cycloxaprid and imidacloprid

Paichongding (IPP) and cycloxaprid (CYC) have been effectively used as the alternative products of imidacloprid (IMI) against IMI-resistant insects and exhibit a great market potential. However, risk assessment of IPP and CYC for non-target organisms, especially ecological risk assessment for non-target aquatic organisms, is still lacking. Here, we predicted the toxicity and potential risks of IPP, CYC, and their transformation products (TPs) to hydrobionts. The results indicated that IPP and CYC could generate 428 and 113 TPs, respectively, via aerobic microbial transformation. Nearly half of the IPP TPs and nearly 41 % of the CYC TPs exhibited high or moderate toxicity to Daphnia or fish. Moreover, we found that IPP, CYC, and 80 TPs of them posed potential risks to aquatic ecosystems. Almost all harmful TPs contained a 6-chloropyridine ring structure, suggesting that this structure may be associated with the strong toxicity of these TPs to aquatic organisms, and these TPs (IPP-TP2 or CYC-TP2, IPP-TP197 or CYC-TP71, IPP-TP198 or CYC-TP72, and IPP-TP212 or CYC-TP80) may appear in aquatic environments as final products. The risks posed by these TPs to aquatic ecosystems require more attention. This study provides insights into the toxicity and ecological risks of IPP and CYC.

Topics: Animals; Aquatic Organisms; Ecosystem; Hydrolases; Insecticides; Neonicotinoids; Risk Assessment; Water Pollutants, Chemical

The melon aphid, Aphis gossypii Glover, is an important pest on various vegetables around the world and has developed resistance to neonicotinoids in fields. Cycloxaprid is a novel cis-nitromethylene configuration neonicotinoid insecticide that is different from trans-configuration neonicotinoids like imidacloprid and thiamethoxam. Herein, the cross-resistance to the other seven insecticides and fitness costs were investigated in the cycloxaprid-resistant A. gossypii strain (Cpd-R), which has developed 69.5-fold resistance to cycloxaprid. The results showed that the Cpd-R strain had very low levels of cross-resistance to imidacloprid (4.3-fold), acetamiprid (2.9-fold), thiamethoxam (3.7-fold), nitenpyram (6.1-fold), flupyradifurone (2.2-fold), and sulfoxaflor (4.5-fold), while it exhibited a cross-resistance to dinotefuran (10.6-fold). The fitness of the Cpd-R strain by life table analysis was only 0.799 compared to the susceptible strain (Cpd-S). This Cpd-R strain exhibited significantly reduction in fecundity, oviposition days, and developmental time of nymph stage compared to the Cpd-S strain. Moreover, the expression levels of some genes related to the development and reproduction, including EcR, USP, JHAMT, and JHEH were significantly up-regulated, while Vg was down-regulated in the Cpd-R strain. This study indicates that the Cpd-R strain possessed a certain fitness cost. The above research results are useful for rational application of cycloxaprid and implementing the appropriate resistance management strategy for A. gossypii.

Topics: Animals; Aphids; Cucurbitaceae; Female; Hemiptera; Heterocyclic Compounds, 3-Ring; Insecticide Resistance; Insecticides; Neonicotinoids; Nitro Compounds; Pyridines; Thiamethoxam

Unmanned aerial vehicles (UAVs) are a recently advanced aerial spraying technology. However, the median lethal number of droplets (LN. A small UAV and Potter spray tower (PST) were used to generate different size of droplets (Dv0.5 = 185 ± 5 and 43 ± 2 μm). The mortality of A. gossypii showed a droplet density-dependent process. At the concentration of 5 g L. Our results revealed that the r

Topics: Animals; Aphids; Heterocyclic Compounds, 3-Ring; Insecticides; Neonicotinoids; Nitriles; Nitro Compounds; Pyrethrins; Pyridines

Neonicotinoids, such as imidacloprid, are selective agonists of insect nicotinic acetylcholine receptors (nAChRs) used to control Nilaparvata lugens, a major rice insect pest. High imidacloprid resistance has been reported in N. lugens both in the laboratory and in the field. Cycloxaprid (CYC), an oxa-bridged cis-nitromethylene neonicotinoid, showed high insecticidal activity against N. lugens and low cross-resistance in imidacloprid-resistant strains and field populations.. Binding studies demonstrated that imidacloprid has two binding sites with different affinities (K. The high insecticidal activity, low cross-resistance and different binding properties on insect nAChRs of CYC show that it is a potential insecticide for the control of N. lugens and related insect pests, especially ones with high resistance to neonicotinoids. © 2018 Society of Chemical Industry.

Topics: Animals; Binding Sites; Female; Hemiptera; Heterocyclic Compounds, 3-Ring; Insect Proteins; Insecticide Resistance; Insecticides; Neonicotinoids; Nitro Compounds; Pyridines; Receptors, Nicotinic

Topics: Acetylcholinesterase; Animals; Catalase; Daphnia; Gene Expression; Guanidines; Heterocyclic Compounds, 3-Ring; Insecticides; Neonicotinoids; Nitro Compounds; Oxidative Stress; Pyridines; Reproduction; Superoxide Dismutase

Imidacloprid is a nicotinic acetylcholine receptor (nAChR) agonist with potent insecticidal activity. However, resistance to imidacloprid is a significant threat and has been identified in several pest species. Cycloxaprid with cis-configuration is a novel neonicotinoid insecticide, which shows high activity against imidacloprid-resistant pests. The LC50 of imidacloprid against the resistant Aphis gossypii was 14.33mgL(-1) while it was only 0.70mgL(-1) for the susceptible population, giving a resistance ratio of 20.47. In this imidacloprid-resistant population, a point mutation (R81T) located in the loop D region of the nAChR β1 subunit was found out. But this point mutation did not decrease the activity of cycloxaprid against A. gossypii. The LC50 of cycloxaprid was 1.05 and 1.36mgL(-1) for the imidacloprid-susceptible and imidacloprid-resistant populations, respectively. In addition, cycloxaprid provided better efficacies against resistant A. gossypii than imidacloprid in the fields. Although cycloxaprid was highly toxic to A. gossypii, it showed high selective activity between A. gossypii and its predominant natural enemies, Harmonia axyridis and Chrysoperla sinica. These results demonstrate that cycloxaprid is a promising insecticide against imidacloprid-resistant A. gossypii and suitable for the integrated pest management.

Topics: Animals; Aphids; Gossypium; Heterocyclic Compounds, 3-Ring; Imidazoles; Insect Control; Insecticide Resistance; Insecticides; Neonicotinoids; Nitro Compounds; Pyridines

Cycloxaprid (CYC) is a novel neonicotinoid prepared from the (nitromethylene)imidazole (NMI) analogue of imidacloprid. In this study we consider whether CYC is active per se or only as a proinsecticide for NMI. The IC50 values (nM) for displacing [(3)H]NMI binding are 43-49 for CYC and 2.3-3.2 for NMI in house fly and honeybee head membranes and 302 and 7.2, respectively, in mouse brain membranes, potency relationships interpreted as partial conversion of some CYC to NMI under the assay conditions. The 6-8-fold difference in toxicity of injected CYC and NMI to house flies is consistent with their relative potencies as in vivo nicotinic acetylcholine receptor (nAChR) inhibitors in brain measured with [(3)H]NMI binding assays. CYC metabolism in mice largely involves cytochrome P450 pathways without NMI as a major intermediate. Metabolites of CYC tentatively assigned are five monohydroxy derivatives and one each of dihydroxy, nitroso, and amino modifications. CYC appears be a proinsecticide, serving as a slow-release reservoir for NMI with selective activity for insect versus mammalian nAChRs.

Topics: Animals; Bees; Binding Sites; Heterocyclic Compounds, 3-Ring; Houseflies; Imidazoles; Insect Proteins; Insecticides; Kinetics; Male; Mice; Neonicotinoids; Nicotinic Antagonists; Nitro Compounds; Pyridines; Receptors, Nicotinic