flubendiamide and chlorantranilipole

Diamide insecticides have emerged as one of the most promising new classes of insecticide chemistry owing to their excellent insecticidal efficacy and high margins of mammalian safety. Chlorantraniliprole and flubendiamide, the first two insecticides from this class, demonstrate exceptional activity across a broad range of pests in the order Lepidoptera. This chemistry has been confirmed to control insects via activation of ryanodine receptors which leads to uncontrolled calcium release in muscle. The high levels of mammalian safety are attributed to a strong selectivity for insect over mammalian receptors.

Topics: Animals; Benzamides; Insect Control; Insecticides; Lepidoptera; ortho-Aminobenzoates; Ryanodine; Ryanodine Receptor Calcium Release Channel; Sulfones

As the typical representatives of diamide insecticides, excessive exposure to flubendiamide and chlorantraniliprole for plants may inevitably pose threats to plant growth and food safety. However, the underlying toxic mechanisms remain unclear. Here, glutathione

Topics: Benzamides; Diamide; Glutathione Transferase; Insecticides; Molecular Docking Simulation; Oxidative Stress; Triticum

Tomato, Lycopersicon esculentum L. is grown widely as an important day-to-day demand vegetable. The crop is attacked by various polyphagous insect pests like tomato fruit borer, stink bug, cabbage looper, flea beetle, aphids, whitefly, two-spotted spider mite, etc., and oligophagous insects like leaf-miner, five-spotted hawkmoth, etc. To combat the damage and yield loss, various chemical insecticides were sprayed on tomatoes under field conditions. The residual pattern of insecticides like chlorantraniliprole, thiamethoxam, flubendiamide, and deltamethrin residues was studied following applications of chlorantraniliprole 18.5% SC (Coragen) @ 30 g a.i./ha, thiamethoxam 25% WG (Actara) @ 50 g a.i./ha, flubendiamide 39.35 M/M SC (Fame) @ 48 g a.i./ha and deltamethrin 2.8% EC (Decis 100) @ 12.5 g a.i./ha using Reverse Phase High-Performance Liquid Chromatography (RP-HPLC). Fruit samples were collected at 0 (1 h after application), 1, 2, 3, 5, 7 days and at harvest time. All the residues of insecticides such as chlorantraniliprole (0.09 mg kg

Topics: Benzamides; Fruit; Insecticides; Pesticide Residues; Soil; Solanum lycopersicum; Thiamethoxam

Diamide resistant phenotypes have evolved in the field and the resistance has been attributed to target-site mutations in some lepidopteran pests. In this study, we documented the resistance status of Chilo suppressalis to chlorantraniliprole during 2016-2018 in seven provinces of China. To investigate the possible role of target-site mutations as known from lepidopterans, we sequenced respective domains of the RyR gene of C. suppressalis with different levels of diamide resistance. The results revealed that I4758M (corresponding to I4790M in P. xylostella), Y4667D/C (numbered according to C. suppressalis), G4915E (corresponding to G4946E in P. xylostella), and one novel Y4891F (numbered according to C. suppressalis) RyR target-site mutations were present. The contribution of these mutations was further investigated by diamide toxicity bioassays with eight genome modified Drosophila melanogaster lines. The study showed that genome modified flies bearing the Y4667D mutation (corresponding to the Y4667D and I4758M simultaneous mutation in C. suppressalis) exhibited high resistance ratios to chlorantraniliprole (1542.8-fold), cyantraniliprole (487.9-fold) and tetrachlorantraniliprole (290.1-fold). The M4758I and G4915E simultaneous mutations (corresponding to single G4915E mutation in C. suppressalis) showed high resistance ratios to chlorantraniliprole (153.1-fold) and cyantraniliprole (323.5-fold), and relatively low resistance to flubendiamide (28.9-fold) and tetrachlorantraniliprole (25.2-fold). These findings suggest that multiple point mutations in RyR confer diamide resistance of C. suppressalis. The results contribute to a better understanding of insect diamide resistance mechanisms and provide insights on the impact of RyR target-site mutations in insects.

Topics: Amino Acid Sequence; Animals; Benzamides; CRISPR-Cas Systems; Drosophila melanogaster; Insect Proteins; Insecticide Resistance; Insecticides; Moths; Mutation; ortho-Aminobenzoates; Pyrazoles; Ryanodine Receptor Calcium Release Channel; Sequence Alignment; Sulfones

The effect of temperature on the toxicities of four diamide insecticides (chlorantraniliprole, cyantraniliprole, flubendiamide, tetraniliprole) against three lepidopteran insects (Helicoverpa armigera, Plutella xylostella, Athetis lepigone) were determined from 15 to 35 °C by exposing third-instar larvae to dip-treated cabbage leaf. The results indicated that increase in temperature led to an increase significantly and regularly in the toxicities of the four diamide insecticides against P. xylostella and H. armigera, but not for A. lepigone. The temperature coefficients (TCs) of the four diamide insecticides increased from 15 to 35 °C. Tetraniliprole for H. armigera (+825.83), chlorantraniliprole for P. xylostella (+315.65) and cyantraniliprole for H. armigera (+225.77) exhibited high positive TCs. For A. lepigone, temperature had a positively weak or no effect on the toxicities of most of the diamide insecticides from 20 to 30 °C, but a higher effect from 30 to 35 °C. In addition, the toxicities of chlorantraniliprole, cyantraniliprole and tetraniliprole all decreased from 15 to 20 °C. This study can guide pest managers in choosing suitable ambient field temperature when spraying diamide insecticides against lepidopteran insects.

Topics: Animals; Benzamides; Diamide; Insecta; Insecticides; Larva; Moths; ortho-Aminobenzoates; Pyrazoles; Sulfones; Temperature; Toxicity Tests

Topics: Animals; Benzamides; Binding Sites; Biological Assay; Fluorescent Dyes; Kinetics; Moths; ortho-Aminobenzoates; Pyrazoles; Reproducibility of Results; Ryanodine Receptor Calcium Release Channel; Sulfones

In this study, a new method for simultaneous determination of cyantraniliprole, chlorantraniliprole, tetrachlorantraniliprole, cyclaniliprole and flubendiamide in edible mushrooms by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) combined with a modified QuEChERS procedure. The samples were extracted using acetonitrile and then cleaned up by primary secondary amine (PSA) and octadecylsilane (C18). The determination of these insecticides was achieved in less than 5 min using an electrospray ionization source in positive mode (ESI+) for cyantraniliprole and chlorantraniliprole, while negative mode (ESI-) for tetrachlorantraniliprole, cyclaniliprole and flubendiamide. The linearities of the calibrations for all target compounds were acceptable (R

Topics: Agaricales; Benzamides; Chromatography, High Pressure Liquid; Diamide; Food Analysis; Insecticides; ortho-Aminobenzoates; Pyrazoles; Sulfones; Tandem Mass Spectrometry

Topics: Adsorption; Agriculture; Benzamides; Environmental Pollutants; Microplastics; Neonicotinoids; ortho-Aminobenzoates; Pesticides; Plastics; Soil; Soil Pollutants; Sulfones

The diamondback moth Plutella xylostella is a major destructive pest of Brassica worldwide. P. xylostella has evolved resistance to nearly all commercial insecticides used for its control, including the most recent chemical class, diamide insecticides. Several studies show that the G4946E and I4790M mutations of ryanodine receptor (RyR) are strongly associated with diamide resistance in insects. While the pivotal functional role of G4946E in conferring diamide resistance phenotype has confirmed by several studies in different species, no direct evidence has unambiguously confirmed the functional significance of the single I4790M mutation in diamide resistance. Here, we successfully constructed a knockin homozygous strain (I4790M-KI) of P. xylostella using CRISPR/Cas9 coupled with homology directed repair approach to introduce I4790M into RyR. When compared with the background susceptible IPP-S strain, the manipulated I4790M-KI strain exhibited moderate resistance to the phthalic acid diamide flubendiamide (40.5-fold) and low resistance to anthranilic diamides chlorantraniliprole (6.0-fold) and cyantraniliprole (7.7-fold), with no changes to the toxicities of indoxacarb and β-cypermethrin. Furthermore, the acquired flubendiamide resistance was inherited in an autosomally recessive mode and significantly linked with the I4790M mutation of RyR in this I4790M-KI strain. Our findings provide in vivo functional evidence for the causality of I4790M mutation of PxRyR with moderate levels of resistance to flubendiamide in P. xylostella, and support the hypothesis that the diamide classes have different interactions with RyRs.

Topics: Animals; Benzamides; Calcium Signaling; CRISPR-Cas Systems; Diamide; Gene Silencing; Genes, Insect; Insect Control; Insecticide Resistance; Insecticides; Moths; Mutation; ortho-Aminobenzoates; Pest Control; Pyrazoles; Ryanodine Receptor Calcium Release Channel; Sulfones

Chlorantraniliprole (CP) and flubendiamide (FD) are widely used in agriculture globally to control lepidopteran pests. Both insecticides target ryanodine receptors (RyRs) and promote Ca2+ leak from sarcoplasmic reticulum (SR) within insect skeletal muscle yet are purportedly devoid of activity toward mammalian RyR1 and muscle. RyRs are ion channels that regulate intracellular Ca2+ release from SR during physiological excitation-contraction coupling. Mutations in RYR1 genes confer malignant hyperthermia susceptibility (MHS), a potentially lethal pharmacogenetic disorder in humans and animals. Compared with vehicle control, CP (10 µM) triggers a 65-fold higher rate of Ca2+ efflux from Ca2+-loaded mammalian WT-RyR1 SR vesicles, whereas FD (10 µM) produces negligible influence on Ca2+ leak. We, therefore, compared whether CP or FD differentially influence patterns of high-affinity [3H]ryanodine ([3H]Ry) binding to RyR1 isolated from muscle SR membranes prepared from adult C57BL/6J mice expressing WT, homozygous C-terminal MHS mutation T4826I, or heterozygous N-terminal MHS mutation R163C. Basal [3H]Ry binding differed among genotypes with rank order T4826I ≫R163C∼WT, regardless of [Ca2+] in the assay medium. Both CP and FD (0.01-100 µM) elicited concentration-dependent increase in [3H]Ry binding, although CP showed greater efficacy regardless of genotype or [Ca2+]. Exposure to CP (500 mg/kg; p.o) failed to shift intolerance to heat stress (38°C) characteristic of R163C and T4826I MHS mice, nor cause lethality in WT mice. Although nM-µM of either diamide is capable of differentially altering WT and MHS RyR1 conformation in vitro, human RyR1 mutations within putative diamide N- and C-terminal interaction domains do not alter heat stress intolerance (HSI) in vivo.

Topics: Animals; Benzamides; Calcium; Dose-Response Relationship, Drug; Heat-Shock Response; Heterozygote; Homozygote; Male; Malignant Hyperthermia; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Mutation; ortho-Aminobenzoates; Protein Binding; Rabbits; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum; Sulfones

Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) is one of the major pests of solanaceous plants in South America. It is considered a great threat by the European and Mediterranean Plant Protection Organization due to the serious economic damage that it causes on tomato farms; therefore, controlling this pest is a challenging task in South America. Controlling N. elegantalis at the egg stage is the best way to prevent it from damaging crops; however, thorough studies about the effectiveness of chemicals on the different life stages of this insect pest are lacking. In this study, the effects of different chemical classes were evaluated on N. elegantalis adults, female oviposition behavior, larvae, eggs, and embryonic development. None of the tested insecticides demonstrated toxicity to the adults; however, the results showed that cartap hydrochloride affects oviposition behavior. Moreover, methomyl and cartap hydrochloride exhibited high toxicity against the eggs and larvae, with higher than 80% of mortality. These insecticides interrupted larval hatching and caused alterations in the chorion layer. Flubendiamide and deltamethrin demonstrated toxicity on N. elegantalis larvae; however, lufenuron, indoxacarb, methoxyfenozide, and chlorantraniliprole demonstrated low toxicity on both eggs and larvae, with lower than 70% of mortality. Fruit treated with cartap hydrochloride had a deterrent effect. The ovicidal activity revealed by methomyl and cartap hydrochloride might provide new approaches regarding insecticide effects on eggs. Methomyl, cartap hydrochloride, flubendiamide, and deltamethrin demonstrated toxicity on larvae. The evaluation of the chorion of the eggshell in this study has clarified the toxic effect of methomyl and cartap hydrochloride on eggs.

Topics: Animals; Benzamides; Female; Hydrazines; Insect Control; Insecticides; Juvenile Hormones; Larva; Lepidoptera; Methomyl; Nitriles; ortho-Aminobenzoates; Oviposition; Ovum; Oxazines; Pyrethrins; Solanum; Sulfones; Thiocarbamates

Diamondback moth, Plutella xylostella (L.; Lepidoptera: Plutellidae), is an important pest of crucifers worldwide. The extensive use of diamide insecticides has led to P. xylostella resistance and this presents a serious threat to vegetable production. We selected chlorantraniliprole (Rf) and flubendiamide (Rh) resistance strains of P. xylostella with resistance ratios of 684.54-fold and 677.25-fold, respectively. The Rf and Rh strains underwent 46 and 36 generations of lab-selection for resistance, respectively. Low cross resistance of Rh to cyantraniliprole was found. Cross resistance to chlorfenapyr, tebufenozid, and indoxacarb was not found in Rf and Rh strains. The P. xylostella ryanodine receptor gene (PxRyR) transcripts level in the Rf and Rh strains was up-regulated. Except for Rf34 and Rh36, PxRyR expression in all generations of Rf and Rh selection gradually increased with increasing resistance. Two resistant populations were field-collected from Guangzhou Baiyun (Rb) and Zengcheng (Rz) and propagated for several generations without exposure to any pesticide had higher PxRyR expression than the susceptible strain (S). In the S strain, PxRyR expression was not related to the resistance ratio. Gene sequencing found that the RyR 4946 gene site was glycine (G) in the S, Rf, and Rh strains, and was glutamate (E) with 70% and 80% frequency in the Rb and Rz populations, respectively. The 4946 gene site was substituted by valine (V) with the frequency of 30% and 20% in Rb and Rz populations, respectively. These results increase the understanding of the mechanisms of diamide insecticide resistance in P. xylostella.

Topics: Amino Acid Sequence; Animals; Benzamides; China; Insect Proteins; Insecticide Resistance; Insecticides; Larva; Moths; ortho-Aminobenzoates; Ryanodine Receptor Calcium Release Channel; Sequence Alignment; Sulfones

Diamide insecticides are used widely against lepidopteran pests, acting as potent activators of insect Ryanodine Receptors (RyRs) and thus inducing muscle contraction and eventually death. However, resistant phenotypes have recently evolved in the field, associated with the emergence of target site resistance mutations (G4946E/V and I4790M). We investigated the frequency of the mutations found in a resistant population of Tuta absoluta from Greece (G4946V ~79% and I4790M ~21%) and the associated diamide resistance profile: there are very high levels of resistance against chlorantraniliprole (9329-fold) and flubendiamide (4969-fold), but moderate levels against cyantraniliprole (191-fold). To further investigate functionally the contribution of each mutation in the resistant phenotype, we used CRISPR/Cas9 to generate genome modified Drosophila carrying alternative allele combinations, and performed toxicity bioassays against all three diamides. Genome modified flies bearing the G4946V mutation exhibited high resistance ratios to flubendiamide (91.3-fold) and chlorantraniliprole (194.7-fold) when compared to cyantraniliprole (5.4-fold). Flies naturally wildtype for the I4790M mutation were moderately resistant to flubendiamide (15.3-fold) but significantly less resistant to chlorantraniliprole (7.5-fold), and cyantraniliprole (2.3-fold). These findings provide in vivo functional genetic confirmation for the role and relative contribution of RyR mutations in diamide resistance and suggest that the mutations confer subtle differences on the relative binding affinities of the three diamides at an overlapping binding site on the RyR protein.

Topics: Amides; Animals; Benzamides; CRISPR-Cas Systems; Drosophila melanogaster; Greece; Insecticide Resistance; Insecticides; Moths; Mutation; ortho-Aminobenzoates; Pyrazoles; Ryanodine Receptor Calcium Release Channel; Sulfones

The rice stem borer, Chilo suppressalis Walker (Lepidoptera: Crambidae), is one of the most economically important pests of rice in Asia. Chemical control remains the most efficient primary means for controlling this pest.. Significant variations among field populations in their resistance to seven insecticides were observed. The populations exhibited LC. G4910E mutation might be involved in the resistance evolution of C. suppressalis to the diamides. An appropriate insecticide resistance management programme should be established to maintain the effectiveness of the insecticides and to ensure sustainable management. © 2016 Society of Chemical Industry.

Topics: Animals; Benzamides; China; Insecticide Resistance; Insecticides; Moths; ortho-Aminobenzoates; Oryza; Sulfones

Insect ryanodine receptors (RyR) are the molecular target-site for the recently introduced diamide insecticides. Diamides are particularly active on Lepidoptera pests, including tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae). High levels of diamide resistance were recently described in some European populations of T. absoluta, however, the mechanisms of resistance remained unknown. In this study the molecular basis of diamide resistance was investigated in a diamide resistant strain from Italy (IT-GELA-SD4), and additional resistant field populations collected in Greece, Spain and Brazil. The genetics of resistance was investigated by reciprocally crossing strain IT-GELA-SD4 with a susceptible strain and revealed an autosomal incompletely recessive mode of inheritance. To investigate the possible role of target-site mutations as known from diamondback moth (Plutella xylostella), we sequenced respective domains of the RyR gene of T. absoluta. Genotyping of individuals of IT-GELA-SD4 and field-collected strains showing different levels of diamide resistance revealed the presence of G4903E and I4746M RyR target-site mutations. These amino acid substitutions correspond to those recently described for diamide resistant diamondback moth, i.e. G4946E and I4790M. We also detected two novel mutations, G4903V and I4746T, in some of the resistant T. absoluta strains. Radioligand binding studies with thoracic membrane preparations of the IT-GELA-SD4 strain provided functional evidence that these mutations alter the affinity of the RyR to diamides. In combination with previous work on P. xylostella our study highlights the importance of position G4903 (G4946 in P. xylostella) of the insect RyR in defining sensitivity to diamides. The discovery of diamide resistance mutations in T. absoluta populations of diverse geographic origin has serious implications for the efficacy of diamides under applied conditions. The implementation of appropriate resistance management strategies is strongly advised to delay the further spread of resistance.

Topics: Amino Acid Sequence; Animals; Benzamides; Cloning, Molecular; DNA, Complementary; Insect Proteins; Insecticide Resistance; Insecticides; Moths; ortho-Aminobenzoates; Point Mutation; Ryanodine Receptor Calcium Release Channel; Sulfones

Predatory arthropods can be important for preventing insect pests from reaching damaging levels in soybean. However, the predator community can be compromised when pest control strategies include the application of broad-spectrum insecticides. The use of selective insecticides such as diamides could conserve predators while still providing necessary pest control. We evaluated two selective diamide insecticides, chlorantraniliprole and flubendiamide, and a broad-spectrum insecticide, lambda-cyhalothrin in combination with chlorantraniliprole, for impact on predators in soybean. We applied insecticides to field plots and documented predator abundance prior to and up to 3 wk postapplication using sticky card, beat sheet, and sweep net sampling methods. In sweep net samples, total predator abundance in plots treated with the selective insecticides was not significantly different from untreated control plots. For beat sheet samples, there were no significant differences in the abundance of total predators on any day postapplication between the selective diamide insecticides or the untreated control, but abundance decreased after application of lambda-cyhalothrin + chlorantraniliprole and did not recover. For sticky cards, there were no differences in predator abundance among treatments on any day postapplication. Over all, results showed that there were no significant differences in the abundance of total predators, Anthocoridae, Araneae, or Geocoridae after application of flubendiamide or chlorantraniliprole compared with the untreated control for up to 3 wk after application. All insecticides significantly decreased populations of lepidopteran pests compared with the untreated control, but only lambda-cyhalothrin + chlorantraniliprole reduced predatory arthropod abundance.

Topics: Animals; Benzamides; Glycine max; Insecta; Insecticides; Nitriles; ortho-Aminobenzoates; Pest Control, Biological; Predatory Behavior; Pyrethrins; Sulfones

Corn earworm, Helicoverpa zea (Boddie), is a significant pest of agroecosystems in the midsouthern and southeastern regions of the United States. These insects have developed resistance to, or inconsistent control has occurred with, most insecticide classes. With their unique mode of action, insecticides in the diamide class have become a key component in management of agriculturally important lepidopteran pests. In this study, field populations of H. zea were collected in the southern United States and compared to susceptible laboratory colonies to generate baseline concentration-mortality data. LC50 and LC90 values were generated for flubendiamide and chlorantraniliprole using neonates. To achieve equivalent levels of mortality, a higher concentration of flubendiamide was required compared to chlorantraniliprole. Flubendiamide LC50 values for H. zea ranged from 16.45 to 30.74 ng/ml, with a mean of 23.53 ng/ml. Chlorantraniliprole LC50 values for H. zea ranged from 2.94 to 4.22 ng/ml, with a mean of 3.66 ng/ml. Significant differences were observed for some field populations relative to the laboratory colony. For flubendiamide, five populations had greater LC50 values and two populations had lower LC50 values compared to the laboratory colony. For chlorantraniliprole, three populations had greater LC50 values and three populations had lower LC50 values compared to the laboratory colony. The response of these populations most likely represents natural variability among populations and does not indicate a significant shift in susceptibility of this species.

Topics: Animals; Benzamides; Insecticide Resistance; Insecticides; Larva; Lethal Dose 50; Moths; ortho-Aminobenzoates; Southeastern United States; Sulfones

Experiments were conducted in Mississippi from 2013 to 2015 to determine the systemic and residual efficacy of chlorantraniliprole and flubendiamide against corn earworm, Helicoverpa zea (Boddie), in soybean. Both insecticides were applied at V4 and R3. Ten leaves that were present at the time of application and 10 newly emerged leaves that were not present at the time of application were collected to measure residual and systemic efficacy, respectively. Ten pods were removed from each plot at R5.5. For all assays, corn earworm larvae were placed on plant material. Chlorantraniliprole appeared to provide systemic control of H. zea, but was dependent on soybean growth stage at the time of application. In the V4 experiment, chlorantraniliprole resulted in greater mortality than the control on new leaves at 7 d after treatment, but not at 14 d. In the R3 experiment, chlorantraniliprole resulted in greater than 90% mortality on new leaves at all evaluation intervals. Mortality of H. zea on new leaves was <17% for flubendiamide and was not different than the control. Both insecticides resulted in significant mortality of H. zea on leaves that were present at the time of application for at least 31 d after application. Chlorantraniliprole resulted in greater mortality than flubendiamide at 24 and 31 d. Neither insecticide resulted in mortality of H. zea feeding on reproductive structures. These results suggest that chlorantraniliprole moves to new vegetative structures but not to reproductive structures of soybean, and that flubendiamide does not move systemically.

Topics: Animals; Benzamides; Glycine max; Insecticides; Larva; Moths; ortho-Aminobenzoates; Pesticide Residues; Sulfones

Diamides, such as flubendiamide and chlorantraniliprole, belong to a new chemical class of insecticides that act as conformation-sensitive activators of insect ryanodine receptors (RyRs). Both compounds are registered for use against lepidopteran species such as the diamondback moth, Plutella xylostella, a notorious global pest of cruciferous crops. Recently acquired resistance to diamide insecticides in this species is thought to be due to a target-site mutation conferring an amino acid substitution (G4946E), located within the trans-membrane domain of the RyR, though the exact role of this mutation has not yet been fully determined. To address this we have cloned a full-length cDNA encoding the P. xylostella RyR and established clonal Sf9 cell lines stably expressing either the wildtype RyR or the G4946E variant, in order to test the sensitivity to flubendiamide and chlorantraniliprole on the recombinant receptor. We report that the efficacy of both diamides was dramatically reduced in clonal Sf9 cells stably expressing the G4946E modified RyR, providing clear functional evidence that the G4946E RyR mutation impairs diamide insecticide binding.

Topics: Animals; Benzamides; Caffeine; Calcium Signaling; Cloning, Molecular; Drug Tolerance; Gene Expression; Insect Proteins; Insecticides; Mutation, Missense; ortho-Aminobenzoates; Protein Binding; Ryanodine; Ryanodine Receptor Calcium Release Channel; Sf9 Cells; Spodoptera; Sulfones

Anthranilic and phthalic diamides exemplified by chlorantraniliprole (Chlo) or cyantraniliprole (Cyan) and flubendiamide (Flu), respectively, are the newest major chemotype of insecticides with outstanding potency, little or no cross resistance with other classes and low mammalian toxicity. They are activators of the ryanodine (Ry) receptor (RyR)-Ca(2+) channel, based on Ca(2+) flux and electrophysiology investigations. The goal of this study is to define species differences in the degree and mechanisms of diamide selective action by radioligand specific binding studies at the [(3)H]Ry, [(3)H]Chlo and [(3)H]Flu sites. The [(3)H]Ry site is observed in muscle of lobster, rabbit and four insect species (Musca domestica, Apis mellifera, Heliothis virescens and Agrotis ipsilon) whereas the [(3)H]Chlo site is evident in the four insects and the [(3)H]Flu site in only the two lepidoptera (Agrotis and Heliothis). [(3)H]Ry binding is significantly stimulated by Chlo, Cyan and Flu with the insects (except Flu with Musca) but not the lobster and rabbit. [(3)H]Chlo binding is stimulated by Ry and Flu in Musca and Apis but not in the lepidoptera, while Flu and Cyan are inhibitory. [(3)H]Flu binding is strongly inhibited by Chlo and Cyan in Agrotis and Heliothis. [(3)H]Chlo and [(3)H]Flu binding are not dependent on added Ca(2+) or ATP in Heliothis and Agrotis whereas the other radioligand-receptor combinations are usually enhanced by Ca(2+) and ATP. More generally, there are species differences in the Ry, Chlo and Flu binding sites of the RyR that may confer selective toxicity and determine target site cross resistance mechanisms.

Topics: Animals; Benzamides; Binding Sites; Insecta; Insecticides; Lepidoptera; Moths; ortho-Aminobenzoates; Rabbits; Ryanodine Receptor Calcium Release Channel; Sulfones

Chlorantraniliprole and flubendiamide belong to the new chemical class of diamide insecticides. High levels of resistance to chlorantraniliprole rapidly evolved in field populations of Plutella xylostella from southern China. An investigation was made of diamide cross-resistance, as well as inheritance, stability and metabolic mechanisms of chlorantraniliprole resistance in field populations of P. xylostella from southern China.. Three field populations of P. xylostella collected from southern China in 2011 showed high levels of cross-resistance between chlorantraniliprole (18-1150-fold) and flubendiamide (15-800-fold) when compared with a susceptible reference strain. Genetic analysis showed that chlorantraniliprole resistance in the ZC population was autosomal and incompletely recessive. In the absence of selection pressure, resistance to chlorantraniliprole in the ZC population declined from 2040-fold (G1 ) to 25-fold (G7 ). The ZC-R strain (derived by selection from ZC) exhibited 670-fold resistance to chlorantraniliprole, which is synergised by known metabolic inhibitors such as PBO, DEM and DEF at low levels.. Field-evolved resistance to chlorantraniliprole in P. xylostella confers strong cross-resistance to flubendiamide, so both compounds should be well separated and not alternated in resistance management strategies. High-level resistance to chlorantraniliprole in the ZC population was incompletely recessive and not stable. Metabolic detoxification was involved in chlorantraniliprole resistance in the ZC-R strain to some extent, but target-site resistance could not be excluded. © 2012 Society of Chemical Industry.

Topics: Animals; Benzamides; Biological Evolution; Female; Genetic Linkage; Inheritance Patterns; Insecticide Resistance; Insecticides; Male; Moths; ortho-Aminobenzoates; Pesticide Synergists; Sulfones

Radiolabeled anthranilic diamide insecticide [N-C(3)H(3)]chlorantraniliprole was synthesized at high specific activity. It was compared with phthalic diamide insecticide flubendiamide and [(3)H]ryanodine in radioligand binding studies with house fly muscle membranes to provide the first direct evidence with a native insect ryanodine receptor that the major anthranilic and phthalic diamide insecticides bind at different allosterically coupled sites, i.e., there are three distinct Ca(2+)-release channel targets for insecticide action.

Topics: Animals; Benzamides; Binding Sites; Calcium; Carbon; Insect Proteins; Insecta; Insecticides; Nitrogen; ortho-Aminobenzoates; Protein Binding; Ryanodine; Ryanodine Receptor Calcium Release Channel; Sulfones; Tritium

The modified excised leaf disc method was used to measure the effects of six insecticides on eggs, larvae, adults, and female fecundity of Galendromus occidentalis (Nesbitt) in a 'worst case laboratory exposure'. This study identified insecticides that would be recommended for tier II field evaluations for an integrated pest management program. Commercially formulated insecticides were applied with a thin-layer chromatography sprayer adjusted to 10.34 kPa (1.5 psi), at the recommended label concentrations in Canada. LC(50) values were estimated from aliquots above and below that concentration. Spinetoram and spirotetramat were toxic at label concentrations. The label concentration for spinetoram was 34.3-fold the LC(50) estimate (0.006 gL(-1)) and for spirotetramat the label concentration was 7.7-fold the LC(50) estimate (0.03 gL(-1)). Clothianidin was considerably less toxic and the label concentration was 0.15-fold the LC(50) estimate (2.29 gL(-1)). Estimates of LC(50) for novaluron and chlorantraniliprole could not be established. Both materials showed slight toxicity to at least one growth stage of the predator. Novaluron, clothianidin and chlorantraniliprole should be evaluated in the field for compatibility in IPM programs. Flubendiamide was harmless to all growth stages and it is recommended for inclusion in IPM programs without additional tier II field evaluations. Field evaluations with spinetoram and spirotetramat should be pursued only if alternatives are unavailable.

Topics: Acari; Animals; Benzamides; Female; Fertility; Guanidines; Insecticides; Laboratories; Larva; Macrolides; Male; Neonicotinoids; ortho-Aminobenzoates; Phenylurea Compounds; Risk Assessment; Sulfones; Thiazoles

The anthranilic and phthalic diamides, chlorantraniliprole (CAP) and flubendiamide (FLU), respectively, represent a new class of very effective insecticides that activate the ryanodine-sensitive intracellular calcium release channel (ryanodine receptor). This paper reports an analytical method for the simultaneous determination of the two insecticides on fruits and vegetables by liquid chromatography-electrospray tandem mass spectrometry operated in the positive and negative ionization switching mode. The two diamides were extracted with acetonitrile and separated on a Zorbax Column Eclipse XDB C8 (4.6 mm x 150 mm i.d., 3 microm) by isocratic elution with a mobile phase consisting of acetonitrile and water with 0.1% formic acid pumped at a flow rate of 0.4 mL/min. The diamides were selectively detected by multiple reaction monitoring for transitions of proton adduct precursor ions simultaneously: positive m/z 484.3-->285 for CAP, m/z 445.5-->169 for internal standard, and negative m/z 681.4-->253 for FLU. For CAP calibration in the positive mode was linear over a working range of 2 to 1000 microg/L with r > 0.992. The limit of detection (LOD) and limit of quantification (LOQ) for CAP were 0.8 and 1.6 microg/kg, respectively. For FLU in the negative mode the corresponding values were 1-1000 microg/L for linear working range, with r > 0.996 and 0.4 and 0.8 microg/L for LOD and LOQ, respectively. Moreover, the presence of interfering compounds in the fruit and vegetable extracts was found to be minimal. Due to the linear behavior of the MS detector response for the two analytes, it was concluded that the multiple reaction transitions of molecular ions in the ion-switching mode can be used for analytical purposes, that is, for identification and quantification of diamides in fruit and vegetable extracts at trace levels.

Topics: Benzamides; Chromatography, High Pressure Liquid; Fruit; Insecticides; ortho-Aminobenzoates; Spectrometry, Mass, Electrospray Ionization; Sulfones; Tandem Mass Spectrometry; Vegetables