bluuebunny/crossref_metadata_2025 huggingface dataset:
Preliminary studies on the insecticidal activity and wash‐fastness of twelve pyrethroid treatments impregnated into bednetting assayed against mosquitoes
Authors: Lindsay Steven W. , Ismai Hossainl M. , Bennett Stephen , Curtis Christopher F.
Published: November 2006

The insecticidal properties of twelve pyrethroid preparations impregnated into polyester netting were compared, before and after washing, with a view to assessing their suitability for treating bednets (mosquito nets) in the field. Bioassays were carried out by exposing the mosquitoes, Anopheles gambiae Giles sensu stricto andAedes aegypti L. to netting with two concentrations of insecticide, on washed and unwashed samples, for 30 s and 3 min at different times after impregnation. Mortality was recorded after 24 h. Permethrin applied at 97°C at pH 3.4 resulted in increased uptake by polyester fibres. The performance of most insecticides on unwashed netting had not declined appreciably 12 weeks after impregnation. However, all the insecticides were depleted by washing. The treatments with best insecticidal activity after washing were cypermethrin, lambda‐cyhalothrin applied at ambient temperature and normal pH and permethrin applied in a hot acid solution.
Field effectiveness and biodegradation of cyclic imides in lettuce field soils
Authors: Martin Christian , Davet Pierre , Véga Danielle , Coste Camille
Published: November 2006

When 42 field trials, carried out from 1975 to 1989 in the Perpignan region (France) for control of lettuce drop caused by Sclerotinia minor, were compared, a decrease in the field effectiveness of cyclic imides was perceptible, beginning approximately in 1985. Moreover, in 15 out of 46 commercial lettuce fields surveyed in 1988 and 1989, the effectiveness of iprodione was less than 80%, the level of acceptability for the growers. In these fields, fungicide degradation, estimated by 3,5‐dichloroaniline formation, was faster than in soils in which S. minor was adequately controlled. Statistical analyses showed that the iprodione degradation index was strongly linked to the history of fungicide treatment and was weakly correlated to soil pH or clay content. All the fields characterized by low iprodione effectiveness were associated with high levels of fungicide treatment and high degradation index. Moreover, we observed that soil from a field which had received iprodione for more than ten years did not degrade vinclozolin quickly, while soil from another part of the same field which had been treated with vinclozolin for eight years degraded vinclozolin faster than iprodione.
Automated quasi‐continuous immunoanalysis of pesticides with a flow injection system
Authors: Krämer Petra M. , Schmid Rolf D.
Published: November 2006

Chemical methods (HPLC, GC/MS) for the control of pesticides in water at low concentrations are time‐consuming, expensive and need sample pre‐concentration. Immunoassays offer the potential of rapid, inexpensive, sensitive and specific detection methods. This paper presents a flow injection system that is based on immunochemical reaction and which provides the opportunity for automated, quasi‐continuous measurements for screening water samples for the presence of pesticides.

The method of flow injection immunoanalysis (FIIA) was compared with competitive ELISA (enzyme‐linked immunosorbent assay). It is possible to measure in the range of interest of 0·1 μg litre−1, which is the limiting value of the European drinking water directive.

Measurements were made for the triazine herbicides atrazine and propazine, which both cross‐react with the polyclonal antiserum used.

Furthermore, this device includes a new development of a membrane reactor for the exchange of used biological material, in this case antibodies. A brief comparison of ELISA and FIIA is presented, giving an overview of some aspects of the assays.
Automated conformational analysis and structure generation
Authors: Leach Andrew R.
Published: November 2006

An approach for automatically and rapidly searching a molecule's conformational space to determine low‐energy conformations is described. The method takes a simple 2D description of the molecule (atom types and connectivity), recognizes the presence of conformational units about which it has ‘knowledge’ and generates structures by template joining. Some of the algorithms which can be used to search the conformational space are described, as are methods to manipulate conformational information. Such an approach may be used to generate multiple conformations which may be further refined or stored in some form of 3D database.
GABA receptors of insects susceptible and resistant to cyclodiene insecticides
Authors: Anthony Nicola M. , Benner Eric A. , Rauh James J. , Sattelle David B.
Published: November 2006

Toxicity tests revealed up to 40‐fold resistance to a number of cyclodiene insecticides in a laboratory‐reared, cyclodiene‐resistant (CYW) housefly strain (Musca domestica L.). Using [35S] TBPS as a probe for convulsant sites in insects, saturable specific binding was detected in thorax and abdomen membranes prepared from housefly strains susceptible (CSMA) and resistant (CYW) to cyclodienes. Scatchard analysis of[35S] TBPS binding data to CSMA and CYW membranes failed to provide evidence for significant differences between the two strains in either the affinity (Kd) or density (Bmax) of saturable binding sites. For several polychlorocycloalkane insecticides, the ligand displacement profile of [35S] TBPS binding was almost identical for the CSMA and CYW houseflies. Therefore, using [35S] TBPS as a probe for convulsant sites, a 40‐fold resistance to cyclodienes in the CYW housefly strain cannot be accounted for only in terms of alterations in TBPS binding sites.
Development and assessment of a mathematical model to predict foliar spray deposition under laboratory track spraying conditions
Authors: Grayson B. Terence , Webb James D. , Pack Simon E. , Edwards Dean
Published: November 2006

A mathematical model based on Young's equation of adhesion of liquids to solid surfaces has been developed to predict foliar spray deposition under track‐spraying conditions. The model incorporates the physical nature and morphological characteristics of the plant leaf surface and the physical properties of the spray solution. It was tested using experimental spray deposition measurements on four different plant species and an artificial target of glass rods with an array of forty‐eight solutions varying systematically in composition and properties. The morphological factors and regression coefficient of the model were calculated by a least‐squares multiple‐regression analysis of the observed spray deposition. The physical natures, wettabilities, of the target surfaces were estimated from contact angle measurements. The physical properties of the spray solutions, drop sizes and dynamic surface tensions were measured by a Malvern 2600 HSD particle size analyser and the maximum bubble pressure method respectively. Drop sizes were approximately constant through the series of solutions though dynamic surface tensions varied and form an important term in the model.

The spray depositions predicted by the model were plotted as response surfaces against solution composition and compared with those from the observed spray depositions. Agreements were high (explained variances, wheat, 96.4%; green foxtail, 98.6%; pea, 98.9%; sugar beet, 98.6%; glass rods, 99.4%), giving confidence that the model had been correctly formulated.

An explanation for the varying abilities of different plants to capture different volumes of spray solutions can now be expressed in qualitative and quantitative terms. Further validation of the model is in progress.
Quinone activation of protoporphyrinogen oxidase of barley plastids
Authors: Tietjen Klaus G.
Published: November 2006

Protoporphyrinogen oxidase catalyzing the oxidation of protoporphyrinogen to protoporphyrin is the target enzyme for several highly active herbicides. The plastidic plant enzyme under normal conditions uses oxygen as electron acceptor. Duroquinone, however, can be an alternative electron acceptor of protoporphyrinogen oxidase of barley plastids. In this respect the enzyme from the plastids may be an evolutionary intermediate between bacterial enzymes coupled to ubiquinone and mammalian mitochondrial enzymes coupled to oxygen.
A modified clean‐up for the determination of glyphosate and its metabolite residues in lentils using high pressure liquid chromatography and post‐column fluorogenic labelling
Authors: Wigfield Yuk Y. , Lanouette Monique
Published: November 2006

An analytical method is presented for the analysis of glyphosate and its metabolite (aminomethyl)phosphonic acid (AMPA), in lentil samples. They were extracted from powdered samples with water and chloroform. The aqueous layer was acidified and passed through a cation exchange column. The eluate was made basic, passed through an anion exchange column in the hydroxide form and discarded. The latter column was eluted with hydrochloric acid (0.3 M) which was collected, evaporated under vacuum to 1 ml, diluted with water to 10 ml, filtered and analysed for glyphosate and metabolite using a liquid chromatograph with a post‐column reactor and a fluorescence detector. The limit of detection, average recovery and coefficient of variation (CV) were 0.08 μg g−1, 92.5% and 7.3% for glyphosate and 0.1 μg g−1, 92.5% and 8.3% for AMP A. The detector response was found to be linear within the range 20–400 ng.
Off‐target glyphosate deposits from aerial silvicultural applications under various meteorological conditions
Authors: Payne Nicholas J. , Thompson Dean G.
Published: November 2006

Aerial spray applications of the herbicide glyphosate were made over a forest canopy under various meteorological conditions. A ‘Thru Valve Boom’ dispersal system carried by a Cessna 188 fixed‐wing aircraft flying at 49 m s−1 was used to generate an aqueous spray cloud with a volume median diameter of 150 μm. Glyphosate deposits from multiple overlaid crosswind line sources released at 10 m above ground level were measured on ground sheets and artificial foliage at downwind distances between 50 and 400 m. Trials were conducted in stable, neutral and unstable atmospheric boundary layers with average wind speeds between 2·2 and 5·7 m s−1 and vertical intensities of turbulence between 0·07 and 0·16. Linear regression lines fitted to logarithmically transformed measurements and downwind distances (x) gave statistically significant correlation coefficients (P = 0·01), and were compared by ANOVA. Glyphosate deposits on ground sheets and artificial foliage were attenuated at rates inversely proportional to x to the power 1·7‐4·3. Regression line comparison showed that, in general, deposits on ground sheets decreased with increasing wind speed and intensity of turbulence, and some statistically significant differences were found in slopes and elevations of regression lines from different trials. However, deposits at the 50‐m station increased with wind speed due to the large‐drop cloud component. Regression line comparison for deposits on artificial foliage showed that, in general, they were highest in the intermediate wind speed‐neutral stability case and similar in the high wind speed‐unstable and low wind speed‐stable boundary layers, although deposits at the 50‐m station also increased with wind speed.
Solid‐phase extraction and gas chromatographic determination flumethrin residues in honey
Authors: De Paoli Mauro , Barbina M. Taccheo
Published: November 2006

A gas chromatographic method to determine flumethrin (‘Bayvarol’) in honey samples is described. The method consists of solid‐phase extraction with RP C‐18 cartridges, clean‐up if required on silica cartridges, and quantitation of the active ingredient with an electron capture detector using deltamethrin as internal standard. Compared to previous methods it is very rapid, and a number of samples can be prepared simultaneously. The minimum detectable quantity is 0·005 mg kg−1 and mean recoveries are of the order of 95%.
Extraction of carbaryl from stored rice, maize, peas and sunflower seeds prior to chromatographic analysis
Authors: Brayan John G. , Haddad Paul R. , Sharp Gerald J. , Dilli Sergio , Desmarchelier James M.
Published: November 2006

Carbaryl was extracted from aged samples of rice, maize, peas and sunflower seeds using hexane, acetone and methanol. The quantities of insecticide extracted from the grain by acetone and methanol were much higher than that extracted by hexane for all four products. Methanol extracted higher levels of carbaryl than acetone from maize and peas but for rice and sunflower seeds the results were similar for the two solvents. Extraction by simply standing the whole grain in solvent for 48 h generally resulted in similar extracted levels of carbaryl to those obtained using more exhaustive techniques, such as grinding the grain or Soxhlet extraction. However, grinding or Soxhlet extraction removed the pesticide from the grain more rapidly.
Synergism of teflubenzuron and chlorfluazuron in an acylurea‐resistant field strain of Plutella xylostella L. (lepidoptera: Yponomeutidae)
Authors: Ismail Fauziah , Wright Denis J.
Published: November 2006

Topical application of the synergists piperonyl butoxide (PB) and S,S,S‐tributyl phosphorotrithioate (DEF) to second‐instar larvae of a standard laboratory strain (FS) and an unselected Malaysian field strain (CH) of the diamondback moth Plutella xylostella had no significant effect on the toxicity of the acylurea insecticides, chlorfluazuron and teflubenzuron, in a subsequent leafdip bioassay. In contrast, pre‐treatment with PB or DEF in acylurea‐selected subpopulations of the CH strain with varying levels of cross‐resistance to chlorfluazuron and teflubenzuron significantly increased (up to 34‐fold and 28‐fold, respectively) the toxicity of both compounds, suggesting that microsomal monooxygenases and esterases may be involved in resistance. The addition of a mineral oil, ‘Sunspray 6E’, to topically‐applied chlorfluazuron consistently reduced its LD50 value, and the effect of the oil appeared to be greatest on the most resistant population of P. xylostella. However, the effects of the oil were not significant (P > 0·05) and further studies are necessary to determine whether a penetration factor is present in the CH strain.
Photolysis of dimepiperate in aqueous solution
Authors: Pusino Alba , Gessa Carlo , Liu Weiping
Published: November 2006

Dimepiperate, S‐(1‐methyl‐1‐phenylethyl) piperidine‐1‐carbothioate (I) was degraded in aqueous solution by ultraviolet irradiation into piperidine (II), α‐methylstyrene (III), acetophenone (IV), and formaldehyde (V). The reaction followed first‐order kinetics. In sunlight the reaction occurred only in the presence of a sensitiser and afforded the same four photolytic degradation products. In the absence of oxygen the herbicide was converted much more rapidly, but yielded only (II) and (III) as products. A mechanism which accounts for the formation of the photoproducts is proposed.
Effect of abamectin on electrophysiological activity in the ventral nerve cord of Periplaneta americana L.: Correlation with symptoms of poisoning and levels of toxicant in vivo
Authors: Corbitt T. S. , Djamgoz M. B. A. , Wright D. J.
Published: November 2006

Twenty‐four hours after injection of adult male Periplaneta americana with 36 ng [5‐3H]abamectin, when symptoms of poisoning were apparent in most individuals, similar levels of radioactivity were found in tissue samples from the ventral nerve cord, metathoracic muscle, fat body and testis of randomly‐selected insects. When insects injected with [5‐3H]abamectin (36 ng) were separated after 24 h into three groups showing varying symptoms, the level of radioactivity in the ventral nerve cord was found to be significantly greater in partially‐paralysed and paralysed groups (4‐ and 7‐fold respectively) than in a treated but non‐ paralysed group. The mean levels of abamectin in the nerve cords of unaffected, ‘partially‐paralysed’ and ‘paralysed’ insects were estimated to be 4, 23 and 37 nM respectively. Extracellular studies of the in‐vitro action of abamectin (10 nM and 1 μM) on the spontaneous activity of a picrotoxin‐sensitive, partially desheathed, ventral nerve cord preparation of adult male P. americana found the mean response time to be relatively slow (77 and 38 min respectively). In sheathed nerve cords, the mean response time to abamectin (1 μM) was 117 min. In all cases, treatment with abamectin increased the stimulus voltage required to evoke a response. Spontaneous activity was found to be progressively reduced in ventral nerve cord preparations from ‘partially‐paralysed’ and ‘paralysed’ insects compared with ‘non‐paralysed’ and untreated insects following dissection 24 h after injection of P. americana with unlabelled or labelled abamectin (36 ng), while the stimulus required to evoke activity in the ventral nerve cord showed the reverse trend. These differences in electrophysiological activity could be correlated directly with varying levels of abamectin in the nerve cords of ‘paralysed’ and ‘partially‐paralysed’ insects.
Quantitative structure–activity studies of optically active 2‐methoxy‐1,3,2‐oxazaphospholidine 2‐sulfides against Musca domestica L
Authors: Hirashima Akinori , Eto Morifusa
Published: November 2006

The quantitative relationship between the structure of optically active 4‐substituted 2‐methoxy‐1,3,2‐oxazaphospholidine 2‐sulfides (4‐RMOS) and their insecticidal activity on the house fly, Musca domestica L., was analysed using reported physicochemical parameters and regression analysis. The configuration at the C4 atom was more important for insecticidal activity than that at the phosphorus atom, since the coefficient of the dummy parameter for the C4‐ configuration was larger than that for the configuration of the phosphorus atom: (S)c(R)p diastereoisomers showed the highest insecticidal activity, and the activity decreased in the order of (S)c(R)p > (S)c(S)p > (R)c(R)p > (R)c(S)p. The electronic nature of the substituent at the C4 position was the most important, followed by the steric and hydrophobic effects: the more electron‐donating, the less bulky and the more hydrophobic the 4‐substituent, the higher the insecticidal activity. Thus the highest activity was obtained for the isopropyl derivatives, and the activity decreased in the order of isopropyl > isobutyl > ethyl > sec‐butyl > benzyl > phenyl > methyl > tert‐butyl.
Behaviour of ddt in three soils exposed to solar radiations under different conditions
Authors: Nair Amit , Samuel Thomas , Pillai Madathil K. K.
Published: November 2006

Volatilization, mineralization, degradation and binding of soil‐applied [14C]DDT were studied in three different soils from a tropical region of southern India subjected to solar irradiation and flooding for a period of 42 days. The soil types–red cotton soil, nursery soil and canal bank soil–differed in their organic carbon content, pH and texture. Under unflooded conditions, volatile losses were highest in the sandy canal bank soil. Flooding significantly enhanced volatilization, and this effect was maximal in the nursery soil, which had the highest organic carbon. The soils fully exposed to solar radiations in quartz tubes registered 1.5‐1.8 times greater volatility. The volatilized organics contained appreciable quantities of DDE under both flooded and unflooded conditions. In addition, greater quantities of DDD volatilized from the flooded systems. The rate of formation of DDE was faster when soils were irradiated in quartz tubes. Mineralization remained minimal throughout the period of exposure and flooding the soil appeared to reduce further the [14C]carbon dioxide evolution. Canal bank soil exhibited the least mineralization and degradation. The data indicate that volatilization was significantly influenced by solar radiation and flooding to a much greater degree than by the differences in soil properties. Binding of DDT to soil was significantly increased by flooding the soil, thus leaving up to 33% of the initial DDT as bound residues in the nursery soil.
Preparation of controlled‐release formulations of 14C‐labelled thiobencarb herbicide and study of their environmental behaviour
Authors: Hussain Manzoor , Gant Jianying , Rathor M. Nasir
Published: November 2006

Controlled‐release formulations of 14C‐labelled thiobencarb herbicide were prepared in calcium alginate using kaolin as an inexpensive filler. The rates of release of the herbicide from these and from a commercial granular formulation were studied in static distilled water contained in open and closed vessels. The rate of release of the herbicide was much higher from the commercial formulation than from the controlled‐release formulations. Increasing the proportion of kaolin to calcium alginate in controlled‐release formulations reduced the rate of release of the herbicide. There was a significant loss of thiobencarb‐related radioactivity from the water solution when the vessels containing the solutions were left uncovered and exposed to light. The loss of the herbicide seemed to be due to degradation and evaporation.
Abiotic degradation pathways of isoxaben in the environment
Authors: Mamouni Abderrahim , Schmitt Philippe , Mansour Mohamed , Schiavon Michel
Published: November 2006

Photolysis of isoxaben [N‐[3‐(1‐ethyl‐1‐methylpropyl)isoxazol‐5‐yl]‐2,6‐dimethoxybenzamide] in dilute aqueous solutions, adsorbed on silica gel plates, has been investigated under natural and simulated solar light conditions. Eight photoproducts were isolated and identified by spectroscopic methods. Photo‐decomposition with sunlight led to the formation of three isomers, dimethoxy‐benzonitrile and dimethoxybenzamide as major photoproducts. The rearrangement has been shown to proceed in two photochemical steps by way of an azirine and a non‐identified photoproduct as stable intermediates. The azirine rearranges almost quantitatively to an oxazole and rearranges back to the starting isoxaben.
Structure—activity relationships in pyrethroid esters derived from substituted 2‐phenoxy‐3‐methylbutanoic acids
Authors: Nisha George , Kalyanasundaram Muthuswamy
Published: November 2006

Non‐cyclopropane pyrethroid esters of different substituted 2‐phenoxy‐3‐methylbutanoic acids have been synthesised using the three alcohols—3‐phenoxybenzyl alcohol, α‐cyano‐3‐phenoxybenzyl alcohol and 3, 4‐methylene‐dioxybenzyl alcohol. Among the 35 esters synthesised and tested against Culex quinquefasciatus Say, the Bancroftian filariasis vector, for both larvicidal and adulticidal activities, α‐cyano‐3‐phenoxybenzyl 2‐(4‐fluorophenoxy)‐3‐methylbu‐tanoate, with an LC50 value of 2.5 × 10−3 mg litre−1 for larvicidal activity, and α‐cyano‐3‐phenoxybenzyl‐2‐(4‐chlorophenoxy)‐3‐methylbutanoate, with an LD50 value of 30 times; 10−4 ug insect−1 for adulticidal activity, were found to be as effective as fenvalerate, a well‐known non‐cyclopropane pyrethroid ester. Structure‐activity studies showed that the insecticidal activity is dependent on the nature and position of the substituent in the phenyl ring of the acid moiety and also on the type of alcohol moiety.
Multivariate structure‐property relationships (MSPR) of pesticides
Authors: Domine Daniel , Devillers James , Chastrette Maurice , Karcher Walter
Published: November 2006

Vapour pressures, aqueous solubilities, n‐octanol/water partition coefficients, molecular weights, and Henry's law constants for 64 pesticides were obtained from the literature and analysed by means of Principal Component Analysis (PCA). Classical PCA displays underline structure‐property relationships. However, interpretation of PCA requires reference to the original data matrix and comparisons made between every point. To overcome this problem, a novel graphical approach, based on collections of maps encoding the chemical and structural information included in the original data set, was used to interpret the results. Multivariate analyses coupled to graphical tools were useful for interpreting physicochemical properties of pesticides in terms of multivariate structure‐property relationships (MSPR).
Inhibition of Echinochloa crus‐galli var. frumentacea seedling root elongation by chiral 1, 3, 5‐triazines in the dark
Authors: Omokawa Hiroyoshi , Konnai Makoto
Published: November 2006

2‐z‐Substituted benzylamino‐4‐substituted‐amino‐6‐chloro‐1,3, 5‐triazines are herbicidal compounds showing leaf‐burning and/or growth inhibition with concomitant greening and stunting. Effects of chiral 1,3,5‐triazine compounds in a light‐independent seedling root elongation test with Echinochloa crus‐galli var. frumentacea Wight demonstrated an interaction between chirality and root growth inhibition. The test compounds inhibited root growth, and this inhibition was due to interference with a system or systems other than photosynthesis. 4‐(R)‐sec‐butylamino‐2‐(α,α‐dimethylbenzyl)amino‐6‐chloro‐1,3, 5‐triazine showed the highest inhibitory activity, and 4‐methylamino‐2‐(R)‐a‐methylbenzylamino‐6‐chloro‐1,3,5‐triazine was second. The chiral requirement for a strong inhibition of root growth was the (R)‐configuration, contrasting with the requirement for the (S)‐configuration for an inhibition of photosystem II.
Rhizome‐induction activity of chiral 2‐α‐methylbenzylamino‐4‐alkylamino‐6‐chloro‐1, 3, 5‐triazines in Cyperus serotinus Rottb.
Authors: Omokawa Hiroyoshi , Takeuchi Masaaki , Konnai Makoto
Published: November 2006

A cytokinin‐like effect of chiral 2‐α‐methylbenzylamino‐4‐alkylamino‐6‐chloro‐1,3,5‐triazines was found using a rhizome‐inducing assay with Cyperus serotinus Rottb. tubers. C. serotinus tubers germinated in distilled water yielded plantlets with roots and leaves. Secondary rhizomes were normally not observed within the regular 14‐day incubation time in water culture, whereas after increasing incubation periods a very short rhizome appeared (controls). 6‐Benzylaminopurine (BA) significantly stimulated rhizome induction, while other plant hormones were inactive. The (R)‐isomers of the 1, 3, 5‐triazine compounds also stimulated induction of the rhizomes, whereas the (S)‐isomers did not. The described rhizome induction system seems to be suitable as a cytokinin bioassay. The (R)‐1, 3, 5‐triazine compounds showing rhizome‐inducing activity (RI activity) inhibited root formation and plant growth at high concentrations with symptoms which were very similar to those of BA. Therefore, the (R)‐isomers appear to act as cytokinins in the rhizome induction assay.
Degradation of the dicarboximide fungicides iprodione, vinclozolin and procymidone in Patumahoe clay loam soil, New Zealand
Authors: Slade E. Ann , Fullerton Robert A. , Stewart Alison , Young Harry
Published: November 2006

An enhanced rate of degradation of the dicarboximide fungicides iprodione and vinclozolin was induced in the laboratory in Patumahoe clay loam soil by adding three successive applications of fungicide. Enhanced degradation of the dicarboximide fungicide procymidone could not be induced. Following the first fungicide treatment, the time to 50% loss of iprodione was greater than 35 days; for vinclozolin the time to 50% loss was 22 days. The rate of degradation accelerated with successive applications until, after a third successive application of fungicide, the time to 50% loss of iprodione was only two days and none was detectable at seven days. For vinclozolin, after the third successive application of fungicide, 50% loss occurred after 35 days. By comparison, minimal loss of procymidone was detected after 35 days following each of two successive soil treatments.

The induction of enhanced degradation of iprodione and vinclozolin in this soil in the laboratory may explain the observed loss of field control of onion white rot disease. Degradation of iprodione occurred in non‐sterile soil but not in sterile soil, indicating that microbial involvement may be responsible for the degradation of iprodione and vinclozolin in soil.
Insecticide resistance in cotton aphid Aphis gossypii (Glov.) in the Sudan Gezira
Authors: Gubran El Mahi E. , Delorme Robert , Augé Dnielle , Moreau Jean P.
Published: November 2006

The resistance to insecticides of three Sudanese strains of A. gossypii (Glov.) collected from cotton fields in the Sudan Gezira Scheme over three seasons (1988, 1989, 1990) and that of two French strains was studied in the laboratory. When compared with a known susceptible strain, the aphids were found to be resistant‐to the eight insecticides tested. Evolution of resistance in Sudanese strains during the three crop seasons was observed. Assay of aphid homogcnate for carboxytesterase activity towards the substrates α‐naphthyl acetate and β‐naphthyl acetate showed that there was no enhancement of this class of enzyme and thus it was not a cause of resistance in this species. A study of interaction between the acetylcholinesterase (AchE) and pirimicarb established the kinetics of the inhibition process. I50 values were found to be much higher for the Sudanese strains than for the susceptible strain. First‐order inhibition kinetics revealed that resistance towards pirimicarb in Sudanese‐strains was caused by a modified AchE which had a reduced affinity (higher Ka value) and poor carbamylation ability (lower K2 value) for pirimicarb. The resistance mechanisms for the other insecticides remain to be studied.
Influence of temperature, soil moisture and soil characteristics on the persistence of alachlor
Authors: Walker Aiian , Moon Young‐Hee , Welch Sarah J.
Published: November 2006

Alachlor degradation in soils followed first‐order reaction kinetics. Half‐lives in moist soil varied from 11.30 to 34.8 days at 25°C to 95.9 to 279.6 days at 5°C, and at 15°C varied from 15.7 to 83.1 days at 5 kPa soil water stress (field capacity) to 82.8 to 281.4 days at 1500 kPa (permanent wilting point). Degradation rates in laboratory incubations with fluctuating temperatures were predicted with reasonable accuracy from the constant‐temperature data. The degradation rate and extent of adsorption were lower in subsoils than in soils from the plough layer. Degradation rate was positively correlated with microbial biomass and microbial respiration, and adsorption was positively correlated with soil organic matter content. Persistence of alachtor in field plots was correlated well with variations in weather pattern during the period September 1990 to July 1991, with an effective half‐life varying from 20 to 60 days. Persistence in the field plots was predicted accurately by a computer model of herbicide behaviour.
Fate of the benzoylphenyl urea CGA‐184699 in the cat flea Ctenocephalides felis
Authors: Zakson Michelle , Hink W. Fred , MacKichan Janis J.
Published: November 2006

HPLC was used to determine levels of the benzoylphenyl urea, CGA‐184699, in cat blood, flea faeces and eggs. Rate constants were determined for the decline of CGA‐184699 concentration in flea faeces of fleas that fed on both high (696 ng ml−1) and low (305 ng ml−1) host blood concentrations. There were strong correlations between the concentration of the drug in the host's blood and in flea eggs, between egg concentration and egg hatch and between the concentration of CGA‐184699 in faeces and mortality to larvae feeding upon faeces.
Phagodeterrent response of the bulb mite Rhizoglyphus robini to various pyrethroids and some of their cleavage products
Authors: Cohen Ephraim , Joseph Tamar
Published: November 2006

Feeding‐avoidance response of the bulb mite Rhizoglyphus robini to various insecticidal and acaricidal pyrethroids and some of their cleavage products was examined using a two‐choice cellulose disc bioassay. The mites were able to detect extremely low quantities of certain pyrethroids, down to 1–5ng of pesticide applied to a cellulose disc weighing 200 mg. The phagodeterrent potency of the pyrethroids was found to be in the following decreasing order: fenvalerate > cypermethrin > deltamethrin > bioresmetnrin > pyrethrin > bifenthrin > cis‐permethrin > trans‐permethrin. Fenpropathrin, bioallethrin, flucythrinate and tetramethrin were stimulatory up to a level of 50 ng disc−1. A 100‐ng dose of fenpropathrin deterred the mites. Chemical and photochemical cleavage products of pyrethroids possessed phagodeterrent potencies comparable to those of the intact pesticides. 3‐Phenoxybenzotc acid and cis‐chrysanthemic acid were the most effective deterrents followed by dibromochrysanthemic acid and the cis and trans bifenthrin acid moiety. The probable relevance of the observed phagodeterrence by pyrethroid residues and their cleavage products, as related to induction of dispersal and eventual outbreaks of mites, is discussed.
Synthesis and bioactivity of some fluorine‐containing benzoyl arylureas. Part I: Insecticidal‐acaricidal products in which the aryl group bears a trifluoromethyl‐substituted alkyl or alkenyl side chain
Authors: Meazza Giovanni , Rama Franco , Bettarini Franco , Piccardi Paolo , Massardo Pietro , Caprioli Vincenzo
Published: November 2006

This paper reports the synthesis and the biological activity of benzoyl arylureas in which the aryl group bears a trifluoromethyl‐substitiited alkyl or alkenyl side chain, R. The activity of these compounds has been evaluated on larvae of S. littoralis, A. aegypti, L. decemlineata and on the eggs of T. urticae. In general: (1) the optimum insecticidal activities are achieved when the substituents on the benzoyl moiety, R1, and R2, are 2,6‐difluoro, the substituents on the aryl moiety, R3, are 3,5‐dichloro and R1, is 4‐(CHC(CI)CF3); (2) the best acaricidal activity is shown when R1, is 2‐CI, R2, and R3, are hydrogen atoms and R1, is 4‐(CH2CH2CH(CI)CF3); (3) the best overall activity is displayed when R1, is 2‐CI, R2 is hydrogen, R3 is 3‐chloro and R1 is 4‐(CH2CH2CF3).
Effects of oxadixyl treatment on the ultrastructure of Phytophthora infestans infecting tomato leaves
Authors: Jiang Yong
Published: November 2006

Oxadixyl is a systemic fungicide controlling diseases caused by Oomycetes. In this ultrastructural study of the mode of action, it was found that more than 40% of 60 observed haustoria of Phytophthora infestans were less than I am in diameter in tomato leaf inner spongy mesophyll tissues previously treated with the fungicide (8 μg ml‐1) and were on average smaller than in untreated tissues. Ultrastructural observations on treated tissues also revealed that dictyosome vesicles were fewer near dictyosomes in the region of the intercellular hyphae which subtended the haustorium and in haustoria, during haustorium development. Fungal nucleoli degenerated and. in contrast to previous observations of the fungitoxic effects, numbers of ribosomes decreased in the cytoplasm, indicating that synthesis of ribosomes was probably inhibited. In addition, fragmentation of the endoplasmic reticulum and increases in the number and size of vacuoles and lomasomes were also observed in treated tissues. These results were considered to be fungistatic effects of the fungicide on the fungus. In some infected plant cells, electron‐dense deposits appeared in the cytosol in the vicinity of the extrahaustorial membrane. Compared with the nature of the related compound, metalaxyl, there appear to be differences between their effects in some aspects, e.g. haustorium development and haustorial encasement formation.
Evaluation of volatile allyl alcohol derivatives for control of snails on cut roses for export
Authors: Ittah Yitzhak , Zisman Uzi
Published: November 2006

Allyl alcohol esters (propionate, formate, and acetate) and structurally related compounds (3‐methylallyl alcohol and vinyl acetate) were evaluated for their fumigation properties vis‐a‐vis Theba pisana (Mueller) snails.

The esters were very effective in exterminating the snails, although less so than the parent alcohol. These results suggest that the esters might first have to undergo hydrolysis, and only thereafter demonstrate their potency. 3‐Methylallyl alcohol (four‐carbon member) and vinyl acetate (two‐carbon member, after hydrolysis) were significantly less potent than the allyl esters. All three esters showed less phytotoxicity towards roses than did allyl alcohol itself. However, only allyl acetate caused no damage whatsoever to the entire plant tested (flower, leaves, sepals, and stem).
Disposition kinetics, cytotoxicity and residues of fenvalerate in tissues following oral administration to goats
Authors: Mandal Tapan K. , Bhattacharya Anjan , Chakraborty Animesh K. , Basak Dipak K.
Published: November 2006

Disposition kinetics in goats of fenvalerate [(RS)‐α‐cyano‐3‐phenoxybenzyl (RS)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate] were studied after oral administration at 5 mg kg−1. The insecticide persisted in blood for up to 48 h. The Vd(area), t1/2(β), and t1/2(Ka), of fenvalerate were 12.14 (±0.39) litre kg−1, 12.25 (±0.25) h and 0.63 (±0.11)h, while the AUC and ClB values were respectively 7.35 (±0.39) μg h ml−1 and 0.68 (±0.04) litre kg−1 h−1. The residues in tissues reached a peak four days after insecticide administration and then started to decline. Maximum residue was found in the adrenal gland, followed by liver, kidney and intestine. Both GOT and GPT activities in kidney tissue, but only GPT activities in liver tissue had decreased significantly 4, 8 and 22 days post‐administration. The fenvalerate did not produce any significant effects on serum acetylcholinesterase, cholesterol or protein levels in goats. Histopathological examination showed fatty changes in the periphery of lobule, congestion in sinusoid, haemolysis in central vein, necrosis and periportal fibrosis around the central vein of liver, and necrosis in kidney of fenvalerate‐treated goats.
Selection, inheritance and characterization of carbofuran resistance in the Colorado potato beetle (Coleoptera: Chrysomelidae)
Authors: Ioannidis Philippos M. , Grafius Edward J. , Wierenga Joel M. , Whalon Mark E. , Hollingworth Robert M.
Published: November 2006

The objectives were to select for resistance to carbofuran in a susceptible field population of Colorado potato beetles, Leptinotarsa decemlineata (Say), assess the progression of resistance, and characterize the inheritance and possible mechanism of resistance. Initial selection in the field resulted in over 99.9% mortality of treated larvae but high resistance in the survivors. Subsequent laboratory selection at c.80% mortality increased resistance to > 100‐fold by the fourth generation. Low level cross‐resistance to azinphos‐methyl was also present. Resistance appeared to be inherited via a single, autosomal, incompletely dominant gene, resulting in decreased acetylcholinesterase sensitivity. A second Michigan population also appeared to exhibit reduced cholinesterase sensitivity. Resistance to carbofuran in a Colorado potato beetle population from Long Island, NY appears to involve primarily mixed‐function oxidase enzymes. The history of insecticide use probably affects which primary resistance mechanism appears in response to carbofuran treatment.
Negative cross‐resistance to N‐phenylanilines in benzimidazole‐ resistant strains of Botrytis cinerea, Venturia nashicola and Venturia inaequalis
Authors: Josepovits Gyula , Gasztonyi Maya , Mikite Gyula
Published: November 2006

A new series of compounds with high contra‐selective activity against benomyl‐resistant fungal strains was found among ring‐substituted N‐phenyl‐anilines. Hydrophobic substitution in one of the benzene rings, together with the secondary amine character of the molecule, are important factors for high fungitoxicity. The sensitivities of benomyl‐resistant isolates to some representatives of the N‐phenylanilines equal or even surpass their sensitivity to diethofencarb or MDPC. The negative cross‐resistance with benzimdazole fungicides is valid for strains of Botrytis cinerea, Venturia nashicola and Venturia inaequalis. The strains of B. cinerea with double insensitivity to benzimidazoles and phenyl‐carbamates are insensitive also to N‐phenylanilines. However, the similarly double‐insensitive strain of V. nashicola was found to be just as sensitive to the N‐phenylanilines tested as the strain resistant only to benzimidazoles. The latter result revealed an important bonus compared with diethofencarb. Preventive application of one of the most active representatives of the N‐phenylanilines to young cucumber plants was effective against infection with benomyl‐resistant isolates of B. cinerea. Moderate apical translocation after root‐dipping was also observed.
Larval feeding and movement in two Plutella xylostella (Lepidoptera: Plutellidae) populations exposed to discrete deposits of permethrin
Authors: Adams Andrew J. , Hoy Casey W. , Hall Franklin R. , Nettleton Sara Y.
Published: November 2006

Feeding and movement by two Ohio populations of diamondback moth (Plutella xylostella L.) on leaf discs treated with individually applied, uniformly‐sized droplets of permethrin was video‐recorded. Incorporation of fluorescent dye in the permethrin solution allowed comparison of the proportion of leaf area eaten with proportion of deposits consumed and measurement of distance travelled across the leaf surface between contacts with droplets. There was a direct relationship between proportion of leaf area eaten and proportion of deposits consumed (slope ∼ 1.0). Feeding by the more physiologically susceptible population was unaffected by drop size (100–220 μm, 50 drops disc−1 in each case) and the proportion of the leaf disc consumed was much less than that recorded for the more resistant population at the two smaller drop sizes (100 μm and 150 μm). These data indicate that the P. xylostella larvae showed no behavioural avoidance of deposits when feeding, but ingestion of permethrin inhibited feeding in the more susceptible population. Two equivalent measures of avoidance when moving, the average distance travelled between contacts with droplets and the average number of contacts per unit distance travelled, were not different for the two populations, indicating no difference in the average ability of insects from these populations to avoid deposits of permethrin. The average distance travelled and the average number of contacts with droplets during the 90‐min period was significantly greater for the more susceptible population, indicating that the behaviour of the two populations differed. These differences are consistent with a post‐contact irritation in the more physiologically susceptible larvae.
Kinetic and thermodynaimic aspects of the dye‐sensitised photo‐oxidation of bioresmethrin and related compounds
Authors: Clements Paul , Wells Clifford H. J.
Published: November 2006

The Rose Bengal sensitised photo‐oxidation of bioresmethrin (I), 2‐benzylfuran‐4‐ylmethyl acetate (II), and 2‐benzylfuran‐4‐ylmethanol (III) has been studied in methanol and methanol + water (1 + 1 by volume) solutions by monitoring the rate or oxygen removal from the system. The results indicate that the compounds studied are oxidised via reaction with singlet oxygen. Values for the rate constants for reaction of singlet oxygen with compounds I‐III have been determined over the temperature range 293–308 K, and the energy of activation and entropy of activation for the reactions have been determined. The data have been interpreted in terms of the site of attack of singlet oxygen on the compounds.
‘Pharmacokinetic’ and ‘pharmacodynamic’ design of lipophilic drugs based on a structural model for drug interactions with biological membranes
Authors: Herbette Leo G.
Published: November 2006

The pharmacokinetic profile a drug exhibits will ultimately depend on how the drug molecule interacts with the different cell membranes it encounters en route to its target site of action. Even if the drug molecule targets a soluble protein as its final site of action, there is a reasonable probability that it will interact with some cell membrane on its pathway to this biological target. In some cases, the final protein, lipid or sugar moiety target could be an integral part of the cell membrane architecture whereby the drug's interaction with the cell membrane could influence its pharmacodynamic profile as well, especially if the final site of action is an integral membrane‐bound receptor protein. In either case, drug transport across a cell membrane or within the cell membrane lipid bilayer compartment can dictate partial or dominant control of the drug's bioavailability. A molecular understanding of the equilibrium membrane partition coefficient, the rates of drug partitioning into and out of a cell membrane and the equilibrium location of the drug within the cell membrane can provide critical chemical design strategies for altering overall drug bioavailability and optimal pharmacokinetics.
Microcalorimetry and the Taylor—Aris method in the study of partition processes
Authors: Beezer Anthony E. , Mitchell John C. , Andrews David J.
Published: November 2006

Microcalorimetry is introduced briefly and shown to permit the development of biologically based Structure Activity Relationships (SARs). These data can be related to the more conventionally used parameter, the partition coefficient. Further, calorimetric studies are shown to allow comparison of the partitioning properties of biological cells with solvents that are normally used in drug partitioning studies. The results indicate that more consideration should be given to partitioning into particulate, e.g. micellar and liposomal, solvent systems. The use of the Taylor‐Aris dispersion broadening method is briefly introduced theoretically, and its practical exploitation is discussed.

These two techniques, microcalorimetry and the Taylor‐Aris method are shown to allow new insights into partitioning systems and their application to biological SARs.
Validation of the AGDISP Aerial Spray Deposition Prediction Model
Authors: Duan Baozhong , Yendol William G. , Mierzejewski Karl , Reardon Richard
Published: November 2006

Experimental evaluation of the computerized aerial spray prediction program (AGDISP) was conducted. Spray was applied over a flat site with a fixed‐wing aircraft. Spray droplets were collected on flat cards 15 cm above the ground. Aircraft parameters were recorded during the trials. Deposits were analyzed with image analysis equipment to establish droplet‐size spectra. A set of statistical parameters was applied to the measured and model‐predicted droplet deposition. The results indicate that the model can predict the average droplet density and volume deposition over seven spray runs within a factor of two of actual measurements.
Role of Cytochrome P450 in Tulip Bulb Probed by Substrate‐Binding Studies
Authors: Kelly Steven L. , Topal Aysegul , Barnett Ian , Kelly Diane E. , Hendry George A. F.
Published: November 2006

Microsomal fractions from dormant and wounded (sliced, aged) tulip bulbs showed a Soret peak at 448 nm in the carbon monoxide difference spectrum of dithionite‐treated membranes characteristic of cytochrome P450. Wounding and ageing induced a seven‐fold increase in P450 content. The enzyme‐substrate binding spectra and substrate affinity constants found under different conditions implied different forms of cytochrome P450. Of the several xenobiotics examined, two of them, benzo[a]pyrene and the herbicide 2,4‐dichlorophenoxyacetic acid, were inferred to be substrates from the production of P450 substrate‐binding spectra and varied substrate affinity constants were observed using the different microsomal preparations. In the wounded tissue, geraniol binding was also observed, which may reflect the endogenous function of the P450, possibly as part of a defence mechanism.