bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential new targets for herbicides
Authors: Dodge Alan D. 
Published: November 2006

AbstractAll currently utilized herbicides have been identified by random screening and related compounds developed by subsequent imitative chemistry. Little success has as yet been achieved by rational design. Ideas for herbicide design are discussed in relationship to enzyme inhibition, enzyme regulation and the accumulation of toxic metabolites. A number of herbicides in current use function either by promoting the formation of toxic radicals or by inhibiting protective systems. There is scope for the development of protective enzyme inhibitors, as well as the modulation of other scavenging systems. Natural or synthetic photosensitizers as well as a number of allelopathic chemicals could be used as herbicides. Herbicide selectivity could be investigated by the selective inhibition of C4 photosynthesis enzymes, by a detailed examination of enzyme diversity, or by the modulation of mono‐oxygenase enzymes or glutathione conjugation.
Synergised cyfluthrin and cypermethrin as grain protectants on bulk wheat
Authors: Bengston Mervyn , Desmarchelier James M. , Hayward Breck , Henning Ronald , Moulden John H. , Noble Robert M. , Smith Graeme , Snelson Jack T. , Sticka Rex , Thomas David , Wallbank Barry E. , Webley David J. 
Published: November 2006

AbstractDuplicate field trials were carried out on bulk wheat in commercial silos in Queensland and New South Wales. Laboratory bioassays on samples of treated grain at intervals over 8 or 9 months storage using malathion‐resistant strains of insects established that treatments were generally effective. Cyfluthrin (2 mg kg−1) plus piperonyl butoxide (10 mg kg−1) and cypermethrin (4 mg kg−1) plus piperonyl butoxide (10 mg kg−1) completely controlled two strains of Sitophilus oryzae L. Control of a third strain by the cypermethrin combination was incomplete after 11/2 months and neither controlled a multi‐resistant laboratory strain. Both combinations were effective against Rhyzopertha dominica F., Tribolium castaneum Herbst and Ephestia cautella Walker. No natural infestation developed in the treated grain in any silo.Mean residues of cyfluthrin and cypermethrin after 9 months storage were 58% and 52% of the calculated application rates, respectively. Compared with overall concentrations in the wheat, residue levels were higher in bran and pollard and lower in white flour. During baking, residues decreased by up to 29%. Operators experienced respiratory irritation associated with exposure to both combinations and alternative formulations would be required for use of these materials in grain storage.
An assessment of chlorpyrifos‐methyl, etrimfos, fenitrothion and pirimiphos‐methyl as grain protectants
Authors: Thomas Keith P. , Pinniger David B. , Wilkin Douglas R. 
Published: November 2006

AbstractTrials were carried out over two consecutive years to compare the efficacy of chlorpyrifos‐methyl, etrimfos, fenitrothion and pirimiphos‐methyl against susceptible and organophosphorus‐resistant strains of Tribolium castaneum Herbst, Sitophilus granarius L. and Oryzaephilus surinamensis L., gamma‐HCH‐resistant strains of Acarus siro L. and Glycyphagus destructor Schrank, and a susceptible strain of Tyrophagus longior Ger‐vais. Pirimiphos‐methyl was not evaluated against the three mite species as data on the efficacy of this material had previously been published. Etrimfos and pirimiphos‐methyl were also tested against a susceptible and an organophosphorus‐resistant strain of Sitophilus oryzae L. Each pesticide was applied to two separate 20‐tonne batches of English wheat and stored under ambient conditions for 36 weeks. The efficacy of the pesticides was assessed regularly over the storage period using established bioassay techniques. However, chlorpyrifos‐methyl and fenitrothion were assessed against susceptible and resistant strains of S. granarius for 32 weeks only. Each of the four pesticides produced >95% mortality of the susceptible strain of all insect species tested for the entire duration of the trial with the exception of fenitrothion, when survival of T. castaneum increased after 32 weeks. Only fenitrothion failed to give 100% mortality of the resistant strain of S. granarius throughout the trial, but even so, the mortality was always >95%. Chlorpyrifos‐methyl, etrimfos and pirimiphos‐methyl gave much better control of the resistant T. castaneum than fenitrothion, and etrimfos gave slightly better control of resistant O. surinamensis than pirimiphos‐methyl which was in turn better than chlorpyrifos‐methyl at 36 weeks. Both etrimfos and pirimiphos‐methyl gave 100% mortality of the susceptible and resistant strains of S. oryzae. None of the pesticides maintained 100% kill of A. siro throughout the trial and fenitrothion failed to achieve this level of mortality after only 4 weeks. Etrimfos produced 100% mortality of the other two mites species tested throughout the trial, whereas both chlorpyrifos‐methyl and fenitrothion achieved this level of mortality for 32 weeks.
Biological activity of some new geraniol‐based diethers on insect pest and vectors
Authors: Phadnis Anil P. , Patwardhan Sarita A. , Gund Pushpa , Sharma Ravindra N. 
Published: November 2006

AbstractA series of 1‐benzyloxy‐ or 1‐phenoxy‐8‐alkoxy‐ and 1‐alkoxy‐8‐benzyloxy‐ or ‐8‐phenoxy‐3, 7‐dimethyl‐2, 6‐octadienes were prepared from 8‐hydroxygeranyl ethers obtained by oxidation of geranyl ethers. The effects of these new diethers on the development of mosquito eggs and larvae were examined. High hatching failure resulted from treatment of eggs. Freshly hatched as well as later larval instars also died. Juvenile hormone activity was inferred from metamorphic inhibition of hatched red cotton stainers. Oviposition deterrence against mosquitoes was a novel attribute of these compounds. The level of highest activity (1 mg litre‐1), though not comparable to the best known similar growth inhibitors, is nevertheless sufficient to merit continuing work on the more promising analogues suggested by the structure‐activity trends in the present series.
An analytical method for the determination of fluazifop‐butyl and fluazifop residues in soil
Authors: Patumi Maurizio , Marucchini Cesare , Businelli Mario , Vischetti Costantino 
Published: November 2006

AbstractA method is described for the analysis of soils for residues of the herbicide fluazifop‐butyl and its breakdown product fluazifop.Fluazifop‐butyl undergoes hydrolysis in the soil to fluazifop, which also has herbicidal activity. A procedure initially using dichloromethane and then methanol+aqueous sodium hydroxide for extraction has been developed and gives good recoveries of both fluazifop‐butyl and fluazifop in the 0.01–5 mg kg−1 range. After clean‐up, high‐performance liquid chromatography with u.v. detection at 245 nm or gas‐chromatography with mass framentography were used to determine the residue concentrations. The limit of detection was 0.05 mg kg−1 when h.p.l.c. was used and 0.01 mg kg−1 when g.c.‐m.s. was used.
Further observations on the enhanced degradation of iprodione and vinclozolin in soil
Authors: Walker Allan 
Published: November 2006

AbstractThe effects of soil pH on rates of degradation of iprodione and vinclozolin were measured in a silty clay loam soil. Little degradation of either fungicide occurred at pH 4.3 or 5.0, and degradation at pH 5.7 was slower than at pH 6.5. In both of the higher‐pH soils, the rate of loss of a second application of either fungicide was faster than that of the first, and a third application degraded even more quickly. In soil with pH 6.5, for example, the times for 50% degradation of iprodione following the first, second and third applications were about 30, 12 and 4 days, and for vinclozolin were 30, 22 and 7 days respectively. Iprodione degraded very rapidly in a sandy loam that had been treated three times previously with this fungicide and also degraded rapidly in the same soil pretreated three times with vinclozolin. Vinclozolin degraded rapidly in the vinclozolin pre‐treated soil, but its rate of loss in the iprodione pre‐treated soil was only slightly faster than in the previously untreated control. Studies of iprodione degradation in 33 soils from commercial fields demonstrated a clear trend towards faster rates of loss in soils with an extensive history of iprodione use. The time for 90% loss from previously untreated soils varied from 22 to 93 days. It varied from 16 to 28 days in soils treated once previously and from 5.2 to 23 days in soils treated twice previously. In soils that had received three or more previous doses, the time to 90% degradation varied from 3.8 to 15 days.
Tetcyclacis and triazole‐type plant growth retardants: Their influence on the biosynthesis of gibberellins and other metabolic processes
Authors: Rademacher Wilhelm , Fritsch Hansjoerg , Graebe Jan E. , Sauter Hubert , Jung Johannes 
Published: November 2006

AbstractReduction of shoot growth caused by the norbornanodiazetine derivative tetcyclacis and by the triazoles BAS 110¨ W, BAS 111¨ W and LAB 150 978 is probably due primarily to an inhibition of endogenous gibberellin (GA) formation. Treated plants are lower in biologically active GAs; reduction of shoot growth can be overcome by applying an appropriate dose of GA3; in the fungi Gibberella fujikuroi and Sphaceloma manihoticola the formation of GAs is inhibited by these compounds; in a cell‐free system of pumpkin endosperm the reactions leading from entkaurene to ent‐kaurenoic acid are blocked by relatively low concentrations of the growth retardants.The oxidative steps from ent‐kaurene to ent‐kaurenoic acid are known to be dependent on cytochrome P‐450. A structural feature common to tetcyclacis and the triazole‐type compounds is an sp2‐hybridised nitrogen atom located at the periphery of the molecule in a heterocycle. It appears likely that the lone electron‐pair on this atom interacts with the central iron atom of cytochrome P‐450 in the enzymes, resulting in inhibition.Previous work has shown that the activity of other enzymes containing cytochrome P‐450 is much less affected by these compounds than that of the ent‐kaurene oxidase. Therefore, it is concluded that distinct cytochrome P‐450 species occur in plants and that tetcyclacis, BAS 110 ¨ W, BAS 111 ¨ W and LAB 150 978 are efficient and specific inhibitors of GA biosynthesis at low concentrations. At higher concentrations and in special cases they may, however, also interfere with other metabolic reactions involving cytochrome P‐450.
Comparative activity of the enantiomers of triadimenol and paclobutrazol as inhibitors of fungal growth and plant sterol and gibberellin biosynthesis
Authors: Burden Raymond S. , Carter Geoffrey A. , Clark Terence , Cooke David T. , Croker Steven J. , Deas Adrian H. B. , Hedden Peter , James Carolyn S. , Lenton John R. 
Published: November 2006

AbstractThe nature and degree of the biological activity shown by triadimenol and paclobutrazol are influenced considerably by the absolute configuration of the two asymmetric carbon atoms present in the molecules. The order of the activity of triadimenol enantiomers was found to be: fungitoxicity—1S, 2R > 1R, 2R > 1R, 2S > 1S, 2S; inhibition of gibberellin biosynthesis—1R, 2S > 1S, 2S > 1R, 2R > 1S, 2R; and inhibition of plant sterol biosynthesis—1R, 2S≈1S, 2R > 1R, 2R > 1S, 25.The relative activity of paclobutrazol enantiomers was: fungitoxicity— 2R, 3R > 2S, 3R > 2R, 3S≈2S, 3S; inhibition of gibberellin biosynthesis—2S, 3S > 2R, 3S > 2R, 3R > 2S, 3R; and inhibition of plant sterol biosynthesis—2R, 3S > 2R, 3R > 2S, 3S > 2S, 3R. These data indicate that the R configuration at the chiral carbon bearing the hydroxyl group is the prime determinant for fungitoxicity whereas enantiomers having the S configuration at this carbon are effective inhibitors of gibberellin biosynthesis. This agrees well with published data for the structurally related vinylazoles.Plant sterol C‐14a demethylation was not always inhibited by enantiomers having high fungicidal activity thus indicating that the structural features necessary for binding to the plant C‐14a demethylase may differ from those needed for the analogous fungal enzyme.
Squalene epoxidase as the target of antifungal allylamines
Authors: Ryder Neil S. 
Published: November 2006

AbstractThe allylamine clinical antifungals naftifine and terbinafine inhibit ergosterol biosynthesis at the point of squalene epoxidation in a range of fungi pathogenic to man. Filamentous growth is particularly susceptible to this inhibition, cell death occurring at drug concentrations causing only partial inhibition of ergosterol biosynthesis. Susceptibility of yeast‐like fungi such as Candida species is more variable. Squalene epoxidase, a membrane‐bound enzyme, is the primary target of the allylamines. The C. albicans epoxidase is highly sensitive to the drugs and inhibition is unaffected by solubilisation of the enzyme. Squalene epoxidase from mammalian liver is orders of magnitude less sensitive to the allylamines. This selectivity appears to be partly due to interaction of the drugs with components of the soluble cytoplasm, but mostly due to intrinsic differences between the respective epoxidase enzymes.
The effect of some furochromene and benzochromene analogues of 2,2‐dimethyl‐7‐methoxychromene (precocene I) and benzofuran precursors on Oncopeltus fasciatus (dallas) and Locusta migratoria migratorioides (R&F)
Authors: Brooks Gerald T. , Ottridge Anthony P. , Mace David W. 
Published: November 2006

AbstractAs part of an extensive study on insect antijuvenile hormones (AJH) structurally related to 2,2‐dimethyl‐7‐methoxychromene and 6,7‐dimeth‐oxy‐2,2‐dimethylchromene (precocenes I and II, respectively), four furophenols, six furochromenes, three benzofuran derivatives and two benzochromenes were tested for biological effects on Oncopeltus fasciatus and Locusta migratoria. Exposure to ajar deposit of the chemical was used for O. fasciatus and topical application in acetone for L. migratoria, with precocenes I and II as standards for comparison. All compounds were toxic to O. fasciatus and in some cases, this may have concealed any potential AJH activity, which was not observed for any compound tested. Toxicity to L. migratoria was less evident and three of the furochromene derivatives, allprecocene‐I (PI) analogues, showed AJH activity seven to ten‐fold lower than that of PI. Neither of the benzochromenes tested showed any AJH activity. The results are discussed in terms of the known structure‐activity relationships for precocene‐like AJH activity.
Effect of the fungicide pyrifenox on sterol biosynthesis in Ustilago maydis
Authors: Masner Petr , Kerkenaar Antonius 
Published: November 2006

AbstractPyrifenox, a new pyridine derivative, proved to be an inhibitor of ergosterol biosynthesis, blocking the pathway at the C‐14 demethylation step in Ustilago maydis (CD.) Cor da. In treated sporidia the incorporation of [1‐14C]acetic acid into ergosterol and squalene was reduced and the incorporation into sterols which retain the C‐14 methyl group, mainly 24‐methylenedihydrolanosterol and obtusifoliol, was increased. In addition, treatment with pyrifenox markedly reduced the incorporation into sterol esters. It is possible that the methylated sterols may be unsuitable substrates for the esterification enzyme.
Behaviour of thiocarbamate herbicides in soils: Adsorption and volatilization
Authors: Ekler Zsigmond 
Published: November 2006

AbstractAdsorption and volatilization of cycloate, EPTC and vernolate applied to six types of soils were studied in the laboratory. Cycloate proved to be the most and EPTC the least adsorptive molecule in all systems examined, while the volatilization order of the compounds was the reverse EPTC>vernolate>cycloate. Neither the adsorption nor the volatilization of thiocarbamates was markedly affected by formulating agents. The adsorption isotherm of several systems did not obey the classical Freundlich equation. A reciprocal relationship which was found between the adsorption coefficients and the volatilization rates of thiocarbamates permits calculation of one of these properties if data on the other are available.
Effects of soil temperature on the efficacy of ergosterol biosynthesis inhibitor fungicides for control of Ustilago bullata
Authors: Falloon Richard E. 
Published: November 2006

AbstractThe effects of different soil temperatures on the efficacy of ergosterol biosynthesis inhibitor (EBI) fungicides applied as seed treatments for the control of seedling infection of prairie grass Bromus willdenowii (Kunth) by the head smut fungus Ustilago bullata (Berk.) were measured in a glasshouse experiment. The fungicides nuarimol, triadimefon and triadimenol+fuberidazole controlled infection at 17.5deg;C and below, but were less or non‐effective above 20.0°C. In a second experiment, nuarimol and propiconazole seed treatments reduced seedling emergence and caused stunting of seedlings, but these effects occurred equally over a range of temperatures from 15.0 to 27.5°C. Soil temperatures (3 cm depth) at a typical field site often exceeded 20°C during early autumn and late spring. Although EBI fungicide seed treatments show promise for U. bullata control, care will be required with their routine use because their efficacy in warm soils may be reduced, and they can have growth retardant effects on prairie grass seedlings.
The pyrethrins and related compounds. Part xxxi: Alkoxyimino‐substituted esters
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Khambay Bhupinder P. S. 
Published: November 2006

AbstractEsters derived from pyrethroidal acids and benzyl and furylmethyl alcohols bearing a wide range of side‐chains each containing at least one oxime ether group, and related derivatives of allethrin and benzylnorthrin, were synthesised and tested for insecticidal activity. Of the benzyl esters, the most insecticidal were those with the methoxyimino‐methyl or ‐ethyl side‐chains at C‐3 or C‐4, and with E configuration. Changing the alkoxy group, the configuration or the chain length resulted in lower activity. Introducing an occyano group increased activity if the side‐chain was at C‐3, but lowered it drastically if the substituent was at C‐4. In the case of allethrin, the methoxime derivative was less active than the parent ketone, but with benzylnorthrin conversion to the methoxime markedly increased activity against one of the test species.
Effects of low concentrations of vapour of the phenoxyalkanoic herbicide 2,4‐D‐butyl on growth of tomato plants
Authors: Breeze Victor G. 
Published: November 2006

AbstractTomato plants (5–7 weeks old)were exposed to a range of concentrations of vapour of 2,4‐D‐butyl (0.12–2.4 ng litre−;1), for periods of 6 or 24 h, using an air‐flow system. Net carbon dioxide exchange of the whole plant was measured for up to 2 days after exposure and was found to decrease in treated plants approximately in proportion to vapour concentration. Six weeks after exposure, shoot dry‐weights of plants exposed to herbicide vapour were less than control plants in all cases, by about 20 % or more. All characteristics measured were affected more by a 24‐h exposure period than 6 h, at the same vapour concentration. The amount of herbicide vapour, expressed as the product of exposure period and vapour concentration, gave a similar effect at a low range of vapour concentrations (≤1.0 ng litre−;1)and air‐flow rates of about 200 litre min−;1, but not at higher concentrations at a flow rate of about 120 litre min −;1. Better agreement between the experiments carried out at the two concentration ranges was obtained by expressing the herbicide vapour as the total amount to which the plants were exposed (i.e. the product of air‐flow rate, vapour concentration and duration of exposure)instead of concentration alone.
Adsorption and partial deactivation of chlorotoluron by burnt straw residues
Authors: Cotterill Edward G. 
Published: November 2006

AbstractAdsorption of chlorotoluron by straw ash is related to its carbon content. The ash has a high adsorptive capacity immediately after straw burning but this rapidly declines. The decline is probably due to leaching of an acid organic fraction from the ash. However, the reduced adsorption capacity is still sufficient to account for increases in chlorotoluron adsorption on sites where zero or minimum tillage leaves the ash at or near the surface of the soil.
Aldicarb degradation in sandy soils from different depths
Authors: Ou Li‐Tse , Rao Palakurthi S. C. , Edvardsson Knut S. V. , Jessup Ronald E. , Hornsby Arthur G. , Jones Russell L. 
Published: November 2006

AbstractAerobic and anaerobic degradation rates for aldicarb were measured in soil samples collected at different depths from a citrus grove near Davenport, Florida, together with the changes in concentration of its two toxic oxidation products, aldicarb sulfoxide and aldicarb sulfone. These data were used to estimate the first‐order rate‐constants for concurrent oxidation and hydrolysis of aldicarb, aldicarb sulfoxide, and aldicarb sulfone, and for the loss of total carbamate residues (TCR = aldicarb + aldicarb sulfoxide + aldicarb sulfone). Both oxidation and hydrolysis rate‐constants for aldicarb in surface samples (0‐30 cm) were larger than those in sub‐surface samples (30‐300 cm). Under aerobic conditions, microbial oxidation appeared to be the major route for aldicarb degradation in surface and shallow sub‐surface samples (30‐150 cm), whereas chemical hydrolysis appeared to be the dominant pathway in deep sub‐surface samples (150‐300 cm). Aldicarb in deep sub‐surface samples under anaerobic conditions was primarily degraded through hydrolysis and only trace amounts of aldicarb sulfoxide were detected. Time to 50% disappearance (DT50) values for TCR loss were generally invariant with depth. In sub‐surface samples, DT50 values under aerobic and anaerobic conditions were similar.
The effect of the mode of application on the toxicity of Androctonus australis hector insect toxin
Authors: De Dianous Serge , Carle Pierre R. , Rochat Hervé 
Published: November 2006

AbstractThe toxicity of the insect toxin from the venom of the scorpion Androctonus australis Hector (AaH IT) was assayed using several ethods of application on various insect species. Activity was only demonstrated by opical application on Musca domestica. Three different solvents were assayed: ethanol + water (50 + 50 by volume), acetone + water (80 + 20 by volume) and acetone + dimethyl sulphoxide (50 + 50 by volume). When using the last two mixtures, LD50 was found to be 1 μg 100 mg−1 fly. When this activity is compared to that of five synthetic insecticides tested in the same conditions, AaH IT is about 1‐5 times more active than propoxur and DDT, 10 times more active than malathion but 200 times less active than deltamethrin. No activity was observed against Aphis craccivora at 15 mg m−2 in surface‐contact tests on glass, or against Culex pipiens pipiens larvae at 2 × 105 ng litre−1 in water.
The physiological basis for the protective action of abscisic acid against diclofop‐methyl activity on Avena sativa L
Authors: Foreman Martin H. , Field Roger J. , Buick Rosalind D. 
Published: November 2006

AbstractPre‐treatment with abscisic acid (ABA) can protect oats (Avena sativa) against damage from the herbicide diclofop‐methyl. Examination of the uptake and translocation of diclofop‐methyl showed that although 20 μg ABA induced varying degrees of stomatal closure, ABA had no significant effect on the amount of herbicide entering the leaf. Translocation of [14C] diclofop‐methyl was also unafected by ABA treatment. Electrolyte leakage studies demonstrated that ABA prevented the loss of plasmalemma integrity normally associated with diclofop‐methyl damage. It was concluded that ABA protection was by active metabolism, and an increase in the tolerance of the plasmalemma to diclofop‐methyl.