bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variable resistance factors of fungicides acting as sterol demethylation inhibitors
Authors: Köller Wolfram , Wubben Jos P. 
Published: November 2006

AbstractThe ED50 values and resistance factors of 20 fungicides that all act as inhibitors of the C‐14 demethylation of 24‐methylenedihydrolanosterol were determined for one wild‐type and four resistant strains of Ustilago avenae. All fungicides were cross‐resistant to each other; however, the resistance factors varied considerably, ranging from 50 (triadimenol) to 2·2 (miconazole). A tentative structural requirement for low resistant factors was the presence of two phenyl rings separated from each other by at least three atoms. Labeling of lipids with [14C]acetate in the absence and presence of the inhibitors and subsequent sterol analysis revealed that the variable resistance factors were not related to the presence of a second target site. In spite of reported second modes of action of fenarimol, tebuconazole or miconazole, accumulation of C‐14 sterol precursors in both sensitive and resistant isolates was necessary to accomplish growth inhibition.
The lipid compositions of two isolates of Cladosporium cucumerinum do not explain their differences in sensitivity to fungicides which inhibit sterol biosynthesis
Authors: Carter Geoffrey A. , Kendall Sheila J. , Burden Raymond S. , James Carolyn S. , Clark Terence 
Published: November 2006

AbstractIsolate 840905 of Cladosporium cucumerinum, when grown on agar or in liqiud medium, was sensitive to triadimenol, HWG 1608 (tebuconazole), fenpropimorph and pimaricin but relatively resistant to terbinafine. Conversely, isolate 49628 was sensitive to terbinafine but relatively resistant to the other fungicides. Changes in sterol composition following treatment with the fungicides reflected the known modes of action of each fungicide. When individual enantiomers of triadimenol were tested against isolate 840905 the order of activity in reducing mycelial growth was 1 S, 2R > 1R, 2R > 1R, 2S ≈︁ 1S, 2S, and this was paralleled by the depletion of ergosterol and the appearance of 14α‐methyl sterols. Isolate 49628 had a greater saturated:unsaturated fatty acid ratio than did isolate 840905 but no major changes in fatty acid composition of either isolate were induced by fungicide treatment. There appears to be no obvious explanation for the differences in fungicide sensitivity of the isolates in terms of their lipid compositions.
The effect of sublethal doses of cypermethrin on Egg laying of mustard beetle (Phaedon cochleariae (F.))
Authors: Hajjar Mohammad J. , Ford John B. 
Published: November 2006

AbstractDiluted cypermethrin EC was sprayed on to radish plants in the laboratory and its toxicity to mustard beetle was assayed. Doses at or below an equivalent of 3g ha−1 (LD6) were used to measure sublethal effects. A substantial reduction in egg laying occurred even at doses as low as 1 and 1.5 g ha−1. This was due to two factors, the toxicity factor and the antifeeding factor. Insects showing sublethal symptoms of poisoning laid fewer eggs, the reduction being proportional to the dose. On treated leaves, oviposition behaviour was abnormal, eggs being laid on the surface instead of in niches excavated by the female. Feeding was reduced on treated leaves and a positive correlation was demonstrated between the amount of feeding and the proportion of eggs laid in niches. A reduction in hatching occurred when eggs were not laid in niches.Doses of 3 g ha−1 killed the first instar larvae even seven days after application. The effects on adult feeding and oviposition of a sublethal dose of 3 g ha−1 persisted for a period up to 20 days post‐treatment.
Metabolism of phenyl‐3 H‐indoles by cell suspension of Acer pseudoplatanus L. and their phytotoxicity
Authors: Bastide Jean , Carre Philippe , Gomez Francis , Greiner Alfred 
Published: November 2006

AbstractPhenyl‐3H‐indoles inhibited growth of Acer pseudoplatanus cells but were not toxic in vivo. Experiments were conducted to find out why the compounds gave a toxic response in cell suspension but not a phytotoxic response in whole plants. The behaviour of two phenyl‐3H‐indoles, (2‐(4‐chlorophenyl)‐3,3‐dimethyl‐5‐fluoro‐3H‐indole and 2‐(4‐chlorophenyl)‐3,3‐dimethyl‐5‐carboxy‐3H‐indole), was investigated in cell suspensions. Absorption and metabolism by cells were rapid. The major metabolite was identified as a polar conjugate of 2‐(3‐hydroxy‐4‐chlorophenyl)‐3,3‐dimethyl‐5‐fluoro‐3H‐indole. This metabolite did not inhibit cell growth. Different phenyl 3H‐indole analogues with the hydroxylation site blocked were synthesised to determine if metabolism was involved in the disappearance of activity in vivo. The results indicated that this was not the case and thus the absence of phytotoxicity must be related to another factor.
Dual effects of dichlorvos on the synaptic transmission in the sixth abdominal ganglion of the cockroach Periplaneta americana
Authors: Lapied Bruno , Vanel Jacques , Hue Bernard 
Published: November 2006

AbstractThe effects of the organophosphate insecticide dichlorvos were studied on the cercal‐afferent giant‐interneurone synapses in the sixth abdominal ganglion of the cockroach Periplaneta americana, using the single‐fibre oil‐gap method. When compared to eserine, dichlorvos showed a dose‐dependent anticholinesterase effect.Both eserine (10−7 M) and dichlorvos (2 × 10−8 M) increased the amplitude and duration of the composite excitatory postsynaptic potential and acetylcholine potential, an effect corresponding to the well‐known anticholinesterase one. However, during the prolonged action of these compounds, a subsequent decrease of the composite excitatory postsynaptic potential amplitude occurred, whereas the amplitude and duration of the acetylcholine potential continued to increase. The secondary effect (a decrease of composite excitatory postsynaptic potential amplitude) might be attributed to a direct action of the non‐hydrolysed acetylcholine remaining in the synaptic cleft on presynaptic acetylcholine muscarinic receptors, reducing the acetylcholine release by a negative feedback mechanism or to a direct action of dichlorvos on presynaptic and postsynaptic acetylcholine receptors.
Dominant rhizosphere bacteria as a source for antifungal agents
Authors: Lievens Katelijn H. , van Rijsbergen Ronan , Leyns Frederik R. , Lambert Bart J. , Terming Paul , Swings Jean , Joos Henk J.‐P. 
Published: November 2006

AbstractA search for micro‐organisms associated in high numbers with roots or leaves of corn, grapevine, chicory, soybean, sunflower, barley and sugarbeet yielded a collection of over 10 000 bacterial strains. Within this collection, antifungal strains have been selected, using direct or indirect in‐vitro assays against one target fungus per crop. The target fungi were selected based on their agronomic relevance as pests.Isolates with antifungal activity were tested for their spectrum of activity against a set of phytopathogenic fungi. In 15 bacterial strains with broad‐spectrum activity, belonging to the species Erwinia herbicola. Serratia plymuthica, Pseudomonas fluorescens, P. aureofaciens, P. cepacia and Bacillus subtilis, the active compounds have been identified. Bacterial strains belonging to the same taxon, but isolated from different ecological niches and/or different places in Europe, produce identical compounds. In two bacterial taxa (Erwinia and Serratia) this was reflected in a genetic conservation of the regions coding for antifungal activity. In both cases, the biosynthetic pathways proved to be genetically complex.All of the compounds identified in this study have been described previously in bacterial strains isolated from analogous or completely different ecosystems.
Genetically engineered viral insecticides–A progress report 1986 1989
Authors: Bishop David H. L. 
Published: November 2006

AbstractAmong the viruses that are pathogenic for insect species, baculoviruses have been shown to be useful as insecticides for pest control. In some cases they have been used as cost‐effective and environmentally acceptable alternatives to chemical insecticides. However, because viruses need to be ingested and replicate extensively in their host before they kill it, baculovirus insecticides are much slower than chemicals or other reagents that kill insects either on contact or shortly after ingestion. The objective of the programme of genetic engineering of baculovirus insecticides is to improve their speed of action while maintaining their host specificity and other attributes that make them desirable alternatives to chemical pesticides.Since 1986 four field releases have been undertaken involving genetically engineered baculovirus insecticides. The first release used a genetically marked Autographa californica nuclear polyhedrosis virus (AcNPV). The study began in 1986 and was terminated in 1987. The results demonstrated that an innocuous piece of DNA, appropriately positioned in the AcNPV genome, was an effective means to tag the virus without affecting its phenotype, allowing it to be identified in bioassays of plant and soil samples. The second release, in 1987, involved a genetically marked virus from which the gene coding for the protective polyhedrin protein of the virus had been removed. The field data obtained with this virus showed that it did not persist in the environment, neither in soil, nor on vegetation, nor in the corpses of caterpillars. The third and fourth releases were undertaken in 1988. For one of these studies the marked, polyhedrin‐negative virus was again used. In the other study a polyhedrin‐negative virus that contained a junk' (/?‐galactosidase) gene was employed.
In‐vitro evidence for activative thiolysis and selfsynergism of sulfenyl dicarbamate derivatives of 3,4 methylenedioxyphenyl N‐methylcarbamate
Authors: Wallace Guillermo C. , Zerba Eduardo N. 
Published: November 2006

AbstractActivative thiolytic cleavage of the N‐S bond and self‐synergism in sulfenyl dicarbamate (SD) derivatives of 3,4‐methylenedioxyphenyl N‐methylcarbamate has been investigated. The formation of precursor carbamates by the reaction of the propoxur derivative with glutathione and cysteine was demonstrated by HPLC.The slower rate of insectidal action of SD‐propoxur compared with propoxur and its lower ki for inhibition of housefly acetylcholinesterase measured after preincubation of housefly head homogenate with N‐ethylmaleimide were considered as indirect evidence of the N‐S breakdown as a delay factor in toxicity.The SD‐carbaryl derivative, 3,4‐methylenedioxyphenyl N‐methylcarbamate, and piperonyl butoxide similarly inhibited the oxidative metabolism of [14C]carbaryl in post‐mitochondrial homogenates of housefly abdomens. The results indicated that activative thiolysis and self‐synergism performed by the methylenedioxyphenyl group could be processes involved in the insecticidal action of the sulfenyl dicarbamates.
Structure‐activity‐residue relationships of alkylphenol polyoxyethylene non‐ionic surfactants and MSMA
Authors: Falk Richard H. , Bayer David E. , Hess F. Dan 
Published: November 2006

AbstractThe influence of alkylphenol polyoxyethylene non‐ionic surfactants on the distribution pattern of MSMA (sodium hydrogen methylarsonate) was studied using scanning electron microscopy and X‐ray microanalysis elementmapping techniques. Surfactant concentrations and lipophilic–hydrophilic constitution influenced phytotoxicity and residue patterns. Surprisingly, the percentage of leaf surface covered bore little correlation to phytotoxicity.
Sequential latent effects of a sub‐lethal dose of ivermectin in Calliphora vomitoria L.
Authors: Strong L. 
Published: November 2006

AbstractA single sub‐lethal dose of 0‐3 μg ivermectin applied topically to third (last) instar larvae of Calliphora vomitoria prevents a significant number of adult flies from escaping from their puparia after metamorphosis, although the flies show no signs of physical abnormality. Of the insects that manage to emerge, a significant number of females do not develop mature oocytes. Ivermectin in sub‐lethal doses seriously impairs post‐embryonic development in Calliphora at four independent levels: interference with pupariation, suppression of adult head development, inhibition of emergence from the puparium, and disruption of ovarian development in the adult female. These findings are discussed in relation to ivermectin's efficacy as a pesticide and particularly to non‐specific effects upon dung‐inhabiting insects.
Characteristics of pyrethroids for insect pest control in agriculture
Authors: Hirano Masachika 
Published: November 2006

AbstractPyrethroid insecticides are characterised by high knockdown and lethal activity, a wide spectrum, good residual activity, together with repellent and antifeeding activity. With these characteristics, pyrethroid insecticides have become widely used for plant protection. Their major use has been for the control of bollworms and leafworms in cotton but they have also achieved widespread use for controlling various species of lepidopterous pests in fruits and vegetables, aphids in cereals, and many other minor outlets. Although the early synthetic pyrethroids suffered from a lack of activity against mites and soil pests, later additions, such as fenpropathrin, have combined high acaricidal activity with insecticidal activity and further pyrethroids are being introduced for use in soil.The extent of pyrethroid use has increased progressively since the first of the ‘photostable’ pyrethroids was registered. In 1986, the market share of pyrethroids reached 25 % of the total insecticide market for plant protection; this figure can be increased in the future.
Pyrethroids and the economics of pest management
Authors: Watkinson Ian A. 
Published: November 2006

AbstractPyrethroid insecticides effect excellent control of a wide range of insect pest species at low cost to the user. In outlets where a broad spectrum of pests occur, alternative compounds are often more expensive and frequently have to be combined to provide an acceptable spectrum of control. The benefits of the pyrethroids have led to their extensive and often exclusive use in many of these outlets around the world. However, such dependency on a single class of chemistry brings with it the attendant threat of resistance. Pyrethroid resistance has now been documented in many species of insect around the world and for several of these, changing to other insecticides has meant large increases in the cost of control programs.Analysis of the US insecticide market has shown that in 1987 the average insecticide cost to a mid‐south cotton grower was $32 acre−1 (1 acre = 0‐405 ha). A hypothetical case was examined where resistance to the pyrethroids occurred in one key pest, Heliothis virescens, the tobacco budworm. The level of resistance was defined such that 50 % of the normally pyrethroid‐treated area was now treated with the most cost‐effective alternative. Under these conditions, a mid‐south grower would see the cost of insect control nearly double to $61‐50 acre.Extrapolating such increases to the whole US cotton crop or to global cotton production would lead to increased insecticide costs of $230 × 106 and $1‐4 × 109 per year, respectively. Making similar assumptions for all crops, the increased global costs of only a moderate amount of pyrethroid resistance could be as high as $2‐4 × W9 annually. There is, thus, a very real need to maintain the pyrethroids as effective insect‐control agents for as long as possible.
Formulation of insect controlling agents with β‐cyclodextrin
Authors: Szente Lajos , Magisztrak Halina , Szejtli Jozsef 
Published: November 2006

AbstractTwo insecticides, an insect repellent and an insecticide synergist have been complexed with β‐cyclodextrin yielding microcrystalline, wettable, non‐hygroscopic formulations. The insecticides fenitrothion and malathion, the repellent diethyltoluamide and the synergist MGR‐264 were found to form stable inclusion complexes with β‐cyclodextrin.The molecular encapsulation resulted in improved heat and chemical stability, storability, enhanced wettability and dissolution properties of these rather volatile, poorly water‐soluble agents.
Selection for abamectin resistance in colorado potato beetle (coleoptera: Chrysomelidae)
Authors: Argentine Joseph A. , Clark J. Marshall 
Published: November 2006

AbstractThere was no difference in dose response to abamectin between a laboratory strain of Colorado potato beetle (Leptinotarsa decemlineata (Say))from North Carolina and a multiple resistant strain from Massachusetts (LD50= 1.95 and 1.98 ng larva−1, respectively). Two abamectin‐resistant strains were generated by separate means. The mutagen, ethyl methanesulfonate, was used to generate an abamectin‐resistant strain (LD50= 29.4 ng larva−1) from the susceptible laboratory strain. The other resistant strain (LD50 = 45.3 ng larva−1) was generated through an intense selection with abamectin of a field strain contained in cages set up in existing potato fields. Resistance ratios calculated from LD50values for the two abamectin‐resistant strains were 15‐fold and 23‐fold, respectively. Resistance ratios calculated from LD97values (21‐fold and 38‐fold, respectively) were higher than those calculated at LD50. Also, there were larvae in both resistant strains which were capable of surviving doses up to 100 ng larva−1, while the susceptible strain had no survivors at 10 ng larva−1. Although the logit mortality regression analysis produced statistically different lines for the two abamectin‐resistant strains, the slopes of each appear to be the same. Both resistance factors were determined to be autosomal and incompletely recessive (0.26 to 0.4, respectively) via reciprocal F1crosses to the susceptible laboratory strain.
Residues of the herbicide tri‐allate in preplant and pre‐emergence treated triticale (X triticosecale wittmack) determined by gas chromatography
Authors: Cessna Allan J. 
Published: November 2006

AbstractResidues of tri‐allate in triticale (X Triticosecale Wittmack) were determined, after both preplant and pre‐emergence soil‐incorporated applications of tri‐allate at 1.4 kg ha−1, at the following crop stages: 2–3‐leaf, 5–6‐leaf, fully headed and mature (straw and grain). Tri‐allate residues were detected only in green tissue samples from the 2–3‐leaf stage of the crop. Recoveries of tri‐allate were in the order of 90 and 85 % from the green tissue and grain at the 100 and 50 μg kg−1fortification levels, respectively.
Effects of pesticides upon nitrogen fixation and nodulation by dry bean
Authors: Schnelle Michael A. , Hensley David L. 
Published: November 2006

AbstractThe effects of seven fungicides, seven herbicides and six insecticides on nitrogen fixation and nodulation by the dry bean (Phaseolus vulgaris L. cv “Bonus”) were investigated. All pesticides examined were found innocuous to nitrogen fixation (acetylene reduction) except bentazone, a post‐emergence herbicide. Bentazone at 3 × label rate (6.7 kg ha−1) consistently depressed nitrogen fixation rates within 48 h after application. However, rates recovered and were comparable to those of control plants after 6 days. No effects were observed on nodulation from any of the pesticides (3 × or label rate) applied.
A new resistance to pyrethroids in tribolium castaneum (herbst)
Authors: Collins Patrick J. 
Published: November 2006

AbstractThe characteristics of a new high‐level, field‐derived resistance to pyrethroids in Tribolium castaneum (Herbst) were investigated using impregnated‐paper and treated‐grain assays.Piperonyl butoxide almost completely suppressed the resistance, suggesting that the major resistance mechanism was microsomal oxidation. Resistance extended to all pyrethroids tested and to carbaryl but not to organophosphorus insecticides or to methoprene. Resistance was strongest against α—CN phenoxybenzyl cyclopropanecarboxylate pyrethroids and was correlated with structural modifications of the pyrethroid molecule, results also consistent with oxidative resistance.This resistance will ultimately result in failures to control T. castaneum if pyrethroids, such as deltamethrin, cypermethrin or cyfluthrin, are used in the field, even if they are synergised with piperonyl butoxide. The resistance does not jeopardise organophosphorus materials (e.g. fenitrothion, chlorpyrifos‐methyl, pirimiphos‐methyl, methacrifos) or methoprene.
Effect of diclobutrazol on the growth and sterol and photosynthetic pigment content of winter wheat
Authors: Khalil Iqtidar A. , Mercer E. Lan 
Published: November 2006

AbstractThe effect of the fungicide, diclobutrazol, on the germination, growth, chloroplast pigment and sterol content of winter wheat seedlings has been studied. At 250 μEm it retards their germination and growth, producing smaller, darker green and apparently healthy young plants. This is largely due to the 2S,3S–enantiomeric component. The increased greenness is not due to a direct effect on chloroplast pigments. It inhibits sterol 14—demethylation, causing an increase in the content of 4α,14α–dimethyl sterols, and also increases the proportion of campesterol, a 24—methyl sterol, relative to that of the 24—ethyl sterols, stigmasterol and sitosterol. Both the 2R,3R– and 2S,3S–enantiomers appear to be able to cause these changes in sterol content.
Tracing a 14C‐labeled carbamate molluscicide through the digestive system of deroceras reticulatum (müller)
Authors: Triebskorn Rita , Künast Christoph , Huber Rolf , Brem Gerd 
Published: November 2006

AbstractThe passage of a 14C‐labeled carbamate, 2‐(2‐chloro‐1‐methoxy‐' ethoxy)phenyl N‐methylcarbamate, or its labeled metabolites through the alimentary system of the grey garden slug Deroceras reticulatum was examined by autoradiographic studies and scintillation counting. It was demonstrated that, in a first step, the molluscicide penetrated the cells of the oesophagus and the crop. It was quickly transported by the hemolymph to the periphery of the body and re‐entered the cells of the digestive tract and the mid‐gut gland in a second step from the hemolymph side. The crypt cells of the mid‐gut gland are discussed as cells involved in detoxification, and connective tissue cells as the major storage sites of the labeled material. Excretion in feces and secretion in mucus are thought to be the routes of 14C elimination.
Nematicidal activity of some essential plant oils
Authors: Sangwan Naresh K. , Verma Braham S. , Verma Kailash K. , Dhindsa Kuldip S. 
Published: November 2006

AbstractNematicidal activity of the essential oils of different plant species belonging to the families Labiatae (Ocimum basilicum, Ocimum sanctum and Mentha piperata), Myrtaceae (Callistemon lanceolatus and Eugenia caryophyllata) and Gramineae (Cymbopogon caesius) and their major monoterpenoidal constituents, linalool, eugenol, menthol, cineole and geraniol was determined against second‐stage juveniles of seed‐gall nematode (Anguina tritici), citrus nematode (Tylenchulus semipenetrans), root‐knot nematode (Meloidogyne javanica) and pigeon‐pea cyst‐nematode (Heterodera cajani). The essential oil of E. caryophyllata and its major constituent eugenol, as well as linalool and geraniol, exhibited non‐specific activity against all the four nematodes tested.