bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane partitioning of organophosphorus and organochlorine insecticides and its implications for mechanisms of toxicity
Authors: Antunes‐Madeira Maria Do Carmo , Madeira Vitor M. C. 
Published: November 2006

AbstractPartition coefficients of organophosphorus and organochlorine insecticides were determined in several types of membrane. Insecticide partitioning varied among the membranes under study, depending on temperature, cholesterol content and on the physico‐chemical profiles of membrane components and the insecticides themselves. The maximal partitions for DDT, lindane, parathion and malathion in egg phosphatidylcholine bilayers over the temperature range from 10 to 37°C (at which the lipid is in the liquid‐crystalline state) were about 260000, 2000, 1000 and 120, respectively. Incorporation of 50 mol% cholesterol in egg phosphatidylcholine bilayers dramatically decreased the partition and almost abolished the temperature effect. First‐order phase transitions of dimyristoyl‐, dipalmitoyl‐ and distearoylphosphatidylcholines (DMPC, DPPC and DSPC) were accompanied by a sharp increase in insecticide partition. Furthermore, the insecticides under study were more easily accommodated in bilayers of short‐aliphatic‐chain lipids, since higher values of partition were obtained in DMPC bilayers. Partition values in native membranes depended considerably on the membrane type and composition and were higher in sarcoplasmic reticulum (SR) and mitochondria than in brain microsomes, myelin and erythrocytes. Identical results were obtained in related liposomes of total extracted lipids, although the absolute partitions showed decreased values. In general, the incorporation of insecticides correlated reasonably with the cholesterol content of the membranes. The order of partitioning of the above insecticides did not run parallel with their toxicity to mammals and, both in model and in native membranes, followed the sequence: DDT ≫ lindane > parathion > malathion.
Biological effects and metabolism of fenoxycarb after treatment of the fourth and the fifth instars of the tobacco budworm, Heliothis virescens F.
Authors: Mauchamp Bernard , Malosse Christian , Saroglia Patrick 
Published: November 2006

AbstractTreatment of 4th and 5th instar larvae of Heliothis virescens with different amounts of fenoxycarb induced an increase in weight of the 5th larval instar, prolongation of the 5th larval instar period, or the formation of dauer larvae. No effects were observed during the 4th instar and the moult to the 5th larval instar. To check whether these effects were due to persistence of fenoxycarb in treated larvae, metabolism of this chemical was analysed. Larvae were fed with radio‐labelled fenoxycarb at the first day of the 4th or at the first day of the 5th larval instar. Behaviour of the radio‐labelled compounds was followed during each instar. At the time of gut purge, the whole of the radio‐labelled material was excreted. The effects observed during the 5th instar of 4th‐instar‐treated larvae do not appear to be due to the persistence of fenoxycarb.The main metabolites of fenoxycarb were identified using coupled gas chromatography and mass spectrometry.
Current insecticide management practices in cotton around the world–short‐term successes or templates for the future?
Authors: Sawicki Roman M. 
Published: November 2006

AbstractNationwide Insecticide Resistance Management (IRM) strategies against cotton pests in Zimbabwe, Egypt and Australia to delay build‐up of resistance to insecticides, especially the synthetic pyrethroids (SPs), are critically reviewed. It is concluded that there is a very urgent need to identify key determinants of selection for resistance by both laboratory simulation and field tests to improve knowledge of operational tactics. More reliable and rapid assays to detect resistance and a better understanding of the population dynamics of cotton pests are also needed to assess and predict rapidly and accurately the response of pest populations to countermeasures. Without such research, existing IRM strategies will remain essentially akin to models of population genetics in which scientific input has been replaced by common sense and intuition.
Pyrethroid resistance in Heliothis virescens: Current US management programs
Authors: Riley Steven L. 
Published: November 2006

AbstractThe increasing costs of insect control technology and crop production make it imperative that we clearly understand and attempt to manage insecticide resistance. The cost‐effectiveness of the synthetic pyrethroids for controlling Heliothis spp. and recent reports of resistance in major cotton producing regions around the world underscore this situation. Since 1983, a number of government, university and industry‐based programs have been initiated to monitor the spread of pyrethroid resistance in Heliothis spp. and to manage the use of the pyrethroids. In the US, four major efforts were conducted during 1987 and 1988. These were: (1) a Texas state‐wide management program, (2) a tri‐state management program in the mid‐south, (3) an adult monitoring program conducted by university personnel throughout the cotton belt and (4) an inter‐company monitoring program conducted by PEG‐US. These programs will be reviewed along with recommendations for refining future monitoring and management efforts.
Study of the disappearance of endosulfan, parathion, trichlorfon and pirimicarb from broccoli and portuguese cabbage
Authors: Magalhães Maria João A. , Ferreira Júlia R. , Frutuoso Lúcia , Taínha António A. 
Published: November 2006

AbstractThe influence of surface of exposure of brassicas to insecticide sprays has been assessed in two experiments conducted in small plots where endosulfan, parathion, trichlorfon and pirimicarb were applied to a flowering brassica, broccoli (Brassica oleracea L. var italica Plenck) and to a leafy brassica (Brassica oleracea L. var. tronchuda Bailey).The differences of surface exposure resulted in much higher deposits and subsequent residue levels in broccoli. The results stress the need to evaluate residue data on groups of brassicas of different surfaces of exposure to pesticide spray when granting registration petitions for brassicas in general in order to establish pre‐harvest intervals.
Potential for exploiting plant genes to genetically engineer insect resistance, exemplified by the cowpea trypsin inhibitor gene
Authors: Hilder Vaughan A. , Gatehouse Angharad M. R. , Boulter Donald 
Published: November 2006

AbstractOver the 400 million or so years of their co‐evolution, plants have evolved some highly effective strategies to combat herbivorous insects. Amongst these natural defence mechanisms are some which depend on a primary gene product for effect. These are currently suitable for producing insect‐resistant, transgenic crop plants by genetic engineering. One such mechanism involves the protease inhibitors from cowpea (Vigna unguiculata), which are anti‐metabolic to a wide range of insects. Cowpea trypsin inhibitor (CpTI) genes have been cloned and transferred to tobacco plants. Those transgenic tobacco plants which express physiological levels of CpTI have enhanced resistance to a wide range of insect pests. The insecticidal characteristics of these plants compare favourably with those of transgenic plants expressing the B. thuringiensis endotoxin gene. Some possible advantages of, and prospects for, using plant‐derived ‘insect‐resistance’ genes in this way are discussed.
The use of entomogenous fungi for pest control and the role of toxins in pathogenesis
Authors: Gillespie Adrian T. , Claydon Norman 
Published: November 2006

AbstractFungi have been suggested as agents for the biological control of insects for over a century, but their use remains extremely limited. This paper examines the biology of entomogenous fungi, highlighting their need for moisture, and reviews studies on the Entomophthoraceae, Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae and Verticillium lecanii. It is suggested that current studies should be directed towards the control of pests living in humid micro‐climates and that moisture‐retaining formulations should be developed to reduce the reliance of fungi on moisture.Many entomogenous fungi produce insecticidal toxins in submerged culture and these compounds are of interest as a source of new toxophores. The most extensively studied toxins are the cyclic depsipeptides from M. anisopliae, termed destruxins, and their possible role in pathogenesis is discussed. Beauveria bassiana also produces the cyclic peptides termed beauvericin, beauverolides, and bassianolide. Toxins produced by V. lecanii, and the Entomophthoraceae are also described.
Multivariate quantitative structure‐activity relationship (QSAR) methods which may be applied to pesticide research
Authors: Livingstone D. J. 
Published: November 2006

AbstractRegression analysis is the most commonly used technique in QSAR studies. Whilst regression has its advantages, it also suffers from a number of disadvantages. A variety of mathematical and statistical techniques exist which complement or replace regression. These may he classified as ‘supervised’ and ‘unsupervised’ learning methods where supervision refers to the use made of biological data in the analysis. These terms are discussed and examples of three unsupervised and two supervised learning methods are presented. The techniques described are Non‐Linear Mapping, Principal Components Analysis, Cluster Analysis, Canonical Correlation Analysis and Factor Analysis. Although the examples presented are mostly pharmaceutical applications, it is proposed that the extra complexity of pesticide research data, compared with pharmaceutical, makes it very well suited to analysis by these methods.
The pyrethroids: Early discovery, recent advances and the future
Authors: Elliott Michael 
Published: November 2006

AbstractA brief survey is given of the historical development of some of the more stable synthetic pyrethroids from the starting point of the natural pyrethrins. The main physico‐chemical, biological and toxicological properties of the synthetic pyrethroids are outlined as a background for the following papers. The importance of the pyrethroids in modern agricultural practice is stressed and areas of future application and development are discussed.
A review of the use of synthetic pyrethroids in public health and vector pest control
Authors: Carter S. W. 
Published: November 2006

AbstractThe last 40 years has seen significant evolution of the synthetic pyrethroids from their relatively restricted usage in domestic fly and mosquito control to their adoption in all major areas of public health pest control. The use of the synthetic pyrethroids in national and international control campaigns and in village level self‐help pest‐control schemes for major disease vectors such as mosquitoes, tsetse and blackfly is examined. Their successful introduction into the urban public health sector for control of cockroaches, fleas, bedbugs and lice, etc., is reviewed.
A brief review of the environmental fate and metabolism of pyrethroids
Authors: Demoute Jean‐Pierre 
Published: November 2006

AbstractPyrethroids are a class of lipophilic insecticide very easily degraded in the natural environment. The two main routes of degradation, photo‐ and biodegradation, are often superimposed. Pyrethroids developed for use in agriculture are much more photostable than the natural pyrethrins or early synthetic derivatives but they are still sensitive to sunlight, which triggers many alterations such as isomerisation or ester cleavage. The basic pathways of pyrethroid metabolism include hydrolysis of the central ester linkage and oxidation of both acid and alcohol moieties. The rate of these metabolic transformations and the nature of the metabolites depend mainly on the organism involved. Birds and mammals metabolise and excrete more rapidly than insects and fishes. In plants, initial metabolic processes are identical to those known in animals. In soil, pyrethroids undergo the same type of transformation, hydrolysis and oxidation. Neither degradation products nor intact parent compounds are leached.
Fungicidal activity of some alkylthio‐substituted 2‐iodo‐and 2‐methylbenzanilides
Authors: Carmellino Marialuisa , Massolini Gabriella , Pregnolato Massimo , Pagani Giuseppe 
Published: November 2006

AbstractSome 3′‐ or 4′‐alkylthio‐2‐iodobenzanilides and some 3′‐alkylthio‐2‐methylbenzanilides were tested in vitro and in vivo against fungal plant pathogens of different taxonomic classes and some showed activity, especially in vivo. Among all the tested compounds the 3′‐alkylthio‐2‐iodobenzanilides revealed the highest activities.
The pyrethrins and related compounds. Part XXXVII. synthesis and insecticidal properties of new 1‐aryl‐1‐(3‐arylpropyl and ‐propenyl)cyclopropanes (non‐ester pyrethroids)
Authors: Farnham Andrew W. , Ifill Anderson , Janes Norman F. , Javed Tariq , Khambay Bhupinder P. S. 
Published: November 2006

AbstractNew routes to the title compounds, involving improved conditions for the cyclopropanation, and a new method of constructing the central three‐carbon unit (based on the coupling of a Grignard reagent with an allylic acetate) give access to products for which the previously reported route was not satisfactory. For the new route, a synthesis of 5‐bromo‐2‐fluoro‐diphenyl ether was developed. Previously deduced relationships between structure and insecticidal activity apply for the new compounds: alkenes are generally more active than corresponding alkanes; substitution at the 3‐ or 4‐position (but not the 2‐) of the 1‐aryl group can enhance activity. In addition, some fluorine‐containing substituents lead to high activity.
Designing, implementing and servicing an insecticide resistance management strategy
Authors: Forrester Neil W. 
Published: November 2006

AbstractDrawing on the experience gained in the management of resistance in Heliothis armigera in Australia, the successive stages of designing, setting up and monitoring an insecticide resistance management (I R M) programme are discussed, along with the problems that may have to be overcome in order to achieve success. While individual strategies will inevitably differ, the Australian experience should give valuable information for the setting up of IRM programmes worldwide.
Determination of tau‐fluvalinate residues in honey
Authors: Barbina Maria Taccheo , De Paoli Mauro , Valentino Alan 
Published: November 2006

AbstractA capillary column gas chromatographic method is described for the determination of tau‐fluvalinate in honey samples. The method involves solid phase extraction of the sample with two RP C‐8 cartridges in series, purification of the extract, if necessary, on a silica cartridge, and detection of the active ingredient with an electron capture detector. The method is rapid and overcomes the problem of emulsion formation in liquid/liquid partition often found in traditional systems. The detection limit in actual samples is 0.01 mg kg−1 and mean recoveries for fortified samples prepared with or without clean‐up are greater than 85%.
Relation between volatility rating and composition of phenoxy herbicide ester formulations
Authors: Noble Alan , Hamilton Denis J. 
Published: November 2006

AbstractA CIPAC/AOAC test with tomato plants is used to specify the volatility ratings of herbicide ester formulations. This work compares the tomato plant test with an alternative chemical one. The concentrations of esters and the effective molecular weight and density of each formulation were used with the ester vapour pressures to calculate its herbicide vapour pressure as complete, and evaporated formulations. The range was from 28.8 mPa (at 257deg;C) for a mixture of 2,4–D esters to 0–07 mPa (at 25°C) for a 2,4,5–T‐(iso‐octyl) formulation, as complete formulations, and 35‐5 and 0–16 mPa (at 25°C) as evaporated ones. A value of 0–6 mPa (at 25°C) was selected on the basis of the tomato plant test as the cut‐off area for low‐volatile esters and is recommended to be included in specifications for herbicide esters. Formulations with a herbicide vapour pressure above 3.3 mPa (at 25°C) are high‐volatile ones according to the tomato plant test, while between 0–6–3.3 mPa (at 25°C) is a borderline region where the test gives mixed results. Levels of 2,4–D‐ethyl and methyl were added to pure 2–ethylhexyl esters of 2,4–D and a 2,4,5–T‐(iso‐octyl) formulation to find what level of contamination would change the rating of these esters from low to high volatile. Formulations of 2,4–D‐(iso‐octyl) should not contain more than 11 g litre−1 2,4–D as methyl ester or 2.0 g litre−1 2,4–D as ethyl ester. Formulations of 2,4,5–T‐(iso‐octyl) should not contain more than 26 g litre−1 2,4–D as methyl ester or 4.7g litre−1 2,4–D as ethyl ester.
The effect of selected uv absorber compounds on the photodegradation of pyrethroid insecticides applied to cotton fabric screens
Authors: Hussain Manzoor , Perschke H. , Kutscher R. 
Published: November 2006

AbstractUV absorber compounds were tested to reduce the photolytic decomposition of deltamethrin, applied to 100 % cotton fabric, to be used as a target screen for tsetse fly control. In the absence of UV absorbers, over 90% of deltamethrin was degraded after 6 h irradiation under an Osram UV‐sun radiation lamp (equivalent to 96 h sunlight) at 35(±1)°C. The degree of protection increased with increase in the proportion of the U V absorber compound. With a mixture of 2,4‐dihydroxybenzophenone (I) and deltamethrin (3 + 1, by mass) 7% of deltamethrin was degraded. Similarly, I protected alpha‐cypermethrin and cyfluthrin against photolysis, I and 2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid (IV) both protected deltamethrin from “Glossinex 200” SC formulation against photolysis, but I was more effective than IV.
Mode of action of insecticidal dihydropyrazoles: Selective block of impulse generation in sensory nerves
Authors: Salgado Vincent L. 
Published: November 2006

AbstractWhen injected into cockroaches (Periplaneta americana), dihydropyrazoles (pyrazolines), e.g. RH 3421, methyl 1‐(N‐(α,α,α‐trifluoro‐p‐tolyl)carbamoyl‐3‐(4‐chlorophenyl)‐4‐methyl‐2‐pyrazolin‐4‐ylcarboxylate, caused incoordination, followed by prostration and violent tremors. After several hours, prostrate cockroaches became very still, appearing paralyzed, but for several days they retained the ability to produce violent tremors when physically disturbed. The paralysis was associated with block of spontaneous activity in sensory nerves of cockroaches, tobacco hornworm larvae (Manduca sexta) and housefly larvae (Musca domestica). Block of spontaneous central nervous system activity was also seen in some cases.Current‐clamp experiments on the cell body of the crayfish slowly‐adapting stretch receptor neuron revealed that spike initiation in response to injected current was blocked by dihydropyrazoles, with no change in resting potential or input resistance, suggesting that the sodium current was suppressed. Hyperpolarization of blocked stretch receptors could reverse block, and crayfish giant axons, which were not normally sensitive to block by dihydropyrazoles, were rendered sensitive when artificially depolarized by elevation of extracellular potassium ion concentration, leading to the conclusion that the block of sodium current was strongly voltage dependent. The proposed mode of action, while similar to that of local anesthetics, class I anticonvulsants and class I antiarrhythmics, is novel for an insecticide.
A new fungicide—HDE and its application in controlling wilt disease of cucurbits
Authors: Li Zhichang , Liu Chiqing 
Published: November 2006

AbstractHomodemycine (HDE) is a copper complex of several different amino acids. It is a highly effective, low‐toxic and non‐residual fungicide. Toxicological tests have shown this organo‐copper fungicide to have an oral LD50 (Rats) of 1380 mg kg−1, and it is not mutagenic (Ames negative). Field trials over several seasons have shown crop growth stimulation and yield increases in addition to control of cucurbit wilt and other diseases. This paper summarises trials with HDE for the control of cucurbit wilt.
Fate and persistence of residues on wheat used to explain efficacy differences between deltamethrin suspension concentrate and emulsifiable concentrate formulations
Authors: Hill Bernard D. , Inaba Dan J. 
Published: November 2006

AbstractTo help explain the increased residual activity of a deltamethrin suspension concentrate (SC) formulation against grasshoppers, the persistence, location and nature of residues from the SC and an emulsifiable concentrate (EC) formulation have been compared. Wheat plants were sprayed in a cabinet sprayer at 7.6 g ha−1 for the EC and 5.6 g ha−1 for the SC, then weathered outdoors for 16 days. With the SC formulation, residues were more persistent, more residues were located on the exterior of the leaves, and less deltamethrin was converted to inactive isomers. Eight days after spraying, the exterior deltamethrin residues were 0.13 μg plant−1 from the SC versus 0.06 μg plant−1 from the EC. Thus, more residual deltamethrin is available to grasshoppers with the SC formulation.
Synthesis and fungicidal activity of phenanthridinotriazines: A structure–activity relationship study
Authors: Coghlan Michael J. , Arnold Wendell R. , Caley Blake A. 
Published: November 2006

AbstractA series of analogous tetracyclic 1, 12b‐dihydro‐4H‐1,2,4‐triazino[4,3‐f] phenanthridines and 4H,12bH‐1,2,5‐oxadiazino[5,6‐f]phenanthridines was prepared and tested for control of Erysiphe graminis f. sp. tritici (the causal agent of powdery mildew in wheat). Several analogs showed exceptional activity at doses as low as 6.25 mg litre−1 with substituted analogs VII, X, and XIV being the most potent. Singly substituted tetrahydrotriazinyl or oxadiazenyl rings with lipophilic aromatic components appeared to be the key requirements for optimal powdery mildew control. Substitution of the heterocyclic ring with multiple groups attenuated activity.
The effectiveness of eleven sterol biosynthesis‐inhibiting fungicides against the take‐all fungus, Gaeumannomyces graminis var. tritici, in relation to their physical properties
Authors: Bateman Geoffrey L. , Nicholls Peter H. , Chamberlain Keith 
Published: November 2006

AbstractEleven sterol biosynthesis‐inhibiting fungicides were compared in experiments to determine the physico‐chemical properties required for most effective control of take‐all by soil treatment. All were active in agar culture against an isolate of the pathogen which causes take‐all, Gaeumannomyces grammis var. tritici, with prochloraz being the most toxic (EC50 0.02 μg ml−1) and PP 969 the least (EC50 0.44 μg ml−1). Penconazole and PP 969 had vapour activity against the fungus in further bioassays on agar. In soil in pots, the most strongly lipophilic compound, buthiobate, was ineffective against take‐all in wheat; triadimenol was most effective and, like flutriafol, nuarimol and PP 969, retained some effectiveness after 12 weeks in soil. PP 969, unlike penconazole or nuarimol, was effective in soil treated unevenly by mixing the fungicides in layers. PP 969 is relatively polar, and it is suggested that this property, allowing redistribution in soil water rather than as vapour, outweighed its poor intrinsic toxicity. The ideal soil‐treatment fungicide should therefore be polar and also have good intrinsic activity and moderate persistence. None of the compounds tested had all these properties.