L925I) and r2 (mutation T929I) of the para-type voltage-gated sodium channel gene (VGSC). Both alleles were present at high frequencies (on average 65% and 33%, respectively) in 14 populations from Greece. The M918 L pyrethroid resistance mutation was not detected in any of the Greek populations. Sequencing and a Taqman allelic discrimination were used to monitor the frequency of the mutation E645K of the acetyl-coenzyme A carboxylase gene (ACC) recently linked to spiromesifen resistance. This mutation was detected in 20 of the 24 populations examined in ∼38% frequency among the 433 individuals tested. However, its association with the spiromesifen resistance phenotype was not confirmed in the Greek populations. Finally, two homologues of the CYP6CM1 Bemisia tabaci P450, the known neonicotinoid metabolizer, were found upregulated in two T. vaporariorum neonicotinoid-resistant populations; they were both functionally expressed in Escherichia coli, but the recombinant proteins encoded did not metabolize those neonicotinoid insecticides tested.. The development of simple diagnostics and their use alongside classical and molecular techniques for the early detection of resistant populations are of great importance for pest management strategies. The practical implications of our results are discussed in light of whitefly control. © 2017 Society of Chemical Industry.

Topics: Animals; Cytochrome P450 Family 6; Female; Greece; Hemiptera; Insect Control; Insect Proteins; Insecticide Resistance; Insecticides; Male; Neonicotinoids; Nitro Compounds; Pyrethrins; Spiro Compounds

One method for controlling the Asian citrus psyllid (ACP) Diaphorina citri Kuwayama, the vector of the putative causal agent of Huanglongbing, uses the parasitoid Tamarixia radiata (Waterston). However, the general intensive use of insecticides has reduced the numbers of this parasitoid. This study evaluated the effect of the residual action of 24 insecticides on T. radiata and also determined the differential toxicity of insecticides to D. citri and T. radiata, using three bioassays. In the first, when adults of the parasitoid were exposed to residues of the 24 insecticides, ten were considered short-life (class 1), six slightly persistent (class 2), five moderately persistent (class 3), and three insecticides were considered persistent (class 4), under the IOBC/WPRS classification system. The second bioassay evaluated the sublethal concentrations of the persistent insecticides (formetanate, dimethoate, spinosad). Increasing the concentrations of the insecticides increased the number that were classified as persistent. In the third bioassay, evaluation of the differential toxicity of eight insecticides to the ACP and the parasitoid showed that chlorpyrifos and bifenthrin were more harmful to T. radiata. Therefore, these two insecticides are not recommended for application at the time of parasitoid release. Cypermethrin, imidacloprid, and dimethoate caused higher mortality of D. citri and are most often recommended in IPM programs. The choice of an insecticide for the control of citrus pests must be made with care, aiming to preserve the natural enemies in the ecosystem, and thereby contribute to the success of biological control.

Topics: Animals; Biological Control Agents; Carbamates; Chlorpyrifos; Dimethoate; Hemiptera; Hymenoptera; Insecticides; Neonicotinoids; Nitro Compounds; Pyrethrins

To assess the toxicity of bifenthrin and four mixtures of insecticides to tarnished plant bug, we used an insecticide dip method of green bean to treat adults of a laboratory colony; mortality was assessed after 48 h. LC50s for imidacloprid, bifenthrin, acephate, thiamethoxam, and dicrotophos were 0.12, 0.39, 0.62, 0.67, and 3.96 ppm, respectively. LC75s for imidacloprid, bifenthrin, acephate, thiamethoxam, and dicrotophos were 0.61, 4.22, 5.10, 2.65, and 7.86 ppm, respectively. Based on the LC50s and LC75s, dicrotophos was much less toxic than the other chemicals tested. PoloMix software was used to determine syngerism, antagonism, or addition effects of the mixtures. Three out of four analyses of the joint action of bifenthrin plus imidacloprid or acephate or dicrotophos showed that toxicity was not independent and not correlated. For bifenthrin plus dicrotophos, observed mortality was greater than expected mortality at most concentrations suggesting synergism. Mixtures of bifenthrin plus imidacloprid and bifenthrin plus acephate showed observed mortality significantly less than expected, suggesting antagonism. LC50s for bifenthrin plus dicrotophos, acephate, imidacloprid, and thiamethoxam were 0.38, 1.06, 0.17, and 0.26 ppm, respectively. LC75s for bifenthrin plus dicrotophos, acephate, imidacloprid, and thiamethoxam were 13.61, 13.18, 0.67, and 0.80 ppm, respectively. Based on the LC50s and LC75s, bifenthrin plus acephate was 3- to 10-fold less toxic than the other chemicals tested. Bifenthrin plus acephate is frequently used in tank mixes to control tarnished plant bug and other cotton pests, and the effectiveness of each individual chemical appears to be reduced in one to one ratio mixtures.

Topics: Animals; Heteroptera; Insecticide Resistance; Insecticides; Neonicotinoids; Nitro Compounds; Organophosphorus Compounds; Organothiophosphorus Compounds; Oxazines; Phosphoramides; Pyrethrins; Thiamethoxam; Thiazoles

Amblyseius cucumeris (Oudemans) is a beneficial non-target arthropod (NTA) and a key predator of tetranychid mites in integrated pest management (IPM) programs across China. Evaluating the toxic effects of insecticides on such predatory mites is essential for the success and development of IPM. We tested six insecticides to determine the risk of neonicotinoid insecticide toxicity to predatory mites, using the 'open glass plate method' and adult female A. cucumeris in a "worst case laboratory exposure" scenario. A 48-h toxicity test was performed using the hazard quotient (HQ) approach to evaluate the risk of each insecticide. The LR

Topics: Animals; Female; Guanidines; Insecticides; Malathion; Mites; Neonicotinoids; Nitro Compounds; Pest Control; Pyrethrins; Thiamethoxam

The Asian citrus psyllid, Diaphorina citri Kuwayama, is one of the most damaging pests of citrus-producing regions throughout the world. The use of insecticides is the main strategy for controlling psyllid and has increased year by year. In this study, four field populations of D. citri were evaluated for resistance to nine different insecticides using the leaf-dip method. The results showed that the highest level of resistance for D. citri was found in imidacloprid with a resistance ratio of 15.12 in the Zengcheng population compared with the laboratory susceptible population. This was followed by chlorpyriphos (6.47), dinotefuran (6.16), thiamethoxam (6.04), lambda-cyhalothrin (4.78), and bifenthrin (4.16). Piperonyl butoxide (PBO) and triphenyl phosphate (TPP) showed significant synergism on imidacloprid effects in the Zengcheng population (3.84- and 2.46-fold, respectively). Nevertheless, diethyl maleate (DEM) had no synergism on imidacloprid. Biochemical enzyme assays suggested that general esterase, glutathione S-transferase and cytochrome P450 monooxygenase activities were higher in the field-collected populations than in the laboratory susceptible population. However, glutathione S-transferase may play a minor role in the resistance of adult D. citri to insecticides. At the molecular level, resistance of D. citri to imidacloprid is mainly related to the increased expression of CYP4C68 and CYP4G70 (>5-fold).

Topics: Animals; China; Chlorpyrifos; Citrus; Guanidines; Hemiptera; Insecticide Resistance; Insecticides; Neonicotinoids; Nitriles; Nitro Compounds; Pyrethrins; Thiamethoxam

High tunnels are large protective structures used for season extension of many crops, including raspberries. These structures are often covered in plastic films to reduce and diffuse ultraviolet light transmission for pest and disease control, but this may also affect the photodegradation and efficacy of pesticides applied under these tunnels. We compared the residue levels of ten insecticides under three tunnel plastics with varying levels of UV transmission and open field conditions. Raspberry plants placed in research-scale tunnels were treated with insecticides and residues on fruit and foliage were monitored for one or two weeks in early 2015 and early and late 2016. Plastics that reduce UV transmission resulted in 50% greater residues of some insecticides compared to transparent plastics, and 60% compared to uncovered tunnels. This increased persistence of residues was evident within 1 day and remained consistently higher for up to 14 days. This pattern was demonstrated for multiple insecticides, including bifenthrin, esfenvalerate, imidacloprid, thiamethoxam, and spinosad. In contrast, the insecticide malathion degraded rapidly regardless of the plastic treatment, indicating less sensitivity to photodegradation. Bioassays using insecticide-treated leaves that were under UV-blocking plastic revealed higher mortality of the invasive fruit pest, Drosophila suzukii, compared to leaves that were uncovered. This indicates that the activity of pesticides under high tunnels covered in UV-reducing plastics may be prolonged, allowing for fewer insecticide applications and longer intervals between sprays. This information can be used to help optimize pest control in protected culture berry production.

Topics: Animals; Crops, Agricultural; Drug Combinations; Insect Control; Insecticides; Longevity; Macrolides; Malathion; Neonicotinoids; Nitriles; Nitro Compounds; Oxazines; Pesticide Residues; Pyrethrins; Rubus; Thiamethoxam; Thiazoles; Ultraviolet Rays

The parasitoid Ageniaspis citricola Longvnovskaya is a main biological control agent of the citrus leafminer Phyllocnistis citrella Stainton, an insect pest that causes considerable damage to citrus worldwide. However, the use of pesticides to control arthropod pests can reduce the effectiveness of parasitoids and disrupt integrated pest management in citrus groves. This study evaluated the impact on A. citricola of five insecticides that are used to control arthropod pests in citrus. Our results indicated that imidacloprid, chlorpyrifos, bifenthrin and β-cyfluthrin were harmful (mortality >89 %) to A. citricola adults; whereas abamectin did not cause significant mortality and was considered harmless to the parasitoid. In addition to causing high mortality, imidacloprid and bifenthrin were considered moderately persistent, because they caused <25 % mortality to 17 and 24 days after spraying (DAS), respectively. Chlorpyrifos and β-cyfluthrin were considered slightly persistent (mortality <25 %, 7 DAS). Although abamectin was considered harmless to A. citricola adults, had a short life (mortality <25 %, 3 DAS), and did not significantly affect the parasitism rate, the number and viability of pupae, or the longevity of A. citricola, this insecticide significantly reduced the proportion of females in the progeny compared to the control treatment. Therefore, semi-field and field studies that consider demographic parameters are needed to evaluate the impacts of these insecticides on the A. citricola parasitoid.

Topics: Animals; Chlorpyrifos; Citrus; Hymenoptera; Imidazoles; Insecticides; Ivermectin; Lepidoptera; Neonicotinoids; Nitriles; Nitro Compounds; Pest Control; Pyrethrins; Toxicity Tests

Lethal and sublethal effects of insecticides on target and non-target arthropods are a concern of pest management programs. Cycloneda sanguinea, Orius insidiosus and Chauliognathus flavipes are important biological control agents for aphids, whitefly, lepidopterus eggs, thrips and mites. All three test species were subjected to a toxicity study using the insecticides acephate, bifenthrin, chlorantraniliprole, chlorpyrifos, deltamethrin, imidacloprid, and thiamethoxam. Experiments were done in the lab and field. In the laboratory we evaluated the mortality and sublethal effects of the concentration that killed 20% of the population (LC20) on feeding, repellence and reproduction of the species tested. The lethal effects of these insecticides at the recommended doses was evaluated in the field. Concentration-response bioassays indicated chlorantraniliprole had the lowest toxicity, while chlorpyrifos and acephate were the most toxic. Test species exposed to filter paper surfaces treated with pyrethroids, neonicotinoids and organophosphates were repelled. On the other hand, test species were not repelled from surfaces treated with chlorantraniliprole. Chlorantraniliprole therefore seemed to be the least dangerous insecticide for these three beneficial arthropod test species.

Topics: Animals; Biological Control Agents; Chlorpyrifos; Coleoptera; Feeding Behavior; Female; Heteroptera; Imidazoles; Insecticides; Male; Neonicotinoids; Nitriles; Nitro Compounds; Organothiophosphorus Compounds; ortho-Aminobenzoates; Oxazines; Phosphoramides; Pyrethrins; Reproduction; Thiamethoxam; Thiazoles

Elevated levels of insecticides detoxifying enzymes, such as esterases, glutathione S-transferases (GSTs), and cytochrome P-450 monooxygenases, act in the resistance mechanisms in insects. In the present study, levels of these enzymes in the insecticide-resistant ground spider Pardosa sumatrana (Thorell, 1890) were compared with a susceptible population (control) of the same species. Standard protocols were used for biochemical estimation of enzymes. The results showed significantly higher levels of nonspecific esterases and monooxygenases in resistant spiders compared to controls. The activity of GSTs was lower in the resistant spiders. Elevated levels of nonspecific esterases and monooxygenases suggest their role in metabolic resistance in P. sumatrana. The reduced levels of total protein contents revealed its possible consumption to meet energy demands.

Topics: Animals; Cytochrome P-450 Enzyme System; Esterases; Glutathione Transferase; Imidazoles; Inactivation, Metabolic; Insect Proteins; Insecticide Resistance; Insecticides; Neonicotinoids; Nitro Compounds; Pakistan; Pyrethrins; Spiders

Megacopta cribraria F. (Hemiptera: Plataspidae), the kudzu bug, is an invasive insect pest of U.S. soybean. At present, insecticide application is the primary and most effective control option for M. cribraria In this study, the potential effects of sublethal and low-lethal concentrations (LC10 and LC40) of three common insecticides on key biological traits and acetylcholinesterase (AChE) activity of the treated nymphal stage of insect were assessed. The results show that the sublethal concentration of imidacloprid significantly reduced adult emergence rate of M. cribraria A low-lethal concentration of imidacloprid significantly increased nymphal development time, but significantly decreased adult emergence rate and adult longevity. Both sublethal and low-lethal concentrations of acephate caused an increase in nymphal development time and a reduction in adult emergence rate and adult longevity. Fecundity of females was significantly reduced only by exposure to low-lethal concentrations of acephate. Sublethal and low-lethal concentrations of bifenthrin increased nymphal development time, but significantly decreased adult emergence rate. In addition, we found that the AChE activity of M. cribraria was significantly increased only by LC40 imidacloprid, but strongly inhibited by acephate.

Topics: Acetylcholinesterase; Animals; Heteroptera; Imidazoles; Insecticides; Neonicotinoids; Nitro Compounds; Nymph; Organothiophosphorus Compounds; Phosphoramides; Pyrethrins

A number of 100 Pu-erh tea samples from the 2013 harvest in Yunnan Province (China) were analysed for 74 pesticides. A total of 11 pesticides were detected. At least one pesticide was detected in 56% of the samples. None of these samples contained the 74 monitored pesticides at concentrations above the Chinese maximum residual levels. Imidacloprid, bifenthrin and acetamiprid were most frequently found, with percentages of 53%, 46% and 31%, respectively. These were also the top three pesticides with maximum concentrations of 140, 246 and 672 μg kg⁻¹, respectively. Residual levels of the monitored pesticides showed no significant correlation with the production time or area of Pu-erh tea. Whereas a high incidence of pesticide residues was detected in Pu-erh tea, the contamination levels observed do not pose any serious health risks.

Topics: Camellia sinensis; China; Crops, Agricultural; Diet; Fermentation; Food Contamination; Food Inspection; Food Storage; Guidelines as Topic; Humans; Imidazoles; Insecticides; Neonicotinoids; Nitro Compounds; Pesticide Residues; Plant Leaves; Pyrethrins; Pyridines; Risk Assessment; Spatio-Temporal Analysis; Tea

Lambda-cyhalothrin, a sodium channel modulator insecticide, has been used frequently for the control of house flies, Musca domestica L. (Diptera: Muscidae) worldwide, including Pakistan. This experiment was performed to determine the selection and assessment of lambda-cyhalothrin resistance evolution along with four other insecticides. After 26 generations of selection, the lambda-cyhalothrin-selected population developed 445-fold resistance to lambda-cyhalothrin compared to the susceptible population. There was low cross-resistance to bifenthrin and very low cross-resistance to methomyl, imidacloprid, and fipronil in the lambda-cyhalothrin-selected population compared to the field population (G1). Realized heritability (h (2)) of resistance to lambda-cyhalothrin, bifenthrin, methomyl, imidacloprid, and fipronil was 0.07, 0.05, 0.01, 0.08, and 0.08, respectively. The projected rate of resistance development revealed that if 90 % house flies were selected, then a tenfold increase in lethal concentration 50 occurred after 17, 20, 159, 13, and 14 generations for lambda-cyhalothrin (h (2) = 0.07, slope = 2.09), bifenthrin (h (2) = 0.05, slope = 1.73), methomyl (h (2) = 0.01, slope = 2.52), imidacloprid (h (2) = 0.08, slope = 1.89), and fipronil (h (2) = 0.08, slope = 2.03), respectively. The results of our study concluded that the house fly has the potential to develop multiple insecticide resistances following continued selection pressure with lambda-cyhalothrin. This study will be helpful for assisting the development of resistance management strategies.

Topics: Animals; Female; Houseflies; Imidazoles; Insecticide Resistance; Insecticides; Male; Neonicotinoids; Nitriles; Nitro Compounds; Pakistan; Pyrazoles; Pyrethrins

Suisun Marsh, in northern San Francisco Bay, is the largest brackish marsh in California, and provides critical habitat for many fish species. Storm runoff enters the marsh through many creeks that drain agricultural uplands and the urban areas of Fairfield and Suisun City. Five creeks were sampled throughout a major storm event in February 2014, and analyzed for representatives of several major insecticide classes. Concentrations were greatest in creeks with urban influence, though sampling was done outside of the primary season for agricultural pesticide use. Urban creek waters reached maximum concentrations of 9.9 ng/l bifenthrin, 27.4 ng/l fipronil, 11.9 ng/l fipronil sulfone, 1462 ng/l imidacloprid, and 4.0 ng/l chlorpyrifos. Water samples were tested for toxicity to Hyalella azteca and Chironomus dilutus, and while few samples caused mortality, 70% of the urban creek samples caused paralysis of either or both species. Toxic unit analysis indicated that bifenthrin was likely responsible for effects to H. azteca, and fipronil and its sulfone degradate were responsible for effects to C. dilutus. These results demonstrate the potential for co-occurrence of multiple insecticides in urban runoff, each with the potential for toxicity to particular species, and the value of toxicity monitoring using multiple species. In the channels of Suisun Marsh farther downstream, insecticide concentrations and toxicity diminished as creek waters mixed with brackish waters entering from San Francisco Bay. Only fipronil and its degradates remained measurable at 1-10 ng/l. These concentrations are not known to present a risk based on existing data, but toxicity data for estuarine and marine invertebrates, particularly for fipronil's degradates, are extremely limited.

Topics: Amphipoda; Animals; Bays; Chlorpyrifos; Drainage, Sanitary; Ecosystem; Environmental Monitoring; Imidazoles; Insecticides; Neonicotinoids; Nitro Compounds; Pyrazoles; Pyrethrins; San Francisco; Waste Disposal, Fluid; Water Pollutants, Chemical; Wetlands

The tobacco whitefly Bemisia tabaci is one of the most devastating pests worldwide. Current management of B. tabaci relies upon the frequent applications of insecticides. In addition to direct mortality by typical acute toxicity (lethal effect), insecticides may also impair various key biological traits of the exposed insects through physiological and behavioral sublethal effects. Identifying and characterizing such effects could be crucial for understanding the global effects of insecticides on the pest and therefore for optimizing its management in the crops. We assessed the effects of sublethal and low-lethal concentrations of four widely used insecticides on the fecundity, honeydew excretion and feeding behavior of B. tabaci adults. The probing activity of the whiteflies feeding on treated cotton seedlings was recorded by an Electrical Penetration Graph (EPG). The results showed that imidacloprid and bifenthrin caused a reduction in phloem feeding even at sublethal concentrations. In addition, the honeydew excretions and fecundity levels of adults feeding on leaf discs treated with these concentrations were significantly lower than the untreated ones. While, sublethal concentrations of chlorpyrifos and carbosulfan did not affect feeding behavior, honeydew excretion and fecundity of the whitefly. We demonstrated an antifeedant effect of the imidacloprid and bifenthrin on B. tabaci, whereas behavioral changes in adults feeding on leaves treated with chlorpyrifos and carbosulfan were more likely caused by the direct effects of the insecticides on the insects' nervous system itself. Our results show that aside from the lethal effect, the sublethal concentration of imidacloprid and bifenthrin impairs the phloem feeding, i.e. the most important feeding trait in a plant protection perspective. Indeed, this antifeedant property would give these insecticides potential to control insect pests indirectly. Therefore, the behavioral effects of sublethal concentrations of imidacloprid and bifenthrin may play an important role in the control of whitefly pests by increasing the toxicity persistence in treated crops.

Topics: Animals; Carbamates; Chlorpyrifos; Feeding Behavior; Fertility; Hemiptera; Imidazoles; Insect Control; Insecticides; Neonicotinoids; Nervous System; Nitro Compounds; Pyrethrins; Toxicity Tests

Five formulated insecticides (lambda-cyhalothrin at 10 mg m⁻², bifenthrin at 50 mg m⁻², fipronil at 10 mg m⁻², fenitrothion at 50 mg m⁻², imidacloprid at 5 mg m⁻²) and one active ingredient (DDT at 500 mg m⁻²) were evaluated using a surface contact method against early and late instars and adults of two strains of the tropical bed bug, Cimex hemipterus (F.). Synergism of lambda-cyhalothrin and fipronil using piperonyl butoxide (PBO) was also assessed.. The order of susceptibility of different stages of bed bugs was as follows: early stage-lambda-cyhalothrin > bifenthrin = imidacloprid > fipronil > fenitrothion > DDT; late stage-lambda-cyhalothrin > bifenthrin > fenitrothion > imidacloprid > fipronil > DDT; adult-lambda-cyhalothrin > imidacloprid > bifenthrin > fenitrothion > fipronil > DDT. The late instars exhibited significantly higher LT₅₀ among the life stages. The addition of PBO to fipronil increased the susceptibility of the insects.. Lambda-cyhalothrin, bifenthrin, fenitrothion and fipronil at the recommended application rates were effective against C. hemipterus. Although imidacloprid demonstrated good initial response against C. hemipterus, the insects showed substantial recovery 72 h post-treatment. The late instars (fourth and fifth instars) should be used as the model for toxicological evaluation.

Topics: Animals; Bedbugs; DDT; Drug Synergism; Female; Fenitrothion; Imidazoles; Insecticides; Life Cycle Stages; Male; Neonicotinoids; Nitriles; Nitro Compounds; Pesticide Synergists; Piperonyl Butoxide; Pyrazoles; Pyrethrins; Time Factors; Tropical Climate

Mosquitoes characteristically feed on plant-derived carbohydrates and honeydew just after emergence and intermittently during their lives. Development of toxic baits focusing on this carbohydrate-seeking behavior may potentially contribute to localized control. In the present study, ten insecticides were fed to female Culex quinquefasciatus, Anopheles quadrimaculatus, and Aedes taeniorhynchus in a 10% sucrose solution. Active ingredients representative of five classes of insecticides (pyrethroids, phenylpyroles, pyrroles, neonicotinoids, and macrocyclic lactones) were selected for comparison with commercial formulations used to facilitate incorporation of active ingredients into aqueous sucrose solutions. Sucrose as a phagostimulant significantly enhanced mortality to toxicants. In general, the most effective active ingredients were fipronil, deltamethrin and imidacloprid, followed by spinosad, thiamethoxam, bifenthrin, permethrin, and cyfluthrin. The least effective ingredients were chlorfenapyr and ivermectin. For some of the ingredients tested, Cx. quinquefasciatus was the least susceptible species. One-day-old male Cx. quinquefasciatus were more susceptible than females; however, no differences existed between one- and seven-day-old mosquitoes. There were no differences in susceptibility between unfed and gravid ten-day-old female Cx. quinquefasciatus to bifenthrin. In conclusion, several pesticides from different classes of compounds have potential for use in development of toxic baits for mosquitoes.

Topics: Aedes; Animals; Anopheles; Culex; Culicidae; Drug Combinations; Female; Imidazoles; Insecticides; Ivermectin; Macrocyclic Compounds; Macrolides; Male; Mosquito Control; Neonicotinoids; Nitriles; Nitro Compounds; Oxazines; Permethrin; Pyrethrins; Pyrroles; Sucrose; Thiamethoxam; Thiazoles

Degradation and bioavailability of imidacloprid, fipronil, and bifenthrin applied at label rates ([AI], wt:wt in soil) in the loamy soil of Nebraska were determined over a 6-mo duration. Based on the calculated half-lives of the three termiticides, it was concluded that the degradation rate was lowest when a termiticide was applied at the highest label rate. Bioassays of Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) conducted at 8, 31, 65, 90, 135, 160, and 180 d posttreatment showed an inverse relationship between the LT90 values and the variable concentrations. At day 180, exposures to all the termiticide-treated soil samples (concentration x termiticide) resulted in 100% mortality of R. flavipes workers. However, lower LT90 values were observed for termites exposed to soils treated with highest label rates even when the treated soils were aged in the lab for 6 mo. This suggested a higher bioavailability of these three termiticides when applied at higher application rates. Termite mortality was fastest for bifenthrin followed by fipronil and imidacloprid.

Topics: Animals; Biological Availability; Environment; Half-Life; Imidazoles; Insecticides; Isoptera; Neonicotinoids; Nitro Compounds; Pesticide Residues; Pyrazoles; Pyrethrins; Soil

Laboratory and field studies were conducted to determine the persistence and efficacy of termiticides used as preconstruction treatments against subterranean termites. Bifenthrin (0.067%), chlorpyrifos (0.75%), and imidacloprid (0.05%) ([AI]; wt:wt) were applied to soil beneath a monolithic concrete slab at their minimum labeled rates. Soil samples were taken from three depths (0-2.5, 2.6-7.6, and 7.7-15.2 cm) at six sampling times (0, 3, 6, 9, 12 and 48 mo) from sites in Harrison and Oktibbeha counties in Mississippi. Residue analyses were conducted on the 0-2.5- and 2.6-7.5-cm depths, and bioassays were conducted using all three depths. In field studies, significant termiticide degradation occurred between sampling times 0 and 48 mo for all termiticides. At all sampling times, the top 2.5 cm of soil contained more termiticide than the other depths. Time to 50% dissipation of termiticide in the 0-2.5-cm depth was 9, 6, and 2 mo for bifenthrin, chlorpyrifos, and imidacloprid, respectively. Termite mortalities in contact bioassays remained high for bifenthrin and chlorpyrifos throughout the 48-mo sampling period; however, mortality of termites exposed to imidacloprid-treated soil dropped after the initial sampling. Termites readily penetrated all termiticide-treated soil in bioassays of 52-mm soil cores at 48 mo. Percentage of mortality in these bioassays was 15, 43, and 13 for bifenthrin, chlorpyrifos, and imidacloprid respectively.

Topics: Animals; Chlorpyrifos; Imidazoles; Insecticides; Isoptera; Mississippi; Neonicotinoids; Nitro Compounds; Pesticide Residues; Pyrethrins; Soil

Topics: Adsorption; Animals; Biological Availability; Chromatography, High Pressure Liquid; Imidazoles; Insecticides; Isoptera; Neonicotinoids; Nitro Compounds; Pyrazoles; Pyrethrins; Soil; Soil Microbiology; Soil Pollutants

The gall wasp Callirhytis cornigera (Osten Sacken) is a cynipid with alternating generations that produce large, woody stem galls and tiny blister-like leaf galls on pin oak, Quercus palustris Muenchhausen, in the United States. We tested 3 approaches to control the leaf-galling generation, and determined their impact on associated parasitoids and effectiveness in reducing numbers of new stem galls. First, trees were sprayed with bifenthrin or chlorpyrifos in late March to kill females emerging from stem galls before they oviposited into buds. Second, concentrated solutions of abamectin, imidacloprid, or bidrin were injected from pressurized containers into tree sapwood to control larvae developing in young leaf galls. Finally, systemic insecticides (acephate, abamectin, dimethoate, or imidacloprid) were sprayed at early leaf expansion (2 May) or to young, expanded leaves (17 May) to target larvae in leaf galls. Parasitoids, mostly eulophids, accounted for approximately 70% mortality of leaf-galling C. cornigera larvae on untreated trees. Whole-canopy sprays during C. cornigera emergence from stem galls reduced overall numbers of galled leaves and leaf galls. Trunk injections of bidrin or abamectin resulted in significant mortality of gall inhabitants, including parasitoids. However, neither of the aforementioned approaches significantly reduced numbers of new stem galls. Sprays of abamectin, dimethoate, or imidacloprid applied on 2 May caused high mortality of all gall inhabitants. There was no net benefit, however, because parasitism caused a similar reduction in C. cornigera survival on unsprayed shoots. Sprays applied later in leaf expansion had little impact on gall inhabitants. Of the treatments tested, bifenthrin sprays at bud break provided the greatest reduction in new leaf galls, whereas bidrin injections provided the greatest reduction in gall wasps emerging from galled leaves. This study suggests that gall wasp outbreaks are unlikely to be controlled by a single treatment, regardless of application method.

Topics: Animals; Chlorpyrifos; Hymenoptera; Imidazoles; Insecticides; Ivermectin; Larva; Neonicotinoids; Nitro Compounds; Organophosphorus Compounds; Plant Diseases; Plant Leaves; Pyrethrins; Quercus

Effects of irrigation regimen, quantity, and timing on the efficacy of three insecticides for controlling nymphs of the southern mole cricket, Scapteriscus borellii Giglio-Tos, and the tawny mole cricket, Scapteriscus vicinus Scudder, were studied on golf courses in 1997, 1998, and 1999. Two irrigation regimen tests using two rates of bifenthrin and lambda-cyhalothrin produced inconclusive results. Mole cricket damage ratings after the applications of bifenthrin (60 g [AI]/ha) and lambda-cyhalothrin (76 g [AI]/ha) were not significantly different among the four irrigation regimens (non-irrigation, irrigation before treatment, irrigation after treatment, and irrigation before and after treatment). Mole cricket damage rating after the application of bifenthrin (120 g [AI]/ha) under irrigation before and after irrigation was significantly better than those under other irrigation regimens at 14 and 21 d after treatment (DAT). Different irrigation quantity and irrigation timing (after insecticide treatment) did not significantly affect the performance of imidacloprid (434 g [AI]/ha) in the 1998 tests. However, the results from the 1999 test indicated that mole cricket damage ratings from the imidacloprid-treated plots were significantly different between 2 and 0.5 cm irrigation water after treatment at 21 and 28 DAT. Application of bifenthrin at a rate of 120 g (AI)/ha with 0.5 cm of irrigation water after treatment resulted in significantly lower mole cricket damage ratings than those of 1.0 and 2.0 cm of irrigation water after treatment at 30 DAT only in the 1998 test. Bifenthrin with irrigation at 1 h after insecticide treatment provided better mole cricket control than that of irrigation at 5 min after treatment at 30 DAT only in the 1998 test. Mole cricket damage ratings after application of bifenthrin were not significantly different between either irrigation quantity treatment or irrigation timing treatment in the 1999 tests. Possible effects of application timing, environmental conditions, irrigation practice, and insecticide physical properties on the results are discussed.

Topics: Agriculture; Animals; Golf; Gryllidae; Imidazoles; Insect Control; Insecticides; Neonicotinoids; Nitriles; Nitro Compounds; Poaceae; Pyrethrins