摘要:

AbstractA simple rapid bioassay is described for the determination of biologically available bromacil residues in soils. A clear aqueous extract was made from a soil fortified with a known amount of the herbicide, and similar extracts were made from samples of soil taken from plots that had been sprayed with a bromacil formulation at a rate of 4 kg ha−1. Samples of these extracts were added to a suspension of the unicellular green alga Selenastrum capricornutum. The net photosynthetic oxygen production by the alga was then measured using an oxygen electrode. The results were expressed as a percentage of the oxygen production by a control suspension. The concentration of biologically available bromacil was determined by reference to a previously established dose‐response curve of the percentage reduction in oxygen production against bromacil concentration. The accuracy of this bioassay was determined by comparing the results with those obtained using capillary gas‐liquid chromatography. The results obtained by the two different methods showed good agre

ISSN:0031-613X    

DOI:10.1002/ps.2780150502

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSurveys of lettuce, produced commercially in England and Wales, were carried out during the years 1977–82 to determine residues of inorganic bromide ion, following soil sterilisation with bromomethane. Lettuce grown on unfumigated soil contained less than 10 mg bromide ion kg−1, while most lettuce grown on bromomethane‐fumigated soil were found to contain higher levels of bromide ion, with a proportion in excess of 1000 mg kg−1. The accumulation of bromide ion appeared to be related to the interval between soil fumigation and planting, and also to the frequency of bromomethane application to the soil. A limited amount of data is presented on the levels of bromide ion in imported

ISSN:0031-613X    

DOI:10.1002/ps.2780150503

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractTwo structurally related organophosphorous insecticides, dichlorvos and trichlorfon, and their main metabolite dichloroacetaldehyde, were assayed for their ability to induce DNA repair, detected as unscheduled DNA synthesis in human epithelial‐like cell (EUE) cultures in vitro. A dose‐response relationship was found for treatment with the two pesticides, but negative results were obtained with dichloroacetaldehyde. Tests for induction of gene mutation, as ouabain resistance in Chinese hamster cells (V79), failed to show any mutagenic activity by these compou

ISSN:0031-613X    

DOI:10.1002/ps.2780150504

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractStructure‐activity relationships were used to determine the physicochemical properties of DDT that are important in the inhibition of oligomycin‐sensitive mitochondrial ATPase activity of red coxal muscle tissue homogenates of the American cockroach (Periplaneta americana). The results were compared with structure‐activity relationships derived from toxicity values for houseflies (Musca domestica) and blowflies (Phormia regina), reported in the literature. Toxicity was found to be promoted by hydrophobicity and electron donation. Toxicity was concluded to be a route of action process involving the distribution and partitioning of insecticide to active sites and apart from them. Enzyme inhibition, in contrast to factors contributing to toxicity, was determined to be a mode of action process predicted by the lipophilic parameter (π) and the steric constant, van der Waals radii (VWR), and represents action upon a sterically sensitive, hydrophobic site in the membrane sector of mitochondrial

ISSN:0031-613X    

DOI:10.1002/ps.2780150505

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSome effects of the chitin synthesis inhibitor complex nikkomycin on oogenesis in the two‐spotted spider mite Tetranychus urticae were demonstrated by means of electron microscopy. Four main effects were evident, depending on the oogenetic stages. Nuclear defects, observed in oogonia and primary oocytes, included a widened nuclear envelope, the intermembranous spaces of which were filled with electron‐dense material, and the occurrence of small electron‐dense agglomerations and altered nucleoli inside the nuclei. Cytoplasmic defects occurred mainly in nurse cells and involved electron‐dense granular areas accompanied by mitochondria, and large cisternae and vesicles of rough endoplasmic reticulum. Yolk synthesis in oocytes could be inhibited, as shown by the lack of yolk droplets or the presence of abnormal yolk droplets. Both phases of egg shell synthesis were disturbed, resulting in an inhibition of egg deposition. Mechanisms based upon the oogenetic effects of the metabolite complex nikkomycin are di

ISSN:0031-613X    

DOI:10.1002/ps.2780150506

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThirty‐six thiosemicarbazones of methyl 2‐pyridyl ketone and of some other methyl ketones were tested on Dysdercus cingulatus, Drosophila melanogaster, Locusta migratoria, Aedes aegypti, Tenebrio molitor and Musca domestica. Several derivatives were toxic, delaying or preventing ecdysis. The structure‐activity relationship is discussed. The mode of action of these compounds appears to be different from that of juvenile hormones, anti‐juvenile hormones, or chitin biosynthesis inh

ISSN:0031-613X    

DOI:10.1002/ps.2780150507

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe disposition of the pyrethroid insecticide cypermethrin, (RS)‐a‐cyano‐3‐phenoxybenzyl (1RS)‐cis, trans‐3‐(2,2‐dichlorovinly)‐2, 2‐dimethylcyclopropane‐carboxylate, has been studied in male and female rats following a single toxic oral dose (200mg kg−1) of two radiolabelled forms ([14C‐benzyl] and [14C‐cyclopropyl]) of the insecticide. The bioaccumulation and elimination of14C‐benzyl‐labelled cypermethrin, following repeated administration at a sub‐toxic dose (2mg kg−1), has also been studied in male and female rats. Although, at the toxic dose, radioactivity from the two radiolabelled forms was rapidly eliminated in urine and faeces, the increased excretion in the faeces, over that for low doses, was evidence that absorption was incomplete. The major pathways of metabolism involved cleavage of the ester bond, with subsequent hydroxylation and glucuronidation of the cyclopropyl acid moieties, together with hydroxylation and sulphation of the 3‐phenoxybenzyl moiety. The absence of sex‐ or dose‐dependent changes was reflected by the constant proportions of these metabolites found in the urine. Constant levels of radioactivity in tissues were achieved rapidly, generally within the first week of repeated administration. Elimination was rapid on the cessation of dosing, although less rapid from the fat and skin. The material in the fat was mainly the cis‐isomers of cypermethrin, which were eliminated with a mean half‐life of 18.2 days,

ISSN:0031-613X    

DOI:10.1002/ps.2780150508

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe potential synergistic activities of chlordimeform, S,S,S‐tributyl phosphorotrithioate (DEF), and piperonyl butoxide were studied by exposing adults of the red flour beetle Tribolium castaneum (Herbst) to treated filter paper discs. Each of the chemicals was individually of low toxicity to T. castaneum. However, when tested in various combinations, chlordimeform: DEF (1:1 and 1:4) exhibited a strong synergistic interaction, but other pairs (chlordimeform: piperonyl butoxide, 1:4, or DEF: piperonyl butoxide, 1:4) exhibited no synergism. When tested at experimentally determined optimum ratios with the synthetic pyrethroid permethrin, synergism was observed for permethrin:chlordimeform (1:2) and for permethrin: DEF (1:2) but not for permethrin: piperonyl butoxide (1:2). The triple mixture permethrin:chlordimeform:DEF (1:2:2) was twice as toxic as permethrin:DEF (1:2) but only slightly more toxic than permethrin: chlordimeform (1:2). Although chlordimeform and DEF interact synergistically, and each synergises permethrin by unrelated mechanisms, these interactions were not expressed independently in a mixture of all three substances tested against T. castaneu

ISSN:0031-613X    

DOI:10.1002/ps.2780150509

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractPermethrin is not a repellent against horn flies Haematobia irritans (L.). The flies were able to land but not rest or feed on cattle treated with a spray or a pour‐on application of permethrin, because the insecticide had a quick toxic effect. During the 15 days after treatment, all of the 813 flies exposed to the steer treated with the spray, died without taking a blood meal. During the same period, all but two of the 1426 horn flies died when exposed to the steer treated with the pour‐on application, and only one of the living and seven of the dead horn flies had taken a blood m

ISSN:0031-613X    

DOI:10.1002/ps.2780150510

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractEmulsifiable concentrate formulations of WL‐85871 (‘Fastac’) at 10 and 20 g a.i. ha−1, parathion‐methyl (MEP) at 500 g a.i. ha−1, and phosalone at 1200 g a.i. ha−1were individually applied to flowering mustard during June and July 1982. The applications were made by tractor‐mounted boom‐and‐nozzle equipment to small plots in Normandy, France. Before each application, bee hives were placed adjacent to the mustard plots and fitted with either a pollen trap or a dead‐bee trap. The application of both dose rates of WL‐85871 and phosalone resulted in no increase in bee mortalities and no discernible effect on pollen collection or long‐term hive development. In contrast, the application of MEP resulted in substantial bee mortalities, reduced pollen collection and adversely affected hive development. Both dose rates of WL‐85871 caused a sharp decline in foraging activity immediately after application, followed by a return to normal activity within a few hours. A prolonged gradual reduction in foraging activity occurred throughout the afternoon period after the phosalone application; with MEP, foraging activity fell rapidly to a very low level and remained so for the rest of that day and the following day. It was concluded that the ground application of WL‐85871 at 10 and 20 g a.i. ha−1had no direct effect on honey bee survival and no observ

ISSN:0031-613X    

DOI:10.1002/ps.2780150511

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY