bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissipation of residues of MCPA and cyanazine in three forage grasses following post‐emergence application as a mixture in the establishment year
Authors: Cessna Allan J. , Darwent A. Lloyd , Moyer James R. , Cole Dan E. 
Published: November 2006

AbstractThe dissipation of MCPA and cyanazine in smooth bromebrass (Bromus inermis Leyss.), Russian wild ryegrass (Elymus junceus Ficsch.) and intermediate wheatgrass (Agropyron intermedium) (Host) Beauv.) grown at three sites in western Canada was monitored for an eight‐week period following post‐emergence application of the herbicides as a mixture at 0.56 + 0.28 kg ha −1. The grasses were in the two‐ to six‐leaf stage at the time of application. MCPA, as its methyl ester, was detected using electrolytic conductivity detection whereas N‐specific alkali‐ionization detection was used for cyanazine. Foliar MCPA residues decreased more rapidly than those of cyanazine. At 56 days after application, MCPA residues were non‐detectable in all three grass species at all sites. Corresponding residues of cyanazine were of the order of the limit of quantification (0.02 mg kg −1 or less.
Synthesis and acaricidal activity of 3‐aryl‐5‐arylmethyl‐1, 3,4‐oxa(thia)diazol‐2(3h)‐ones
Authors: Bettarini Franco , Capuzzi Luigi , La Porta Piero , Massimini Sergio , Meazza Giovanni , Reggiori Franca 
Published: November 2006

AbstractA series of new 1,3, 4‐oxa(thia)diazol‐2(3H)‐ones were synthesized and tested as acaricides. High activities against eggs of Tetranychus urticae (Koch) were found for derivatives bearing an ortho‐halo‐substituted phenyl group in position 3, and a benzyl group para‐substituted by a branched C3‐C6 alkoxy group in position 5 of the hetero‐ring. The best compounds attained the miticidal potency of clofentezine.
Effect of azadirachtin‐derived decalin (perhydronaphthalene) and dihydrofuranacetal (furo[2, 3‐fo]pyran) fragments on the feeding behaviour of Spodoptera littoralis
Authors: Blaney Wally M. , Simmonds Monique S. J. , Ley Steven V. , Anderson James C. , Smith Stephen C. , Wood Anthony 
Published: November 2006

AbstractDecalin and dihydrofuranacetal fragments related to those in azadirachtin exhibited antifeedant activity against larvae of the African leaf‐worm Spodoptera littoralis. Boisd. All the decalin fragments tested were methoxy (C11) derivatives of azadirachtin. The most active decalin fragment had a ketone substitution at C7. Overall, the compounds were more active when tested in combinations of one decalin fragment and one dihydrofuranacetal fragment than when tested singly. Although some of these combinations did show significant levels of antifeedant activity, sometimes coupled with a synergistic effect, they were not as active as either azadirachtin or dihydroazadirachtin.
The metabolism of tralkoxydim in field‐grown spring wheat and maize plant cell suspension culture
Authors: Hadfield Stephen T. , Wilson Anahita , Kuet Sui F. , Mason Robert 
Published: November 2006

AbstractAbstract: The metabolism of tralkoxydim was studied in wheat grown under field conditions and treated at a rate equivalent to 345 g a.i. ha −1. Maize plant cell suspension culture was used as a means of indicating the nature of the primary metabolic process, and also as a source of material for structural elucidation. The principal metabolic process in wheat involved hydroxylation of the p‐methyl function of the aromatic ring. This occurred in conjunction with a range of possible transformations of the (ethoxyimino)propyl function, or oxidative cleavage of the cyclohexanedione ring. All the initial metabolic products were amenable to further conjugation with a range of endogenous sugars.
Photolysis of pirimicarb in water under natural and simulated sunlight conditions
Authors: Romero Esperanza , Schmitt Phillipe , Mansour Mohamed 
Published: November 2006

AbstractThe photostability of pirimicarb, (2‐dimethylamino‐5,6‐dimethylpyrimidin‐4‐yl dimethylcarbamate) in aqueous media, under natural and artificial sunlight irradiation conditions, is reported. The pH of the irradiated solutions remained constant during degradation time. The photodegradation mechanism seemed to be similar under both conditions, but the half‐life was found to be about three times longer under natural than under artificial conditions. Four main photo‐products (1, 2, 3 and 4) were isolated and identified by spectroscopic methods. It is proposed that a common photodegradation pathway exists for pirimicarb under both irradiation conditions. The results obtained from the photodegradation of pirimicarb and of its four main products isolated on solid phase permit the construction of a possible photodegradation pathway. Photoproduct 4 (2‐methyl‐formylamino‐5,6‐dimethyl‐4‐hydroxypyrimidine) is here described for the first time.
Influence of carbon and nitrogen application on the mineralization of atrazine and its metabolites in soil
Authors: Assaf Nasser A. , Turco Ronald F. 
Published: November 2006

AbstractIt has been proposed that levels of carbon and nitrogen in soil affect the rate at which triazine herbicides degrade. The present study was designed to investigate the effects of varying the levels of initial soil carbon and nitrogen as well as the effects of a later carbon addition on the mineralization of atrazine and its metabolites in soil. Atrazine degradation in soils amended with carbon as mannitol, and with nitrogen as urea, at levels of 10, 30, 50, or 80 mg kg−1 mannitol, urea, or mannitol and urea was similar to degradation in unamended soils. Only 39% of applied atrazine was mineralized after 326 days regardless of the initial carbon or nitrogen treatment. In contrast, a second mannitol amendment of 1 g kg−1 soil at day 140 increased [14C]carbon dioxide evolution by an additional 17% as a result of enhancing the mineralization rate of the atrazine metabolites. This conclusion is supported by our finding that periodic extraction of the soil with methanol followed by quantification on HPLC showed complete dissipation of the parent atrazine in 120 days. The metabolites hydroxyatrazine (HA), deisopropylatrazine (DIA), deethylatrazine (DEA), and diaminochlorotriazine (DACT) began to appear in the methanol extract 10 days following atrazine application. The greatest concentrations of HA, DEA, DIA. and DACT in the methanol extracts were 19, 12.4, 10.1, and 6.7% of applied atrazine, respectively. These concentrations were observed at day 95 except for DEA where the concentration continued to increase until day 142. A second soil extraction with hydrochloric acid (1m) + methanol (20 + 80 by volume) recovered additional HA, deethylhydroxyatrazine (DEHA), deisopropylhydroxyatrazine (DIHA), and DACT. When the extraction data were combined, 31.9, 12.4, 10.1. 10.2, 12.0 and 7.8% of applied atrazine was recovered as HA, DEA, DIA, DEHA. DIHA, and DACT, respectively. Combustion of the extracted soil showed 20% of the applied atrazine remained as soil‐bound residues after 326 days.
Cuticular sorption and desorption of a nonionic diethylene glycol monooleate surfactant
Authors: Tan Siyuan , Crabtree Garvin D. 
Published: November 2006

AbstractSorption and desorption of ‘Pegosperse’ 100‐O(PEG 100‐O; diethylene glycol monooleate, containing 15% diester) surfactant by unaltered (CM) and dewaxed (DCM) adaxial cuticle membranes isolated from apple (Malus pumila M.) leaves were studied. The aim of this study was to understand interactions between surfactants and cuticles. Enzymatically isolated cuticles were soaked in buffer or PEG 100‐O solution (pH 7–0). and the weight changes of cuticles were measured to determine the amount of surfactant sorbed or desorbed by the cuticles. For very low surfactant concentrations, sorption was measured by changes in the surface tension of the solutions. PEG 100‐O sorption by both the CMs and the DCMs occurred mainly in the first three hours and was concentration‐dependent. The DCMs always sorbed more surfactant than the CMs. Desorption of PEG 100‐O from both CMs and DCMs was rapid in the first few hours and then decreased to a relatively low rate until the surfactant was totally desorbed from the cuticles after about two months. The sorption and complete desorption of the surfactant by both CMs and DCMs show that PEG 100‐O interacts with both cutins and waxes of the cuticles and the interactions are reversible.
Solid‐phase thermal decomposition of benomyl
Authors: Bartolomei Monica , Cignitti Maurizio , Cotta‐Ramusino Marina , Iela Maria T. , Soccorsi Laura 
Published: November 2006

AbstractSolid‐phase decomposition of benomyl has been investigated by thermo‐gravimetric analysis; the degradation process (heating rate of 1°C min−1 under nitrogen flux) starts at c. 65°C. Semi‐empirical quantum mechanical methods have been used to characterize the benomyl molecule and to obtain information on a possible degradation mechanism.
Mechanisms of dicarboximide ring opening in aqueous media: Procymidone, vinclozolin and chlozolinate
Authors: Villedieu Jean C. , Calmon Michelle , Calmon Jean P. 
Published: November 2006

AbstractThe hydrolysis kinetics of the dicarboximide fungicides procymidone, vinclozolin and chlozolinate in neutral and alkaline solutions of pH 60 to 13·7 at 25°C have been determined conjointly by ultraviolet spectrophotometry and by high performance liquid chromatography. Under alkaline conditions, the fungicides undergo attack by the hydroxide ion on a specific carbonyl group and the rate of hydrolysis increases proportionally to the hydroxide ion concentration. Procymidone gives quantitatively and irreversibly 2‐(3,5‐dichlorophenylcarba‐moyl)‐l,2‐dimethylcyclopropanecarboxylate. The reaction is not subject to general base catalysis and experimental data are in agreement with a rate‐determining attack by the hydroxide ion. After a rapid hydrolytic loss of the ethoxycarbonyl substituent from chlozolinate, the dicarboximide ring cleavage of the two other fungicides leads, by mechanisms which differ with respect to the type of base catalysis and the rate‐determining step, to the corresponding anilides, producing as intermediates the carbamic acids, which undergo loss of carbon dioxide. The hydrolysis of vinclozolin and chlozolinate yields, respectively, N‐(3,5‐dichloro‐phenyt)‐2‐hydroxy‐2‐methylbut‐3‐enanilide and N‐(3,5‐dichlorophenyl)‐2‐hydroxy‐propanilide.
Metabolism of amitrole in apple: III. Model systems
Authors: Schneider Bernd , Stock Manfred , Bohm Hartmut , Schneider Gernot , Schütte Horst‐Robert , Schreiber Klaus , Brauner Angela , Köster Johannes , Kaußmann Ernst U. 
Published: November 2006

AbstractExcised shoots from apple trees and cell suspension cultures were used as model systems to study the metabolism of [3,5‐14C]amitrole in Malus domestica Borkh. Significant differences in the metabolism of the compound applied were observed with excised shoots, cultured cells and whole apple trees. The major metabolite in excised shoots was aminotriazolylalanine which occurred both in the free form and as conjugates. The major metabolite from whole plants. triazolylalanine, was detected in shoots in minor amounts only. In cell suspension cultures, the type of metabolism strongly depended on the concentration of amitrole when initially applied. At 10 −3 m or lower, mainly aminotriazolylalanine was formed. Depending on the concentration of the active ingredient, this metabolite predominantly occurred in free form or as glycosides. At concentrations above 5 × 10−4 M a new metabolite, 3,5‐dihydroxytriazole, was detected which was the only metabolite found at 5 × 10−3M. Significant amounts of nonmetabolized amitrole remained in the medium.
2‐Trichloromethylbenzimidazole, a new selective chromogenic reagent for detection of some heteroaromatic pesticides on thin‐layer chromatographic plates
Authors: Konopski Leszek 
Published: November 2006

AbstractA highly selective method for the detection of several pesticides containing a heteroaromatic ring in the molecule (e.g. nicotine, pyrifenox or prochloraz) on thin‐layer chromatographic (TLC) plates is described. The necessary detection condition is the presence in the ring of at least one tertiary nitrogen atom without substitutents on the two adjacent carbon atoms and, in the case of azoles, the protection of a secondary NH group by an alkyl or acyl group. The detection is realized by spraying the developed chromatogram with an acetone solution of 2‐trichloromethylbenzimidazole and subsequently heating at 100‐150°C in a drier. The detection limit is 20 ng to 10 μg depending on the detected compound. Some pesticide formulations may be analyzed using this method.
Differential effects of the acylurea insect growth regulator teflubenzuron on the adults of two endolarval parasitoids of Plutella xylostella, Cotesia plutellae and Diadegma semiclausum
Authors: Furlong Michael J. , Verkerk Robert H. J. , Wright Denis J. 
Published: November 2006

AbstractThe acylurea chitin synthesis inhibitor, teflubenzuron (‘Nomolt’® SC) showed no apparent activity against adult males of Diadegma semiclausum Hellén or Cotesia plutellae Kurdj. when applied to foliage at a rate ( = 50 g a.i. ha−1) approximating to 2 × field usage. In contrast, the pyrethroid cypermethrin (‘Cymbush’® EC) showed appreciable foliar activity (at rates = 10–50 ga.i. ha−1) to D. semiclausum but showed low activity against C. plutellae. When single adult female D. semiclausum were pre‐treated with teflubenzuron (= 50 g a.i. ha−1) and then exposed to 5. 10. 25, 50 or 100 second‐instar host larvae, the number of purasitoid cocoons formed was significantly reduced compared with controls except at the lowest host density (P 0‐05). However, there was no evidence that teflubenzuron had a host density‐dependent effect on parasitism by D. semiclausum. Teflubenzuron had no significant effect on host parasitism in an equivalent experiment with C. plutellae (P > 0‐05) except at the median host density. When batches of ten host larvae were introduced at hourly intervals to female D. semiclausum pre‐treated with teflubenzuron (= 50 g a.i. ha−1), the number of cocoons formed in the first two batches was not significantly different from untreated controls (P > 0‐05), whereas teflubenzuron significantly reduced the number of cocoons in the next three batches of host larvae (P < 0‐05). This suggests that teflubenzuron may affect chitin synthesis in developing eggs within female D. semiclausum but has little or no effect on pre‐formed eggs which are more likely to be oviposited first. Teflubenzuron had no significant (P > 0‐05) effect on parasitism by C. plutellae when presented with batches of host larvae. When female D. semiclausum and C. plutellae were placed in the same host arena, the former showed a 3‐fold greater rate of parasitism. Pre‐treatment with teflubenzuron significantly reduced parasitism by D. semiclausum (P > 0‐05) but had no significant effect with C. plutellae (P > 0‐05) although the latter species failed to exploit the reduction in parasitism by D. semiclausum. The differential response of D. semiclausum and C. plutellae to insecticides is discussed in relation to the relative rates of establishment of these species in Malaysia.
Chemical versus microbial degradation of cyanazine and atrazine in soils
Authors: Blumhorst Michael R. , Weber Jerome B. 
Published: November 2006

AbstractA laboratory study was performed to investigate the relationship between chemical (non‐biological) and microbial degradation of cyanazine and atrazine in soils ranging in pH from 5.3 to 8.1. Atrazine degradation was dominated by chemical processes in both a moderately acidic and a neutral pH soil, but showed a significant microbial involvement in the neutral pH soil. The primary cyanazine degradative mechanism was dependent on soil properties. Cyanazine was short‐lived in neutral to slightly basic soils, due to rapid microbial degradation. Cyanazine amide and cyanazine acid were the major metabolites formed. In a moderately acidic soil, microbial degradation was slowed and chemical processes were the primary means of cyanazine degradation.
Extended summary joint BCPC/SCI symposium seed treatment: Progress and prospects.
Authors: Brent Keith J. 
Published: November 2006

AbstractThe following extended summary represents an overview of the topics and points of interest raised at the above meeting organised by T. J. Martin, British Crop Protection Council, and held at the University of Kent, Canterbury, UK on 5–7 January 1994. The summary is a personal and highly selective appraisal of the meeting and any views expressed do not necessarily reflect those of the Editorial Board of Pesticide Science.
N‐(pyrid‐3‐yl)thioureas and derivatives as acaricides. I. Synthesis and biological properties
Authors: Pascual Alfons , Rindlisbacher Alfred 
Published: November 2006

AbstractIn the course of optimization studies around diafenthiuron, the central aromatic nucleus linked directly to the thiourea unit was replaced by a pyridine moiety. A series of N‐(pyrid‐3‐yl)thioureas, ‐isothioureas and ‐carbodiimides was synthesised and evaluated for acaricidal activity. The synthetic methodology used and the screening results against some spider mites (Tetranychus spp. and Panonychus ssp.) are discussed.
Esterase isozymes in Lygus hesperus: Characterization and relationship with organophosphate resistance
Authors: Xu Gang , Brindley William A. 
Published: November 2006

AbstractEsterases of Lygus hesperus Knight from five field and one laboratory populations were separated by non‐denaturing polyacrylamide gel electrophoresis and were characterized for inhibition and substrate specificity. There were six zones of esterase activity toward naphthyl ester substrates. Significant inter‐ and intra‐populational polymorphisms were observed. All the isozymes were carbo‐xylesterases that were sensitive to inhibition by paraoxon and insensitive to eserine or EDTA (ethylenedinitrilotetraacetic acid). Carboxylesterases from L. hesperus more readily hydrolysed naphthyl esters with short side chains. Molecular weight estimation by non‐denaturing polyacrylamide gel electrophoresis revealed that Est‐1, the specific band of older females and eggs, contained two enzymes with relative molecular masses of 140000 and 112000. The four esterase allozymes in Est‐3 had an average relative molecular mass of approximately 106000. The frequency of one putative allozyme in Est‐3 was directly correlated with the LC50 values of trichlorfon (to which L. hesperus has become resistant). The developmental and distribution variability of the esterase isozymes are compared.
Association between elevated activity of aryl acylamidase and propanil resistance in Jungle‐rice, Echinochloa colona
Authors: Leah Jon M. , Caseley John C. , Riches Charles R. , Valverde Bernal 
Published: November 2006

AbstractAryl acylamidase (aryl‐acylamine amidohydrolase, EC 3.5.1.13) activity has been measured in crude extracts from leaves of propanil‐susceptible (S) and propanil‐resistant (R) biotypes of the grass weed. Echinochloa colona (L.) Link from Columbia. Both specific and total amidase activity increased with plant age up to 15 days (four‐leaf stage), then decreased beyond 20 days to about 50% of the maximum at 36 days in both R and S E. colona biotypes. Specific activity with propanil in the R biotype was about 80% of that obtained for rice (Oryza sativa L.), compared to 25% in the susceptible biotype. The specific activity of the propanil amidase was three‐fold higher in the R biotype than in the S. Partially purified amidase extracts from rice and both S and R biotypes of E. colona were compared biochemically. Both rice and E. colona amidases had a pH optimum of 7.5 and native relative molecular masses, estimated by gel filtration, of 179 000 and 181 000, respectively. Out of six substrates tested, three produced appreciable activity (propanil, 4‐chloroacetanilide and acetanilide) in both rice and E. colona. Michaelis constants showed that the rice amidase had a higher affinity for propanil (0.36 mM) than had the E. colona enzyme (1.1 mM). Carbamates and organo‐phosphorus pesticides were shown to inhibit amidase activity in partially purified rice and E. colona extracts. Additional preliminary data have implicated peroxidase in the next step of propanil metabolism in vitro. These data demonstrate that increased aryl acylamidase activity contributes to resistance to the herbicide propanil in E. colona weeds. Also, a biochemical comparison of purified aryl acylamidases from S and R biotypes of E. colona is presented for the first time.
A review of biochemical mechanisms of warfarin resistance in the house mouse
Authors: Macnicoll Alan D. 
Published: November 2006

AbstractThe biochemical mechanisms of warfarin resistance in the house mouse (Mus musculus L.) have not been fully investigated. In some populations of warfarin‐resistant mice there is a reduction in sensitivity of hepatic vitamin K‐epoxide reductase to inhibition by warfarin. This is similar to a proposed mechanism of anticoagulant resistance in the Norway rat (Rattus norvegicus Berk.). The same enzyme in other warfarin‐resistant populations is, however, sensitive to warfarin inhibition. Other studies have indicated that detoxification may play a role in conferring warfarin resistance in house mice.
Warfarin‐based rodenticides: Mode of action and mechanism of resistance
Authors: Thijssen Henk H. W. 
Published: November 2006

AbstractWarfarin and related substances have been in use as rodenticides for fifty years. They act by binding to the enzyme vitamin K 2,3‐epoxide reductase, thereby interrupting the cellular recycling of vitamin K. Vitamin K in its hydroquinone form is an essential cofactor for the synthesis of functional prothrombin and related blood‐clotting factors. The binding with the reductase is essentially irreversible, indicating these compounds have a prolonged half‐life in target tissues; 7–10 days for warfarin and congeners and over 100 days for the second generation rodenticides or ‘superwarfarins’ such as difenacoum, brodi‐facoum, and flocoumafen. Rat liver contains 1–2 nmole of enzyme per gram tissue which is a 4–5 fold overcapacity for maintaining effective vitamin K recycling. The use of warfarin as a rat poison has resulted in the natural selection of warfarin‐resistant rats. The resistance is inheritable. Two distinct warfarin resistance genotypes, Welsh and Scottish, have been identified, clearly differing in their biochemistry of vitamin K epoxide reductase. In the Welsh strain, resistance arises from an altered enzyme expressing reduced reactivity to warfarin, whereas the reductase from the Scottish strain is as sensitive as the normal enzyme, but the interaction with warfarin is now readily reversible. The altered enzyme leaves the Welsh rat in need of higher dietary vitamin K intake. The superwarfarins cope with the resistance by having their structures firmly bind with the altered enzymes. Reduced sensitivity to warfarin‐based rodenticides may also be pharmacokin‐etically based, arising from increased warfarin biotransformation. This mechanism may be responsible for resistance to some of the superwarfarins such as difenacoum. A third resistance mechanism may arise from an enhanced capacity to synthesize vitamin K from menadione, a commonly used additive in animal foods on farms. The choice of rodenticide in the case of warfarin resistance should be guided by the underlying mechanism of resistance.