bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photodegradation of the pyrethroid insecticide fenpropathrin in water, on soil and on plant foliage
Authors: Takahashi Naohiro , Mikami Nobuyoshi , Yamada Hirohiko , Miyamoto Junshi 
Published: November 2006

AbstractThe photodegradation of fenpropathrin [(RS)‐α‐cyano‐3‐phenoxybenzyl 2,2,3,3‐tetramethylcyclopropanecarboxylate] (I), in water, on soil and on plant foliage, was investigated using 14C‐preparations labelled separately at the cyano group, cyclopropyl‐C1 or in the benzyl ring. On exposure to sunlight, I was photodecomposed with initial half‐lives of >6 weeks in distilled water, 6.0 weeks in humic acid aqueous solution, 2.7 weeks in river water, 1.6 weeks in sea water and 0.5 of a day in 2% aqueous acetone. A triplet photosensitiser, acetone, together with naturally occurring substances in river and sea water, including humic acid, enhanced the photodegradation of I. On three kinds of soil, I was rapidly photodegraded with initial half‐lives of 1–5 days, whereas it was fairly photostable on a mandarin orange leaf. The photoreactions involved were: decarboxylation, hydration of the cyano group to carboxamide, cleavage of the ester or the diphenyl ether linkage, hydrolysis of the carboxamide group to carboxyl, and hydroxylation at either or both of the gem dimethyl groups. The predominant reactions in water were decarboxylation, ester bond cleavage and photo‐induced evolution of [14C] carbon dioxide from the [14C] cyano label; on soil, hydration or ester bond cleavage predominated. The hydration was also of importance in river and sea water. Decarboxylation did not occur on soil and plant foliage.
Pirimiphos‐methyl applied to spanish citrus trees: Residue decay and final residue levels at harvest time in precocious fruits
Authors: Sendra José M. , Escamilla Juan C. , Santaballa Ernesto , Cuñat Pascual 
Published: November 2006

AbstractPirimiphos‐methyl [O‐(2‐diethylamino‐6‐methylpyrimidin‐4‐yl) O,O‐dimethyl phosphorothioate], the active ingredient in ‘Actellic 50E’ (ICI PLC, Plant Protection Division) insecticide formulation, was field‐applied at a rate of 7.5 kg a.i. 6000 litres−1 ha−1 to Spanish mandarin, orange and lemon trees growing in the main production areas (provinces of Castellón, Valencia, Alicante and Murcia). Dissipation curves over a 28‐day post‐application period, as well as the final residue levels at the harvest‐time in precocious fruits, were determined in order to assist in the setting of legal fruit tolerances and harvest withholding periods. In all cases, residue decay could be fitted to two consecutive first‐order processes. Final residue levels at harvest‐time (the first fortnight of October) in precocious fruits, as a result of one, two or three sprays at the usual application dates (the first fortnight of June and/or September) were, respectively: for Clementina mandarins 0.05, 0.57 and 0.72; for Satsuma mandarins 0.09, 0.55 and 0.73; and for Navelina oranges 0.08, 0.25 and 0.46 mg of pirimiphos‐methyl kg−1. The data indicated that starting from the seventh post‐application day, pirimiphos‐methyl degraded much more slowly in lemons growing in Alicante than in those growing in Murcia. It was speculated that this difference could be due to variations between the local field climates, or to a severe water stress, suffered by the orchard in Murcia as the result of a lack of irrigation water.
Stability of cypermethrin and cyfluthrin on wheat in storage
Authors: Noble Robert M. , Hamilton Denis J. 
Published: November 2006

AbstractCypermethrin and cyfluthrin were applied to wheat, which was stored for 52 weeks at 25 or 35°C, and either 12 or 15% moisture content. Total residues and the proportions of the four pairs of enantiomers, cis I [(αR),(1R)‐cis + (αS),(1S)‐cis], cis II [(αR),(1S)‐cis + (αS),(1R)‐cis], trans III [(αR),(1R)‐trans + (αS),(1S)‐trans], and trans IV [(αR),(1S)‐trans + (αS),(1R)‐trans] for each pyrethroid were determined at five intervals during storage. For all storage conditions, the cis I isomers were the most stable, and the trans IV isomers were the least stable. Calculated half‐lives (weeks) for the pairs of enantiomers at 25°C (12% moisture) and 35°C (15% moisture) were: cypermethrin, cis I, 252, 62 and trans IV 66, 27; cyfluthrin, cis I, 114, 52 and trans IV 42, 23. The results suggested that one of the enantiomers of the cypermethrin trans IV pair was degraded faster than the other.
Phosphonic analogues of morphactins. Part V: Peptides containing 9‐aminofluoren‐9‐ylphosphine oxides
Authors: Kafarski Pawel , Lejczak Barbara , Gancarz Roman , Jaskulska Elżbieta , Mastalerz Przemyslaw , Wieczorek Jan Sylwester , Zbyryt Iwona 
Published: November 2006

AbstractDi‐ and tripeptides containingP‐terminal 9‐aminofluoren‐9‐ylphosphine oxides were synthesised and evaluated for herbicidal activity usingSpirodela oligorriza(Kurz.) Hegelm. The glycylglycyl and threonyl peptides showed high activity as measured by the reduction of dry matter.
The estimation of residue levels of promacyl and its metabolites in beef tissue and fat by high‐performance liquid chromatography with electrochemical detection
Authors: Clegg Donald E. , Roberts Graham S. , Rzecki George 
Published: November 2006

AbstractA method is described for the estimation of residues of the carbamate insecticide promacyl [5‐methyl‐m‐cumenyl butyryl(methyl)carbamate] and its metabolites that are hydrolysable to isothymol (m‐cymen‐5‐ol), using high‐performance liquid chromatography with electrochemical detection to determine the isothymol. Clean‐up of samples relied on the steam volatility of phenols. Recoveries at the 0.1 mg kg−1 level varied from 72–88% for fat tissue and 81–91% for liver. The limits of detection were found to be 0.01 mg kg−1 for and 0.02 mg kg−1 for liver. A comparative study of the chromatography of sample extracts using both ultraviolet detection and electrochemical detection showed a substantial decrease in the level of interfering co‐eluates in the latter method. A field trial, involving a single spray application of the formulated acaricide on milking cattle, revealed residues in the butter fat comparable with those found in a previous investigation.
The resistance to eighteen toxicants of a strain of Musca domestica L. collected from a farm in England
Authors: Chapman Paul A. 
Published: November 2006

AbstractA sample of houseflies initially collected from a pig farm and found to be resistant to bendiocarb, DDT, gamma‐HCH, pyrethrins + piperonyl butoxide (PB), tetrachlorvinphos and trichlorfon, was tested for resistance to knockdown by other toxicants. At the KD50 response level, resistance factors were obtained for: permethrin (× 141), deltamethrin (×96), bioresmethrin + PB (×37), resmethrin + PB (×33), fenitrothion (×94), bromophos (×58), iodofenphos (×42), pirimiphos‐methyl (×30), dichlorvos (×22), dimethoate (×9), diazinon (×8), methomyl (×4) and methomyl + PB (×4). The slopes of the dose–response lines were lower for the farm strain than for a susceptible strain. This resulted in an increase of resistance factors at the KD95 level by an average of × 1.6. The houseflies on the farm could not be controlled using space sprays of pyrethrins + PB, although resistance to this toxicant was only ×12. However, control was achieved with a methomyl bait.
Analysis and dissipation of dislodgable residues of acephate, dimethoate and formetanate hydrochloride on citrus foliage
Authors: Hadjidemetriou Demetrios G. , Iwata Yutaka , Gunther Francis A. 
Published: November 2006

AbstractDislodgable residues of acephate and its hydrolysis product methamidophos, dimethoate and its oxygen analogue omethoate (dimethoxon), and formetanate hydrochloride on citrus foliage were determined by gas–liquid chromatography. The use of 5% OV‐101 coated on a Carbowax 20M surface‐modified support (Ultra‐Bond 20M) allowed the reproducible analysis of dimethoate and omethoate residues. Formetanate hydrochloride residues were analysed as the free base, without preparation of a derivative, on a column packed with 5% Apiezon N coated on 80–100 mesh Ultra‐Bond 20M. The dissipation of the residues of the three pesticides applied to citrus trees was studied. Acephate and formetanate hydrochloride dissipation curves followed first‐order kinetics; dimethoate residues were best characterised by two first‐order kinetic processes. The half‐life values were 8.2 days for acephate, undeterminably long for formetanate hydrochloride, and 2.2 days (the 1–10 days portion) and 7.0 days (the 10–49 days portion) for dimethoate.
Interaction of formamidines with octopamine‐, dopamine‐and 5‐hydroxytryptamine‐sensitive adenylate cyclase in the nerve cord of Periplaneta americana
Authors: Downer Roger G. H. , Gole John W. D. , Orr Gregory L. 
Published: November 2006

AbstractThe interaction of chlordimeform, N1‐demethylchlordimeform [N2‐(4‐chloro‐o‐tolyl)‐N1‐methylformamidine], BTS‐27271 [N1‐methyl‐N2‐(2,4‐xylyl)formamidine, the 2,4‐xylyl analogue of N1‐demethylformamidine], and amitraz with octopamine‐, dopamine‐, and 5‐hydroxytryptamine‐mediated enhancement of cyclic‐AMP production was investigated in nerve cord homogenates of the American cockroach Periplaneta americana. N1‐Demethylchlordimeform, BTS‐27271 and amitraz simulated the actions of the monoamines in enhancing cyclic‐AMP production, whereas chlordimeform showed no such agonism. Additivity studies indicated that these formamidine derivatives were interacting with dopamine‐ and 5‐hydroxytryptamine‐sensitive sites, in addition to their known interaction with octopamine‐sensitive adenylate cyclase. N1‐Demethylchlordimeform (Ki= 0.2μM) and amitraz (Ki=0.5μM) inhibited the dopamine‐mediated response, but only N1‐demethylchlordimeform (Ki=2μM) effected appreciable inhibition of the octopamine‐response. Pharmacological characterisation of the formamidineinduced elevation of cyclic‐AMP production indicated that the agonistic effects of formamidines are expressed primarily through the octopamine‐sensitive adenylate cyclase, rather than the dopamine‐ or 5‐hydroxytryptamine‐sensitive sites. The results are discussed in the light of the proposal that the behavioural changes, associated with formamidine poisoning, reflect the cumulative effects of octopamine‐agonism, and antagonism of the dopamine‐ and 5‐hydroxytryptaminemediated processes.
The actions of formamidine pesticides on identified central neurones of Helix aspersa
Authors: Bokisch Anita J. , Cox Rosalind T. L. , Walker Robert J. 
Published: November 2006

AbstractMembrane potential and voltage clamp measurements of the responses to octopamine, dopamine, O‐acetylcholine, and the formamidine derivatives chlordimeform (CDM) and N1‐demethylchlordimeform (DCDM) have been made on identified central neurones of Helix aspersa. DCDM and CDM were agonists on both the inhibitory and excitatory octopamine receptors on these neurones but were less potent than octopamine. The direct inhibitory effect of DCDM was antagonised by both phentolamine and cyproheptadine. DCDM was also found to antagonise the effects of octopamine, dopamine and O‐acetylcholine on these neurones. The pA2 values for DCDM against dopamine and O‐acetylcholine were 5.2 (±0.1) and 5.35 (±0.15), respectively. The pA2 value=log[DR‐(1/I)], where I is the concentration of the antagonist, and DR=dose ratio =A2/A1; A1 is the dose of agonist required to produce 50% of the maximum response, and A2 is the dose of agonist needed to produce the same degree of response in the presence of the antagonist. It is concluded that DCDM and CDM act specifically on the octopamine receptors of H. aspersa central neurones, both as agonists and antagonists. The antagonist effect of DCDM against dopamine receptors is probably non‐specific.
Effects of 22,23‐dihydroavermectin B1a on locust (Schistocerca gregaria) muscles may involve several sites of action
Authors: Scott Roderick H. , Duce Ian R. 
Published: November 2006

AbstractIbotenic acid [2‐(3‐hydroxyisoxazol‐5‐yl)glycine] induced a dose‐dependent increase in chloride ion conductance in locust muscle fibres which was not sensitive to 4‐aminobutyric acid (GABA). This ibotenate response became rapidly desensitised and appeared to be due to activation of extrasynaptic glutamate H receptors. 22‐23‐Dihydroavermectin B1a (DHAVM) (500 pg to 1 μg ml−1) induced irreversible increases in permeability to the chloride ion and abolished ibotenate responses. DHAVM responses were not altered when glutamate H receptors were desensitised by glutamate (1 mM) or ibotenate (100 μM). Irreversible changes in input conductance caused by DHAVM were not affected by penicillin G (1 mM) or bicuculline (1 mM), but picrotoxin (1 mM) and zinc chloride reduced DHAVM responses by 23.7 and 52.6%, respectively. It is concluded that DHAVM has a number of sites of action on locust muscle that include effects on the glutamate H receptor–chloride ion channel complex, in addition to effects on the GABA receptor–chloride ion channel previously described.
Recent studies on the effects of DDT and pyrethroid insecticides on nervous activity in cockroaches
Authors: Pichon Yves , Guillet Jean Claude , Heilig Ulf , Pelhate Marcel 
Published: November 2006

AbstractA summary is given of the results of three sets of electrophysiological experiments on the American cockroach (Periplaneta americana). The effects of DDT and S‐bioallethrin [bioallethrin (S)‐cyclopentenyl isomer] on single giant axons were studied using the voltage‐clamp technique. Whereas both molecules induced long tails of inward (sodium ion) current, the voltage and time‐dependency of these tails differed. With DDT, the tail was proportional to the activation of the peak current and decreased with the duration of the pulse, suggesting that the molecules were bound to open sodium channels and delayed their closing. With S‐bioallethrin, the voltage dependency of the tail was different from that of the peak current, and the tail current increased exponentially with the duration of the depolarisation, suggesting that the pyrethroid insecticide modified resting (or silent) sodium channels into slowly activating channels. Modified action potentials, mimicking those produced by the two molecules, were computed on the basis of these results. Deltamethrin, one of the most potent pyrethroid insecticides, was applied topically on a leg mechanoreceptor and was found to have little effect on the local ‘receptor potential’ but to inhibit action potential production. The effects of topical applications of deltamethrin on the dorsal part of the abdomen, on nervous activity in the abdominal connectives, were studied under different experimental conditions. The results suggest that the insecticide molecules diffused rapidly through the cuticle, were concentrated in the haemolymph, and eventually reached the central nervous system, where they inhibited nerve activity.
Effects of topical application of three pyrethroid insecticides on spontaneous activity in sensory nerves of Periplaneta americana and Blabera craniifer
Authors: Heilig Ulf , Pichon Yves 
Published: November 2006

AbstractElectrophysiological techniques were used to analyse the effects, on the activity in the sensory nerves of Periplaneta americana and Blabera craniifer, after topical applications of three different pyrethroid insecticides: deltamethrin, (1R)‐tetramethrin, and 5‐benzyl‐3‐furylmethyl (E)‐(1R)‐cis‐2,2‐dimethyl‐3‐(2‐oxothiolan‐3‐ylidenemethyl)cyclopropanecarboxylate (RU‐15525; ‘Kadethrin’). The insecticides were applied: (a) to the cercus, and the activity was recorded on the cercal nerve and on the central nervous connectives; or (b) to the last segments of the metathoracic leg, and the corresponding activity was recorded on the crural nerve. In both cases, several categories of receptor were affected but the major part of the recorded activity came from the mechanoreceptors, the functional properties of which were monitored throughout the experiments. In most cases, topical application of small amounts of pyrethroid were found to induce an increase in the spontaneous activity, followed by decrease in excitability. Characteristic differences were, however, found between the three compounds and the effects were concentration‐ and solvent‐dependent. The results were consistent with those obtained from experiments on the sense organs of vertebrates but did not support the idea that the effectiveness of pyrethroid insecticides with an α‐cyanobenzyl group, compared with those without an α‐cyanobenzyl group, originates from a greater effect on the peripheral sensory receptors.
Modelling the economics of controlling Avena fatua in winter wheat
Authors: Cousens Roger , Doyle Christopher J. , Wilson Bernard J. , Cussans George W. 
Published: November 2006

AbstractA simple mathematical model of the life‐cycle of Avena fatua L. is described and used to consider the financial consequences to the farmer of controlling A. fatua infestations in winter wheat. The likely economic benefits of applying herbicides in different cultivation regimes are investigated. The sensitivity of the model to variations in herbicide performance, straw burning, initial weed infestation and the value of the wheat crop is tested. The model predicts that the highest long‐term benefits will be obtained when a herbicide is applied every time wild oats exceed a density of between 2 and 3 seedlings m−2. Whether or not this results in a significant financial saving over spraying every year depends on the initial level of infestation and on the cultivation method. Whether straw is burnt or not is likely to be of little economic significance.
The effect of the annual use of some pesticides on soil microorganisms, pesticide residues in soil and carrot yields
Authors: Heinonen‐Tanski Helvi , Siltanen Hilkka , Kilpi Sisko , Simojoki Paavo , Rosenberg Christina , Mäkinen Seppo 
Published: November 2006

AbstractThe study deals with the effect of common, annually‐used pesticides on soil microorganisms, pesticide residues in soil, and carrot (Daucus carota) yields in Central Finland. Linuron residues in carrot roots were also analysed. Thiram+lindane and dimethoate were applied from 1973–1981 at the commercially recommended doses on experimental plots of carrots, linuron was applied at twice the recommended rate from 1973–1979 and at the normal rate thereafter and in addition TCA was applied in 1978. Maleic hydrazide was used in the years 1973–1976, and glyphosate after 1977. The numbers of different soil microorganisms, their activities and the pesticide residues were studied from autumn 1978 to 1981. The pesticide treatments reduced the growth of soil algae but increased the total number of microorganisms and the number of aerobic spore‐forming bacteria. Linuron residues in the soil were 0.9–2.8 mg kg−1 in the growing season and 1.2–1.7 mg kg−1 in the autumn, 3 months after application. The residues of glyphosate in the soil were 0.7 mg kg−1 in the autumn, 41 days after the treatment, and had declined to a level of about 0.2 mg kg−1 by the following summer. In the pesticide‐treated plots the carrot yield was only 20–60% of the yield in the hand‐weeded plots. The herbicide programme controlled most of the annual weeds but not couchgrass Elymus repens and milk sow‐thistle Sonchus arvensis.
Factors affecting the biological efficiency of small pesticide droplets against Tetranychus urticae eggs
Authors: Munthali David C. , Wyatt Ian J. 
Published: November 2006

AbstractUsing monosized oil‐based droplets of dicofol against Tetranychus urticae eggs on 1 cm2 discs of bean leaf, the effects of varying droplet diameter (18–146 μm) and concentration of active ingredient (0.5–40 g litre−1) on egg mortality were investigated. A positive curvilinear relationship was found between the spacing of droplets required to produce 50% kill (LS50) and the original diameter of the droplet, D, such that:

where b varied from 0.65 to 1.44 and bore a U‐shaped relationship to concentration. Thus, there was an optimum concentration of about 10 g litre−1, with control efficiency reducing as much as nine times at the extreme concentrations, and even more from the smallest to the largest droplets. The theoretical, practical and economic implications are discussed.
The significance of response time in the detection and measurement of fumigant resistance in insects with special reference to phosphine
Authors: Winks Robert G. 
Published: November 2006

AbstractThe significance of the time of assessment in measurements of fumigant toxicity was examined, using the response of adults of Tribolium castaneum to phosphine. When assessments were made before end‐point was reached, large differences were obtained in mortality levels and in parameters of probit lines fitted to the data. These differences reflected the concentration‐ and dosage‐dependent nature of the speed of action, observed previously with this fumigant. The implications of this in the measurement of resistance were examined. In this instance, comparisons at the same concentration were not greatly affected if seven days or longer had elapsed after exposure. However, it was clear that if different concentrations were used for the susceptible strain and the resistant strain, comparisons made before the end‐point for acute mortality response was reached could be grossly misleading. This is further discussed in the context of some recent reports of phosphine resistance. The results of this study are of significance in assessing the effect of any poison, drug or other stimulus applied to a group of organisms when the time to respond is likely to vary among individuals.
Ultrastructural changes occurring in wheat leaves following triadimefon treatment
Authors: Pring Richard J. 
Published: November 2006

AbstractChanges occurred in leaf cells following treatment of glasshouse grown wheat seedlings with triadimefon by foliar application, root drench and vapour action. The effects were limited to cells adjacent to stomata, and included damage to the tonoplast and plasmalemma followed by breakdown of chloroplasts. These effects probably resulted from changes in membrane sterols induced by triadimefon treatment. They were severe local reactions, distinct from modification of gibberellin biosynthesis.
Stereochemistry of fluazifop‐butyl transformations in soil
Authors: Bewick David W. 
Published: November 2006

AbstractFluazifop‐butyl was incubated with two soils under aerobic conditions at 20°C. Hydrolysis of the racemic herbicidal ester yielded a residue of the corresponding carboxylic acid, fluazifop, in which the R‐enantiomer predominated. Further studies involving the treatment of soil with the separate enantiomers of fluazifop‐butyl showed that the two enantiomers were each hydrolysed with retention of their optical configuration. However, the hydrolysis product with the S‐configuration was inverted (50% inversion in 1‐2 days) to yield, ultimately, a residue of the R‐enantiomer with a high optical purity.
Hydrolysis of cyanazine in aqueous solutions of weak acids
Authors: Grayson B. Terence 
Published: November 2006

AbstractIn the presence of mineral acids or bases the cyano group is the primary point of hydrolysis of cyanazine. However, in solutions of weak acids, carboxylic acids or phenols, the chloro group becomes labile even in essentially neutral solutions. The rates of this catalysed hydrolysis reaction have been determined with a number of carboxylic acids and 2,4‐dinitrophenol. The calculated rates of catalysis follow the Brönsted relationship with a value of ∼0.7. The reaction with 2,4‐dinitrophenol produces an isolatable ether intermediate. Comparison of the rates of hydrolysis catalysed by crotonic acid in deuterium oxide and in water suggests that the mechanism may be of the type specific acid/general base (or nucleophilic) catalysis rather than general acid catalysis.