bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isomers of sterol synthesis inhibitors: Fungicidal effects and plant growth regulator activities
Authors: Köller Wolfram 
Published: November 2006

AbstractThe chemical diversity of fungicides and antimycotics interfering with the C‐14 demethylation of fungal sterols indicates a rather high structural flexibility of the sterol binding site at the specific cytochrome P‐450 mixed‐function oxygenase. The structural flexibility, however, is opposed by a remarkable stereochemical selectivity. A similar, though not identical, stereochemical discrimination is observed with a group of plant growth regulators chemically related to the fungicidal demethylation inhibitors.The relationship between chemical structure and stereochemical requirements is discussed for both biological activities.
Pyrethroid insecticides derived from 2,2‐dimethyl‐3‐(3‐phenoxybenzyloxy)propanal
Authors: Svendsen Axel , Pedersen Lars‐Erik K. 
Published: November 2006

AbstractFourteen oxime ethers and eleven other unsaturated compounds derived from 2,2‐dimethyl‐3‐(3‐phenoxybenzyloxy)propanal were synthesised and their insecticidal activity against Musca domestica, Locusta migratoria, Dysdercus cingulatus, Aedes aegypti, Plutella xylostella, Drosophila melanogaster, Tetranychus urticae and Spodoptera littoralis tested. Structural variations including chain length, branching and unsaturation of the oxime ether O‐alkyl group and substituent exchange at the carbon‐carbon double bond of the unsaturated compounds were made in order to examine the structure‐activity relationship. All biological activities were compared with the activity of the ether pyrethroid MTI‐500.
Synthesis and insecticidal activity of lipophilic amides. Part 1: Introductory survey, and discovery of an active synthetic compound
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A. 
Published: November 2006

AbstractA group of naturally occurring isobutylamides and related compounds exhibit a range of biological properties including activity against insects. Their potential as a starting point for developing new insecticides, needed to control pests resistant to other classes of insecticides, is discussed, following an extensive survey of known structures and activities. Few of the known compounds were sufficiently active and well characterised to point to sound structure‐activity relationships, so synthetic analogues were examined. One of these [(2E,4E)‐N‐(2‐methylpropyl)‐6‐phenylhexa‐2,4‐dienamide] was sufficiently active, and prompted the investigations reported here and in subsequent papers in the series. Analogues of this compound designed to establish areas where structural variation is possible are also described.
Synthesis and insecticidal activity of lipophilic amides. Part 3: Influence of chain length and terminal group in N‐(2‐methylpropyl)‐2,4‐dienamides
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A. 
Published: November 2006

AbstractIncreasing the alkylene chain length in N‐(2‐methylpropyl)‐ω‐phenylalka‐2,4‐dienamides revealed in addition to the active compounds reported earlier a second peak of activity, but only against mustard beetles, with the tridecadienamide. Similar extension in the methyl‐terminated series gave much weaker peaks, at different lengths for the two test species. Results with terminal vinyl compounds were intermediate, and indicated a specific functional role in the lethal process for the terminal unsaturation, with a possible contribution to steric flexibility and physical property optimisation from the longer chains. Synthetic samples of pellitorine and pipercide, natural products to which insecticidal activity has been ascribed, were only very weakly active in the present tests, but compounds with other groups on the ends of chains nearer the optimum length were more active.
Influence of formulation on spray deposit patterns, dislodgeable and penetrated residues, and persistence characteristics of fenitrothion in conifer needles
Authors: Sundaram Kanth M. S. , Sundaram Alam 
Published: November 2006

AbstractThe influence of formulation on spray droplet spectra, deposit patterns, dislodgeable and penetrated residues, and persistence characteristics of fenitrothion in balsam fir needles was studied using three formulations containing different types of adjuvant. Spray was applied on to potted trees under controlled conditions in a laboratory chamber. Droplet size spectra and deposits were assessed using “Kromekote” cardlglass plate units. Foliar residues were measured by gas‐liquid chromatography.The formulation containing polymeric adjuvants provided significantly larger droplets and higher foliar residues than those containing surfactants and co‐surfactants. It also provided a higher ratio of dislodgeable‐to‐penetrated residues, and a slower initial rate of loss of fenitrothion. None of the formulations posed a long‐term persistence problem because only very low amounts remained on foliage at 42 days post‐treatment. The significance of these findings in terms of the possible increase in bioavailability of the pesticide via crawling contact is discussed.
Confirmation and quantification of pesticide residues by mass spectrometry
Authors: Gilbert John , Startin James R. , Crews Colin 
Published: November 2006

AbstractThe sensitivity and specificity of mass spectrometry makes this an attractive technique for the confirmation and quantification of trace levels of pesticide residues. Two applications of mass spectrometry are outlined, that of combined headspace gas chromatography (g.c.)/mass spectrometry (m.s.), for the analysis of volatile fumigants such as ethylene dibromide (EDB) in imported fruits and multi‐residue halogenated compounds in bran products, and that of quantitative g.c./m.s. for the determination of a range of organochlorine pesticide residues. The approach to setting‐up a capillary g.c. multiple ion monitoring programme is described, with emphasis on quantitative aspects, and in particular the use of stable isotope internal standards. This is illustrated with an example of the quantification of organochlorine pesticide residues in eggs.
Studies into the action of the diphenyl ether herbicides acifluorfen and oxyfluorfen. Part II: The interaction with photosynthetic electron transport reactions
Authors: Gillham David J. , Dodge Alan D. 
Published: November 2006

AbstractThe effects of acifluorfen and oxyfluorfen on photosynthetic electron transport reactions of pea chloroplasts were compared with those induced by paraquat and monuron. Monuron inhibited electron flow between photosystems I and II, and paraquat acted as an electron acceptor for photosystem I, promoting superoxide formation by illuminated chloroplasts. Neither acifluorfen nor oxyfluorfen at concentrations up to 50 μM affected non‐cyclic electron flow or promoted superoxide formation. Both herbicides were shown to repress ferredoxin‐dependent NADP+ reduction by illuminated chloroplasts. Further experiments showed that, in the presence of ferredoxin‐NADP+ reductase and chloroplast membranes maintained in the dark, p‐nitro diphenyl ether (DPE) herbicides promoted the rate of ferredoxin‐dependent oxidation of NADPH, implying that these herbicides can accept electrons from reduced ferredoxin. The interaction between acifluorfen, ferredoxin and chloroplast membranes was examined further by following the effect of this herbicide on the peroxidation of illuminated thylakoids. Lipid peroxidation was promoted by acifluorfen, although this effect was abolished if thylakoids were washed prior to use. The effect of washing could be reversed by adding exogenous ferredoxin. These data demonstrate that interaction of DPE herbicides with photosynthetic electron transport in the vicinity of ferredoxin is necessary for light‐dependent herbicide activation.
Influence of composition of nutrient medium on the metabolism of chlortoluron in plant‐cell suspension cultures
Authors: Cole David J. , Owen W. John 
Published: November 2006

AbstractThe herbicide chlortoluron readily underwent oxidative metabolism in suspension cultures of cotton and maize. Major attack in cotton cells was by stepwise N‐demethylation followed by relatively slow ring‐methyl hydroxylation. The most prominent single metabolites seen after 1 day and 7 days were 3‐(3‐chloro‐p‐tolyl)urea and its benzyl alcohol analogue, respectively. In maize cells, ring‐methyl hydroxylation was apparently the preferred mode of metabolism. Only low amounts of the demethylated derivatives of chlortoluron were evident, and the major residues present at both 2 days and 7 days were the benzyl alcohol derivative of chlortoluron and 3‐(3‐chloro‐4‐hydroxymethylphenyl)‐1‐methylurea. In both species, a substantial proportion of the free ‘phase 1’ metabolites was initially expelled to the medium, but at later times, these were found largely within the cell as polar conjugates.Two approaches were used to examine the influence of the composition of the medium on metabolism. Firstly, cells of both species were grown in four different nutrient media, which were selected to give variation in the organic nutrient and growth factor fraction; secondly, cells were grown in one medium, varying the level of 2, 4‐D. In cotton, the rate of metabolism of chlortoluron correlated with the extent to which the four media supported cell growth, Variations were also seen for maize but no correlation with growth rate could be made. For both species, metabolism was retarded when cells were sub‐cultured from a medium lacking coconut water to one containing 10% of this supplement. A fifty‐fold range in concentration of 2, 4‐D had little effect on metabolism in cotton, although a fall‐off in rate occurred at the highest level. However, in maize a marked trend towards accelerated metabolism with increasing content of 2, 4‐D up to 20 mg litre−1 was seen, which was independent of effects on growth.The qualitative nature of chlortoluron metabolism in both species was unperturbed by substantial variations in the composition of the medium.
Phloem translocation of non‐ionised chemicals in Ricinus communis
Authors: Bromilow Richard H. , Rigitano Renê L. O. , Briggs Geoffrey G. , Chamberlain Keith 
Published: November 2006

AbstractTechniques using R. communis were modified to enable the movement of chemicals in phloem and the factors controlling their distribution in the plant to be described quantitatively. The non‐ionised chemicals tested, aminotriazole, O‐methylcarbamoyloximes (including aldoxycarb and oxamyl) and phenylureas, spanning a range of lipophilicity of log KOW= −0.87 to +2.27, all freely entered the phloem. However, only the more polar compounds were retained sufficiently in the phloem to be transported over long distances, indicating that polar compounds cross cell membranes more slowly than compounds of intermediate lipophilicity; these findings substantiate the ‘intermediate permeability hypothesis’ of phloem translocation of xenobiotics. However, the amount of chemical reaching or retained in the sink tissues, especially in the root, was small even for the chemicals that were translocated best in the phloem.
Influence of carbaryl on nitrogenase activity and combinations of butachlor and carbofuran on nitrogen‐fixing micro‐organisms in paddy soils
Authors: Jena P. K. , Adhya T. K. , Rajaramamohan Rao V. 
Published: November 2006

AbstractThe influence of pesticides applied either singly or in combination on soil nitrogenase and nitrogen‐fixing micro‐organisms was investigated. Carbaryl, an insecticide commonly used in rice, had almost no effect on nitrogenase under submerged conditions while activity was stimulated even at 10 μg g−l under non‐flooded conditions. Application of the herbicide butachlor or the insecticide carbofuran (at 2 μg g−1) reduced the population of Azospirillum and anaerobic nitrogen fixers in a non‐flooded alluvial soil. In contrast, butachlor stimulated the population of anaerobic nitrogen fixers in an acid sulphate saline Pokkali soil under a similar water regime. Further, an increased level of carbofuran (4 μg g−1) stimulated the population of Azospirillum and anaerobic nitrogen fixers in both the soils. This stimulatory effect occurred, though not to the same extent, in the presence of butachlor which, when applied alone, inhibited the population of Azospirillum and anaerobic nitrogen fixers in alluvial soil. In Pokkali soil the combination of carbofuran and butachlor inhibited the population of Azospirillum, while carbofuran alone at 4 μg g−1 was stimulatory. These results suggest that under tropical conditions the effects of pesticides on nitrogen fixation and nitrogen‐fixing populations depend upon pesticide concentration, water regime and soil type.
Dissipation of propiconazole residues in and on wheat (Triticum aestivum L.)
Authors: Bai Qing‐Yun , Liu Chang‐Wu 
Published: November 2006

AbstractIn a 2‐year investigation, the dissipation of residues of the fungicide propiconazole from winter wheat straw and leaves was measured by periodic sampling of the green plant material from several plots that had been sprayed with ‘Tilt 2.50EC’ at three different rates.The fungicide deposits on straw and leaves at day 0 were approximately one‐quarter of the dose applied on all treatment plots, and this fraction did not differ significantly between three dosage rates.The fungicide residues disappeared rapidly, and the half‐life of the fungicide on straw and leaves was approximately 5 days. At harvest time, the fungicide residues in grain and soil were negligible, but the residues remaining on straw and leaves were considerable, especially at higher spraying rates than the recommended dosage.
Experimental design and response surface analysis of pesticide trials
Authors: Pike Derek J. , Hasted Anne M. 
Published: November 2006

AbstractThe search for combinations of pesticides or herbicides which have a synergistic effect is an important area of study and one which presents challenges for the statistician as well as for the experimenter. The aim is to find and to describe the interaction between a number of quantitative factors, and having done so to determine a combination which is economically optimal for a given level of control. The present paper discusses the role of a family of response functions called Inverse Polynomials to describe such phenomena. Examples are given of such functions and it is shown how it is possible to fit these functions to data and to plot the results on a routine basis. The importance of the experimental design for the estimation of such nonlinear regression models is investigated, and examples are given of experimental designs which are ‘optimal’ with respect to particular aims of the experimenter.
Studies on octylphenoxy surfactants. Part 1: Effects of oxyethylene content on properties of potential relevance to foliar absorption
Authors: Stevens Peter J. G. , Bukovac Martin J. 
Published: November 2006

AbstractSelected properties of octylphenol and seven of its ethoxylated derivatives were studied as a preliminary to investigating their effects on the foliar absorption of three model compounds and the surfactants themselves. Surface tension of the surfactants (2 g litre−1 in water) increased with their hydrophile:lipophile balance (HLB) which is a function of oxyethylene (EO) content. The surface tension of the aqueous surfactants was inversely related to the cosine of their contact angle (θ) on maize leaf in the EO range 7.5–30. Cos θ was in turn related to the wetting of maize by aqueous acetone solutions of surfactants with EO >9.5. The critical surface tension required for complete wetting of the adaxial surface of maize leaf was estimated to be 29 mN m−1. Evaporation of drops of aqueous acetone solutions was biphasic, with preferential loss of acetone during the initial, more rapid phase. The rate of evaporation from the remaining, effectively aqueous systems was inversely related to the HLB of the surfactants. Phytotoxicity of the surfactants, as measured by ethylene production, increased with decreasing EO, while their hygroscopic water retention increased with both log EO and relative humidity (r.h.). Aqueous solubilities of pentacosane, DDT and atrazine were increased up to 8‐fold by surfactant (20 g litre−1). Maximum solubilities were observed with surfactants having intermediate HLB values. The solubility of pentacosane (maximum 221 μg litre−1) indicated that the surfactants would probably not solubilise more than 0.1% of the epicuticular wax when applied to maize leaf. Scanning electron microscopic observation of leaf surfaces exposed to surfactants for 24 h did not reveal any visible modifications of the wax structure. Volatilisation of DDT was reduced in the presence of surfactants but that ofatrazine was increased, although in inverse proportion to its solubility in aqueous surfactant.
The absorption of cypermethrin in the grasshopper Melanoplus sanguinipes (Fab.): Effects of volatilisation, temperature, age, sex and parasitisation by Malameba locustae (King and Taylor)
Authors: Hinks Christopher F. , Westcott Neil D. , Reichle Randy A. , Spurr David T. 
Published: November 2006

AbstractThe residues from metered doses of cypermethrin were recovered from excised portions of grasshopper cuticle to determine losses by volatilisation. Residues from similar doses were also recovered from the cuticles of intact grasshoppers and from whole body homogenates after rinsing the cuticle, to determine rates of absorption and losses from metabolism. Residues were recovered from males and females one week and three weeks after fledging in grasshoppers infected with Malameba locustae and in uninfected ones. They were maintained at 15 or 30°C and sampled from each combination of factors at 4, 8, 16, 24, 30 and 48 h after treatment. There was no measurable loss of cypermethrin by volatilisation up to 72 h after application to excised portions of cuticle at either 15 or 30°C. In all combinations of factors, more cypermethrin was recovered externally (P <0.05) from grasshoppers held at 15°C than those held at 30°C and more from infected grasshoppers than from those that were uninfected. Significantly more cypermethrin was also recovered externally from males than from females (P <0.05) and more from infected one‐week‐old grasshoppers than those that were three weeks old. At 15°C there was a gradual trend towards accumulation of cypermethrin internally, but at 30°C an initial trend towards accumulation was followed by one of decline. Residual cypermethrin recovered could in general be related to the negative temperature coefficient of toxicity, to a decreased sensitivity to cypermethrin in infected grasshoppers and to an increased sensitivity in older grasshoppers.
Efficacy of current and potential grain protectant insecticides against a fenitrothion‐resistant strain of the sawtoothed grain beetle, Oryzaephilus surinamemis L
Authors: Collins Patrick J. , Wilson Debra 
Published: November 2006

AbstractThe responses of a highly fenitrothion‐resistant and a susceptible strain of Oryzaephilus surinamensis L. from Australia were measured against a range of alternative grain protectants using impregnated‐paper and treated‐grain assays.The R‐strain was also highly resistant to carbaryl, moderately resistant to malathion and pirimiphos‐methyl and showed low‐level resistance to methacrifos, chlorpyrifos‐methyl, bioresmethrin, permethrin, cyfluthrin, cypermethrin and dichlorvos. There was marginal resistance to deltamethrin. Methoprene, to which there was no resistance, was the most effective material at suppressing progeny production of the resistant strain. At current commercial application rates chlorpyrifos‐methyl was the only compound of those tested that would completely control both adults and larvae of resistant O. surinamensis for a storage period of nine months.Overall, the homogeneity of response of both strains to insecticides using the treated‐grain assay was as good as the response from impregnated‐paper assays. The latter also tended to exaggerate resistance factors compared to the treated‐grain assays.
The cuticle, growth and moulting in insects: The essential background to the action of acylurea insecticides
Authors: Reynolds Stuart E. 
Published: November 2006

AbstractThe functions, structure and biochemistry of the insect cuticle in relation to the moulting cycle are briefly reviewed as an introduction to the actions of insecticides that act on the cuticle, particularly acylureas. The symptoms of poisoning with diflubenzuron (DFB) and other acylureas are consistent with ultra‐structural and biochemical evidence that these insecticides inhibit the formation of chitin microfibrils in newly synthesised cuticle. It is probable that DFB acts at a late stage in chitin biosynthesis, perhaps inhibiting chitin synthase (CS) itself. However, the results of studies using cell‐free preparations of CS have not, on the whole, supported this hypothesis. A number of alternative suggestions as to the mode of action of DFB are reviewed. Among the most attractive of these is the possibility that DFB may inhibit the transmembrane transport of chitin synthesis precursors from their site of production within the epidermal cells to the site of the final poly condensation reaction, presumably at the apical membrane of the epidermal microvilli.
Accumulation of malathion residues in grain stored on malathion‐treated wood surfaces
Authors: Mensah G. W. K. 
Published: November 2006

AbstractLaboratory studies were conducted to determine whether insecticides applied to storage structures are able to move past a single layer of grain kernels to give adequate control of stored‐grain insects. The extent of uptake of insecticides was assessed on three layers of wheat in contact with wood surfaces treated with malathion 836 g litre−1 e.c. at 1–0 g a.i. m−2 using chemical and biological methods at predetermined time intervals. There was a progressive uptake of malathion beyond the layer directly in contact with the treated surfaces and the uptake depended on the duration of storage. After 8 weeks a sufficient amount of malathion accumulated on the top layer of grain kernels to cause 100% mortality of adult Tribolium castaneum (Herbst).
The conjugation and accumulation of metabolites of cypermethrin by earthworms
Authors: Curl Elizabeth A. , Edwards Peter J. , Elliott Clare , LeAhey John P. 
Published: November 2006

AbstractWhen earthworms are maintained in soil containing [14C]cypermethrin they accumulate radioactive residues. These residues are not eliminated when the worms are transferred to untreated soil. The accumulated radioactive residue is a complex mixture of conjugates of two metabolites of cypermethrin (3‐phenoxybenzoic acid and (1RS)‐cis, trans‐3‐(2,2‐dichlorovinyl)‐2,2‐dimethylcyclopropanecarboxylic acid). One major constituent of this mixture of conjugates has been identified as N1, N12‐di‐(3‐phenoxybenzoyl)spermine. Feeding studies with quail and rats have established that the residues accumulated by the earthworms are not further bioaccumulated by earthworm predators.
The response of three soil fungi to dalapon and diuron treatments
Authors: Tan T. K. , Chua L. H. 
Published: November 2006

AbstractDalapon and diuron are two common herbicides used for the control of weeds. A study of the response of Gliocladium virens, Trichoderma hamatum and T. koningii in cultures to the herbicides was carried out. Changes in fungal colony morphology and growth and sporulation rates in the presence of up to 105 mg herbicide litre−1 were monitored. The three fungi were not adversely affected at a concentration of 103 mg litre−1. Changes in colony morphology and decreases in growth and sporulation rates were evident at the maximum test concentration (105 mg litre−1) of both herbicides. These generally recovered when the fungi were replated in the absence of the herbicides.