bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thiazole carboxanilide fungicides: A new structure—activity relationship for succinate dehydrogenase inhibitors
Authors: Phillips W. Gary , Rejda‐Heath Joan M. 
Published: November 2006

AbstractStructure‐activity relationships have been examined for a series of thiazole carboxanilides as inhibitors of succinate dehydrogenase. Electron withdrawing and lipophilic effects are important parameters with regard to the anilide ring. Electron‐withdrawing effects along with steric limitations are also important in the thiazole 2‐position. Maximization of this unique structure activity relationship led to the synthesis of the most powerful succinate dehydrogenase inhibitors yet reported. This succinate dehydrogenase inhibitory activity was found to translate directly to high fungitoxicity toward Rhizoctonia solani (Kuhn).
Influence of some nonionic surfactants on water sorption by isolated tomato fruit cuticles in relation to cuticular penetration of glyphosate
Authors: Coret Joël M. , Chamel André R. 
Published: November 2006

AbstractThe effects of several nonionic surfactants on [14C]glyphosate mono(isopropylammonium) diffusion across isolated tomato fruit cuticles (Lycopersicon esculentum Mill.) were compared under controlled atmospheric conditions (25°C; 65% R.H.) using a model system consisting of 1‐μl droplets applied to isolated cuticles on agar blocks. Rates of diffusion for glyphosate (10 g acid equivalent litre−1 in the applied solution) and overall amounts recovered in underlying agar blocks were influenced by the ethylene oxide (EO) chain length for a homologous nonylphenol surfactant series (10 g litre−1). Glyphosate uptake increased with EO content, reaching an optimum at a mean of 17 EO, then decreasing below control values for surfactants with 40 EO. There was a strong influence of the hydrophobe on glyphosate penetration for different surfactants with similar mean EO content (10 EO). The primary aliphatic amine enhanced penetration the most, followed by the nonylphenol while the aliphatic alcohol showed no improvement on glyphosate transfer across cuticles.Water soprtion was greatly enhanced by a primary aliphatic amine (10 EO) and by a nonylphenol (17 EO). The aliphatic alcohol (10 EO) and a shorter‐chained nonylphenol (4 EO) did not significantly enhance water sorption.Comparison of water sorption with glyphosate diffusion across cuticles suggests a strong relationship between the two. Change in solution pH over a limited range had no significant effect.Promotion of cuticular hydration by surfactants may thus play an important role in the enhancement of foliar uptake of water‐soluble herbicides such as glyphosate.
Growth inhibitory and antifeedant effects of azadirachtin on six noctuids of regional economic importance
Authors: Isman Murray B. 
Published: November 2006

AbstractThe comparative efficacy of azadirachtin, the major active ingredient in the botanical insecticide neem, as a larval growth inhibitor and feeding deterrent was determined for six species of noctuids of economic importance: the black army cutworm, Actebia fennica (Tausch.), the bertha armyworm, Mamestra configurata Walker, the variegated cutworm, Peridroma saucia Hubner, the zebra caterpillar, Melanchra picta (Harr.), the Asian armyworm, Spodoptera litura (Fab.), and the cabbage looper, Trichoplusia ni Hubner. When added to an artificial diet, azadirachtin inhibited neonate larval growth of all species in a dosedependent fashion. EC50 values (dietary concentration reducing larval growth by 50% relative to controls) following ten days of feeding ranged from 0.12 to 0.24 mg kg−1 but without significant differences between species. However, when second‐instar larvae were offered a choice, only larvae of P. saucia and S. litura discriminated between a control diet and diet containing azadirachtin at concentrations up to 0.4 mg kg−1. A more sensitive behavioural bioassay using fourth‐instar larvae indicated that S. litura was the most sensitive to the antifeedant effects of azadirachtin (EC50 = 1.25 ng cm−2), whereas A. fennica was the least (EC50 = 40.7 ng cm−2). Topical treatment of fourth‐instar larvae with 50 or 100 ng of azadirachtin resulted in significant inhibition of subsequent growth, diet consumption, and dietary utilization. However, A. fennica and S. litura are less inhibited that the other four species. The present study indicates that behaviourbased bioassays alone do not characterize the total effect of azadirachtin on noctuid larvae.
Adjuvants and volatility of hormone herbicides
Authors: Schubert Christine L. , Erasmus Daniel J. , Van Dyk Louis P. , Gray Vincent , Lovell Kevin 
Published: November 2006

AbstractThe aim of this study was to develop a rapid and reliable method for detecting the effect of adjuvants on the volatility of herbicides and to assess the efficacy of locally available adjuvants. Bioassays, using seed germination, were unsatisfactory for assessing the reduction of the volatility of the iso‐octyl ester of 2,4‐dichlorophenoxyacetic acid (2,4‐D IOE) by adjuvants.Field trials and parallel trials under controlled conditions, together with chromatographic analyses of trapped herbicide vapour, were effective in assessing the efficacy of adjuvants. The adjuvants used were: a molasses‐based developmental sample of a feeding attractant and antidrift agent; a wax emulsion contributing to control of droplet size; an anionic gel‐based sticker and spreader made from kelp; an alkoxylated‐fatty alkylamine polymer marketed as a wetter and penetrator; an aqueous dispersion of waxes and surfactants which reduces drift and evaporation; a polyvinyl polymer for drift reduction; an emulsifiable beta‐pinene polymer and two different formulations of an adjuvant with buffering action. Experimental grass plots were sprayed with herbicide with or without adjuvants (used as controls). 2,4‐D vapour in the air above the plots was sampled and analysed by gas chromatography. Field trial results indicated that weather factors influenced the volatility of 2,4‐D IOE and that only the polyvinyl polymer decreased volatility for the duration of the trial. The adjuvant consisting of a dispersion of waxes and surfactants had no effect on the volatility of 2,4‐D IOE. The molasses‐based, wax emulsion, and beta‐pinene polymer‐based adjuvants caused an initial increase in 2,4‐D IOE vapour, but the volatility decreased after two hours. Trials performed in a portable glasshouse showed similar results, and also showed that a new formulation of an existing adjuvant with buffering action reduced volatility.
Design and synthesis of 5,6‐dihydro‐4H‐1,3,4‐oxadiazines as potential octopaminergic insecticides
Authors: Dekeyser Mark A. , Harrison W. Ashley , McDonald Paul T. , Downer Roger G. H. 
Published: November 2006

AbstractA novel class of insecticides, the dihydrooxadiazines, was proposed following the use of molecular modelling techniques. These compounds represent conformationally restricted analogues of octopamine. Eight dihydrooxadiazines were synthesized and evaluated for useful insecticidal properties. Several of these compounds demonstrated activity against rice planthoppers, mite eggs, and tobacco budworm eggs.
Biological monitoring of workers occupationally exposed to organophosphorus pesticides
Authors: Nutley Bernard P. , Cocker John 
Published: November 2006

AbstractThis paper describes the development and use of a biological monitoring method for assessing exposure to organophosphorus pesticides. The method is used to determine the concentration of six dialkyl phosphates and phosphoro‐thioates (dimethyl phosphate, diethyl phosphate, O,O‐dimethyl phosphorothioate, O,O‐diethyl phosphorothioate, O,O‐dimethyl phosphorodithioate and O,O‐diethyl phosphorodithioate) in urine. The method involves the azeotropic distillation of urine, derivatisation of the residue with pentafluorobenzylbromide followed by high resolution gas chromatography with flame photometric detection.The technique has been applied to the analysis of over 400 urine samples obtained from 140 workers with potential occupational exposure to organophosphorus pesticides during various agricultural activities, sheep dipping or pesticide formulation. Wherever possible, blood samples were taken for measurement of red blood cell and plasma cholinesterase activity. The results show that in over 300 instances where blood samples were also obtained, urinary dialkyl phosphate metabolites could be detected even though there was no depression of red cell or plasma cholinesterase activity. Formulation workers had higher urinary metabolite levels (expressed as nmoles metabolite per mmole creatinine) than any of the other groups studied and were the only group where a significant reduction in cholinesterase activity was also seen.The results discussed here show that the method for the analysis of urinary dialkyl phosphate metabolites described is useful for monitoring occupational exposure to organophosphorus pesticides and is capable of detecting low levels of exposure not detectable by depression of cholinesterase activity.
Pesticidal compounds from higher plants
Authors: Benner Jill P. 
Published: November 2006

AbstractHigher plants offer an excellent source of biologically active natural products. Over the centuries numerous plants have been exploited as sources of insecticides, but nowadays traditional botanical insecticides play only a minor role in world agriculture. Nevertheless, plant natural products still have enormous potential to inspire and influence modern agrochemical research.Few plant natural products will ever reach the market as products per se, but others will provide lead structures for programmes of synthetic chemistry and hopefully follow the success story of the synthetic pyrethroids. Structurally complex compounds, which are not amenable to synthetic chemistry programmes, may also have a role to play by validating new modes of action for pesticides.Examples are presented of compounds exhibiting insecticidal, fungicidal and herbicidal effects. Consideration is also given to the development of screening programmes to detect new compounds with interesting biological properties. Careful experimental design and thorough recording of procedures and data are crucial to success. Badly designed programmes afford only weakly active compounds or show effects which cannot be reproduced at a later date.Natural product chemistry, whether based on higher plants, micro‐organisms or other sources, is a very difficult science, but there is little doubt that dedicated research will eventually be rewarded with exciting new lead structures for industrial application.
Genetically engineered viral insecticides: New insecticides with improved phenotypes
Authors: Possee Robert D. , Cayley P. Jane , Cory Jenny S. , Bishop David H. L. 
Published: November 2006

AbstractBaculoviruses are natural pathogens of insects which have been used as biopesticides. In contrast to many chemical agents, baculoviruses affect only a limited number of insects and so can be used to target particular insect species. Unfortunately, unless the host receives a very high virus dose, the insect continues to feed and causes damage to crops, because the virus takes several days to kill it. This lag is unacceptable in the protection of many crops, especially where cosmetic damage seriously reduces the value of a crop (e.g. fruit). Strategies have been devised recently to circumvent this problem. The baculovirus genome has been modified, using genetic engineering techniques, to incorporate foreign genes encoding insect‐specific toxins, or hormones or enzymes. Expression of some of these genes in the virus‐infected host insect has been shown to reduce both the feeding damage to crop plants and the time taken to kill the insect pest. The current status of this developing field is described, together with an assessment of the possible risks involved in using such genetically modified agents in the environment.
Uptake and translocation of bleaching herbicidal compounds in radish seedlings
Authors: Takahashi Masahiro , Kawamura Shinichi , Miyakado Masakazu , Sanemitsu Yuzuru , Tanaka Shizuya 
Published: November 2006

AbstractThe relationship between the hydrophobicity of certain herbicidal compounds and the bleaching pattern caused on radish cotyledons was investigated. Seed treatment with diphenylpyridones, as well as with established herbicides, produced three types of bleaching pattern according to their hydrophobicity. The less hydrophobic compounds caused complete bleaching of both cotyledons, but the compounds with more hydrophobicity caused only partial bleaching. The critical points for whole or partial bleaching were in the range of log Kow 4–5 (Kow: octanol/water partition coefficient), and these values were changed slightly with their chemical classes. Uptake of compounds into the seed coat took place rapidly; these compounds were then translocated slowly from the seed coat to the embryo, namely, radicle, abaxial surface of one cotyledon and marginal areas of both cotyledons.Application of these compounds to roots resulted in initial translocation to marginal areas of both cotyledons, with subsequent translocation to the middle area. It is believed that compounds taken up into the radicle were translocated to both cotyledons in a manner similar to that following application to roots. These effects following uptake by seeds can be used as a translaminal and lateral transport assay for bleaching herbicidal compounds in cotyledons.
Effects of alcohols, glycols and monodisperse ethoxylated alcohols on mobility of 2,4‐D in isolated plant cuticles
Authors: Schönherr Jörg 
Published: November 2006

AbstractEffects of n‐alcohols, ethoxylated alcohols and glycols on mobility of 2,4‐dichlorophenoxy acetic acid (2,4‐D) in cuticular membranes (CM) isolated from bitter orange (Citrus aurantium L.) leaves were studied. 1‐Heptanol, 1‐octanol and 1‐nonanol had the highest effects, as they increased solute (2,4‐D) mobility by 25‐ to 30‐fold. Increasing the number of carbon atoms in the alcohols decreased their effectiveness. Ethoxylation of alcohols did not increase 2,4‐D mobility and effectiveness decreased with increasing ethoxylation. Free glycols had no effect on solute mobility in isolated cuticles. The results show that ethoxylation is not required for increasing solute mobility in cuticles. It is suggested that alcohols and ethoxylated alcohols are sorbed in cuticular waxes and plasticize them. The data show that alcohols and ethoxylated alcohols having between seven and ten carbon atoms are powerful accelerator adjuvants, as long as the degree of ethoxylation is not too high. Free short‐chain alcohols synthesized by leaves may act as endogenous plasticizers and modulate permeabilities of cuticles, depending on environmental and growing conditions.
Influence of pesticides on the activity and kinetics of invertase, urease and acid phosphatase enzymes
Authors: Gianfreda Liliana , Sannino Filomena , Filazzola Maria T. , Violante Antonio 
Published: November 2006

AbstractThe effects of four pesticides (three herbicides, atrazine, paraquat, glyphosate, and an insecticide, carbaryl) on the activity and kinetics of an invertase (from yeast), a urease (from jack bean) and an acid phosphatase (from potato) were investigated. Glyphosate and paraquat showed a marked activation effect on invertase activity. From the dependence ofVmaxandKmparameters on pesticide concentrations, a mixed‐type activation mechanism was suggested. The kinetic behaviour of urease and acid phosphatase appeared to be uninfluenced by both pesticides.Methanol, used as solvent for both carbaryl and atrazine, inhibited invertase, urease and acid phosphatase with, respectively, competitive, non‐competitive and uncompetitive mechanisms. The extent of the inhibition was different, as estimated by the values of the inhibition constantK1. An additional inhibition effect of urease and invertase activities was achieved in the presence of carbaryl, whereas no influence was detected on the activity and kinetics of acid phosphatase. Finally, atrazine was shown to alter the kinetics of the enzymes only at higher concentrations.
Effects of triazole inhibitors of sterol biosynthesis on the free and esterified sterol composition of celery cell suspension cultures
Authors: Yates Philip J. , Lenton John R. , Goad L. John 
Published: November 2006

AbstractTreatment of celery cell suspension cultures with paclobutrazol and three other triazoles resulted in decreased growth and an accumulation of 14α‐methylsterols in both the free sterol and the steryl ester pools, thus indicating that the triazoles were inhibiting the action of the plant obtusifoliol 14α‐demethylase system. Obtusifoliol, 14α‐methylcampesta‐8,24(241)‐dien‐3β‐ol and 14α‐methylcampest‐8‐en‐3β‐ol were the main 14α‐methylsterols to increase in the free sterol pool. In the presence of the triazoles the steryl esters became virtually depleted of sitosterol, campesterol, stigmasterol and isofucosterol, which were replaced by 14α‐methylsterols with obtusifoliol becoming the dominant esterified sterol. Treatment of the celery culture with a fourth triazole which did not have a noticeable effect on growth and caused negligible accumulation of 14α‐methylsterols in the free sterol pool nevertheless produced some enrichment of the steryl esters in obtusifoliol. The results indicate that, following triazole treatment, a rapid esterification of the accumulating 14α‐methylsterol intermediates occurs before they start to build up in significant amount in the free sterol pool.
Effects of pyroquilon on the infection process of Monilinia laxa causing peach twig blight
Authors: De Cal Antonieta , Melgarejo Paloma 
Published: November 2006

AbstractThe capacity of Monilinia laxa (Aderh. et Ruhl.) Honey to induce peach twig blight was lost in an albino mutant and in a wild‐type strain of the pathogen treated with pyroquilon, a melanin biosynthesis inhibitor. Pyroquilon (10 ù ml−1) inhibited melanin biosynthesis but did not inhibit mycelial growth of the pathogen or the albino mutant in vitro. These observations indicate that the compound interferes in some manner with the infection process of host cells.
Evaluation of a pelleted bait containing methyl anthranilate as a bird repellent
Authors: Mason J. Russell , Clark Larry , Miller Timothy P. 
Published: November 2006

AbstractNo‐till agriculture involves the use of granular pesticide formulations, chemically treated seeds, and pelleted baits. Some of these may accidentally kill birds. We have tested whether methyl anthranilate (MA), a known bird repellent, would eliminate consumption of a pelleted bait. In two laboratory experiments and an outdoor aviary trial, cowbirds (Molothrus ater Bodd.) were presented with pellets containing pesticide and MA, pellets containing pesticide but no MA, and carrier pellets without pesticide or MA. Consumption of any formulation was low, but the addition of MA significantly decreased bait loss in the laboratory, and prevented the disappearance of bait in the outdoor trial.
Acute toxicity of the bird repellent, methyl anthranilate, to fry of Salmo salar, Oncorhynus mykiss, Ictalurus punctatus and Lepomis macrochirus
Authors: Clark Larry , Cummings John , Bird Steven , Aronov Eugeny 
Published: November 2006

AbstractSeveral laboratory and field studies have shown methyl anthranilate to be an effective, non‐toxic and non‐lethal bird repellent, with application potential for protecting crops, seeds, turf and fish stocks from bird damage. Furthermore, methyl anthranilate can be added to liquids for the purposes of protecting migratory birds, e.g. addition to waste water associated with mining and to standing water pools at airports. Mammalian toxicity data are favorable. Methyl anthranilate is used as a fragrance and food flavoring and is GRAS listed by the US Food and Drug Administration. Despite the favorable outlook for methyl anthranilate's use as a safe repellent, no data exist on its environmental fate and effects. We have tested the acute toxicity of methyl anthranilate in a static system against the fry of four species of fish. The LC50 at 24 h for Atlantic salmon (Salmo salar L.) was 32.3 mg liter−1, with the no observable effect limit at 6 mg liter−1. The LC50 at 24 h for rainbow trout (Oncorhynus mykiss Richardson) was 23.5 mg liter−1, with the no observable effect limit at 5 mg liter−1. The LC50 at 24 h for channel catfish (Ictalurus punctatus Raf.) was estimated to be 20.1 mg liter−1, with the no observable effect limit at 7 mg liter−1. The LC50 at 24 h for bluegill sunfish (Lepomis macrochirus Raf.) was estimated to be 19.8 mg liter−1, with the no observable effect limit at 7 mg liter−1..
Selection and characterization ofPhytophthora parasiticamutants with ultraviolet‐induced resistance to dimethomorph or metalaxyl
Authors: Chabane Kamel , Leroux Pierre , Bompeix Gilbert 
Published: November 2006

AbstractMutants ofPhytophthora parasiticaDast. more or less resistant to dimethomorph or metalaxyl were obtained by treating mycelium with ultraviolet radiation. Some metalaxyl‐resistant mutants exhibited levels of resistance (i.e. the ratio between the EC50values for the mutant and the wild‐type strain) greater than 100, but those observed in the dimethomorph‐resistant mutants never exceeded 25. Most mutants retained their resistance after sub‐culturing on unamended agar medium. Single zoospore clones derived from a metalaxyl‐resistant and a dimethomorph‐resistant mutant, selected as amongst the most resistant, had levels of resistance similar to those of the parental strains. The metalaxyl‐resistant mutants were also resistant to the related phenylamide fungicides, furalaxyl and benalaxyl, but remained sensitive to dimethomorph. The dimethomorph‐resistant mutants were not resistant to phenylamide fungicides. The pathogenicity of some metalaxyl‐ or dimethomorph‐resistant mutants on tobacco leaves was similar to that of the wild‐type strains.
Potential of natural peptidic compounds as leads for novel pesticides
Authors: Bland John M. , Edwards J. Vince , Eaton Scott R. , Lax Alan R. 
Published: November 2006

AbstractStructure‐activity relationship (SAR) studies of the natural pesticidal peptide, tentoxin, are described in the context of similarity between pharmaceutical and agricultural methods of developing biologically active peptidomimetics. Essential residue substitutions that confer biological activity through predictable conformational changes in the peptide backbone and side chain functionalities are discussed. A combination of molecular modelling studies and the biological activity of natural, synthetic and photochemically transformed analogs of tentoxin is utilized to further the understanding of structural and conformational requirements for biological activity.
Behavioural responses ofAphis fabaeto isothiocyanates in the laboratory and field
Authors: Isaacs Rufus , Hardie Jim , Hick Alastair J. , Pye Barry J. , Smart Lesley E. , Wadhams Lester J. , Woodcock Christine M. 
Published: November 2006

AbstractIsothiocyanates have been shown to stimulate olfactory receptors on the antennae of the black bean aphid,Aphis fabaeScop. Single‐cell recording techniques show that this aphid has receptors at the proximal primary rhinarium which are sensitive to n‐butyl isothiocyanate. In laboratory assays, 4‐pentenyl and n‐butyl isothiocyanates were repellent at similar threshold concentrations.A. fabaewas attracted to host‐plant odour, but addition of either isothiocyanate to the airstream masked this attraction. Field trials on spring beans did not produce any consistent reduction in numbers of alate or apterous aphids on the crop, and yields were not improved by either compound.