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1.
Pymetrozine is the first and only substance from the group of azomethine pyridines, a novel class of insecticides. The spectrum of activity covers sucking pests such as aphids, whiteflies and planthoppers.Tests were carried out in the laboratory and under field conditions to evaluate its impact on beneficial arthropods.In laboratory tests it demonstrated full selectivity against predaceous Coleoptera, Heteroptera, Neuroptera and the predatory mite Typhlodromus pyri.Following a single application at 250/200g a.i./ha on cotton in Egypt and in the USA, the regular sampling of predators over a period of three weeks revealed a similar population development in the pymetrozine and the untreated control plots. On okra, a vegetable crop in Egypt, it suppressed populations of Aphis gossypii with two sprays at 100g a.i./ha for the whole observation period of 23 days. It also allowed the survival of predators.These positive features make pymetrozine an ideal component in situations where sucking pests have to be controlled and natural enemies can play a substantial role as complementary control tools. 相似文献
2.
A new sesquiterpene lactone, 7alpha,10alpha-epoxy-1alpha(H),5alpha(H)-guaia-3,11(13)-dien-8alpha,12-olide, was isolated from the leaves of Hedyosmum arborescens. The structure of this unusual 7,10-epoxy-guaianolide was determined by spectroscopic methods, particularly one- and two-dimensional 1H and 13C NMR. 相似文献
3.
Pymetrozine is the first and only substance from the group of azomethine pyridines, a novel class of insecticides. The spectrum of activity covers sucking pests such as aphids, whiteflies and planthoppers. Tests were carried out in the laboratory and under field conditions to evaluate its impact on beneficial arthropods. In laboratory tests it demonstrated full selectivity against predaceous Coleoptera, Heteroptera, Neuroptera and the predatory mite Typhlodromus pyri. Following a single application at 250/200?g a.i./ha on cotton in Egypt and in the USA, the regular sampling of predators over a period of three weeks revealed a similar population development in the pymetrozine and the untreated control plots. On okra, a vegetable crop in Egypt, it suppressed populations of Aphis gossypii with two sprays at 100?g a.i./ha for the whole observation period of 23 days. It also allowed the survival of predators. These positive features make pymetrozine an ideal component in situations where sucking pests have to be controlled and natural enemies can play a substantial role as complementary control tools. 相似文献
4.
A new approach is proposed for liquid/solid extraction of retinol and alpha-tocopherol from samples, using a disposable kieselguhr cartridge. The substitution of the mixture methanol-ethanol-n-butanol (4 + 3 + 1) for methanol in the alkaline hydrolysis solution makes it now possible to process fatty samples. Methanol is necessary to solubilize the antioxidant ascorbic acid, and a linear chain alcohol such as n-butanol is necessary to reduce the size of soap micelles so that they can penetrate into the kieselguhr pores. In comparisons of the proposed method with conventional methods on mineral premixes and fatty feedstuffs, recovery and accuracy are at least as good by the proposed method. Advantages are increased rate of determinations and the ability to hydrolyze and extract retinol and alpha-tocopherol together from the same sample. 相似文献
5.
C F Bourgeois P R George L A Cronenberger 《Journal of the Association of Official Analytical Chemists》1984,67(3):631-634
The proposed determination of alpha-tocopherol is a continuous flow method with fluorometric detection. The only cleanup necessary is the usual saponification. A solution of the unsaponifiable matter in isooctane is automatically assayed. Isooctane is the carrier solvent and extractions are inserted between steps. These steps are selective reactions which render the method very specific. The natural homologs of alpha-tocopherol (alpha-T) do not interfere in the determination. A procedure for blank assays allows selective inhibition of alpha-T conversions and measurement of interfering fluorescence. The method is highly sensitive, which allows the determination of alpha-T in very dilute solutions. This in turn suppresses matrix effects and renders the results reliable. The time interval between 2 peaks is 6 min, washing included, and it is possible to carry out 50 determinations per day (sample preparation not included). The system is robust and maintenance is easy. Parallel determinations of foods and feeds have been carried out with a conventional thin layer chromatographic method. 相似文献
6.
Bromination of the dichlorovinyl group of cypermethrin yielded a new compound which is a highly potent insecticide. This dibromo adduct has four asymmetric centres and therefore can exist as a mixture of 16 stereoisomers. To establish the influence of the absolute configuration at the chiral centres on the biological activities of these isomers, each of the isomers was isolated; their insecticidal activities against larvae of Heliothis virescens, and adult Calliphora erythrocephala and Blattella germanica were then determined and compared with those of (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (deltamethrin NRDC 161), of fenvalerate, and of the eight stereoisomers of cyper methrin. 相似文献
7.
Foltête Jean-Christophe Savary Paul Clauzel Céline Bourgeois Marc Girardet Xavier Sahraoui Yohan Vuidel Gilles Garnier Stéphane 《Landscape Ecology》2020,35(5):1053-1053
Landscape Ecology - In the original publication of the article, the sixth author name has been misspelt. The correct name is given in this Correction. The original article has been corrected. 相似文献
8.
Noubar J. Bostanian Gaétan Bourgeois Dominique Plouffe Charles Vincent 《Phytoparasitica》2014,42(1):13-22
In temperate regions, mirids may be occasional pests of vineyards where risk-averse growers use control measures. In that context, an optimal sampling scheme would allow determination of risk at minimal cost. A model driven by the accumulation of degree-days (DD) was developed to predict cumulative total captures of mirid nymphs (mainly the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois)) at 5%, 50%, and 95%. The model was based on 23 data sets collected over 4 years in three vineyards in southern Quebec. Lower and optimum temperatures for development were set at 10o and 32°C, based on experimental results and previous studies. Cumulative total captures at 5%, 50%, and 95% levels occurred, respectively, at 229, 331, and 479 DD for the first generation and 630, 806, and 1000 DD for the second generation. Paired t-tests and the forecasting efficiencies confirmed the reliability of the predictive model. The model indicated that monitoring for mirid nymphs of cool-climate in vineyards should be initiated at 200 and 500 DD calculated from 1 March for the first and second generations, respectively. Using the same lower and optimum temperatures for the development of mirids, another degree-day model was developed to predict grapevine phenological stages in relation to the modified Eichhorn-Lorenz system. Superimposing the mirid model over the grapevine model allows relating mirid total captures to grapevine phenological stages, and thus optimizing resources to monitor mirid populations in cool-climate vineyards. 相似文献
9.
D. Simpson M. Van Meirvenne E. Lück J. Rühlmann T. Saey J. Bourgeois 《European Journal of Soil Science》2010,61(4):469-478
Magnetic susceptibility is an important indicator of anthropogenic disturbance in the natural soil. This property is often mapped with magnetic gradiometers in archaeological prospection studies. It is also detected with frequency domain electromagnetic induction (FDEM) sensors, which have the advantage that they can simultaneously measure the electrical conductivity. The detection level of FDEM sensors for magnetic structures is very dependent on the coil configuration. Apart from theoretical modelling studies, a thorough investigation with field models has not been conducted until now. Therefore, the goal of this study was to test multiple coil configurations on a test field with naturally enhanced magnetic susceptibility in the topsoil and with different types of structures mimicking real archaeological features. Two FDEM sensors were used with coil separations between 0.5 and 2 m and with three coil orientations. First, a vertical sounding was conducted over the undisturbed soil to test the validity of a theoretical layered model, which can be used to infer the depth sensitivity of the coil configurations. The modelled sounding values corresponded well with the measured data, which means that the theoretical models are applicable to layered soils. Second, magnetic structures were buried in the site and the resulting anomalies measured to a very high resolution. The results showed remarkable differences in amplitude and complexity between the responses of the coil configurations. The 2‐m horizontal coplanar and 1.1‐m perpendicular coil configurations produced the clearest anomalies and resembled best a gradiometer measurement. 相似文献
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