pyrimidinones and imidacloprid

Triflumezopyrim, a novel mesoionic insecticide used to control planthoppers, is a potential substitute for imidacloprid. In this study, triflumezopyrim and imidacloprid residues in rice were determined using a quick, easy, cheap, effective, rugged, and safe procedure combined with ultra-high-performance liquid chromatography-tandem mass spectrometry. The limit of quantification of both triflumezopyrim and imidacloprid was 0.01 mg kg

Topics: Neonicotinoids; Nitro Compounds; Oryza; Pesticide Residues; Pyridines; Pyrimidinones; Risk Assessment

Nitenpyram is very effective in controlling Nilaparvata lugens (brown planthopper, BPH), and its resistance has been reported in field populations; however, the resistance mechanism remains unclear. In the present study, cross-resistance and resistance mechanisms in nitenpyram-resistant BPH were investigated. A resistant strain (NR) with a high resistance level (164.18-fold) to nitenpyram was evolved through successive selection for 42 generations from a laboratory susceptible strain (NS). The bioassay results showed that the NR exhibited cross-resistance to imidacloprid (37.46-fold), thiamethoxam (71.66-fold), clothianidin (149.17-fold), dinotefuran (98.13-fold), sulfoxaflor (47.24-fold), cycloxaprid (9.33-fold), etofenprox (10.51-fold) and isoprocarb (9.97-fold) but not to triflumezopyrim, chlorpyrifos and buprofezin. The NR showed a 3.21-fold increase in cytochrome P450 monooxygenase (P450) activity compared to that in the NS, while resistance was also synergized (4.03-fold) with the inhibitor piperonyl butoxide (PBO), suggesting a role of P450. Furthermore, the mRNA expression levels of cytochrome P450 (CYP) genes by quantitative real-time PCR results indicated that twelve P450 genes were significantly overexpressed in the NR strain, especially CYP6ER1 (203.22-fold). RNA interference (RNAi) suppression of CYP6ER1 through injection of dsCYP6ER1 led to significant susceptibility in the NR strain. The current study expands our understanding of the nitenpyram resistance mechanism in N. lugens, provides an important reference for integrated pest management (IPM), and enriches the theoretical system of insect toxicology.

Topics: Animals; Carbamates; Guanidines; Hemiptera; Insect Proteins; Insecticide Resistance; Neonicotinoids; Nitro Compounds; Pyrethrins; Pyridines; Pyrimidinones; RNA Interference; Thiazoles

In almost every ecosystem, ants (Hymenoptera: Formicidae) are the dominant terrestrial invertebrate group. Their functional value was highlighted by Wilson (1987) who famously declared that invertebrates are the "little things that run the world." However, while it is generally accepted that ants fulfil important functions, few studies have tested these assumptions and demonstrated what happens in their absence. We report on a novel large-scale field experiment in undisturbed savanna habitat where we examined how ants influence the abundance of other invertebrate taxa in the system, and affect the key processes of decomposition and herbivory. Our experiment demonstrated that ants suppressed the abundance and activity of beetles, millipedes, and termites, and also influenced decomposition rates and levels of herbivory. Our study is the first to show that top-down control of termites by ants can have important ecosystem consequences. Further studies are needed to elucidate the effects ant communities have on other aspects of the ecosystem (e.g., soils, nutrient cycling, the microbial community) and how their relative importance for ecosystem function varies among ecosystem types (e.g., savanna vs. forest).

Topics: Animals; Ants; Biodiversity; Grassland; Herbivory; Imidazoles; Insecticides; Neonicotinoids; Nitro Compounds; Population Dynamics; Principal Component Analysis; Pyrimidinones; Time Factors