bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyrethroid insecticides derived from 2,2‐dimethyl‐3‐(3‐phenoxybenzyloxy)propanal
Authors: Svendsen Axel , Pedersen Lars‐Erik K.
Published: November 2006

Fourteen oxime ethers and eleven other unsaturated compounds derived from 2,2‐dimethyl‐3‐(3‐phenoxybenzyloxy)propanal were synthesised and their insecticidal activity against Musca domestica, Locusta migratoria, Dysdercus cingulatus, Aedes aegypti, Plutella xylostella, Drosophila melanogaster, Tetranychus urticae and Spodoptera littoralis tested. Structural variations including chain length, branching and unsaturation of the oxime ether O‐alkyl group and substituent exchange at the carbon‐carbon double bond of the unsaturated compounds were made in order to examine the structure‐activity relationship. All biological activities were compared with the activity of the ether pyrethroid MTI‐500.
Synthesis and insecticidal activity of lipophilic amides. Part 1: Introductory survey, and discovery of an active synthetic compound
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A.
Published: November 2006

A group of naturally occurring isobutylamides and related compounds exhibit a range of biological properties including activity against insects. Their potential as a starting point for developing new insecticides, needed to control pests resistant to other classes of insecticides, is discussed, following an extensive survey of known structures and activities. Few of the known compounds were sufficiently active and well characterised to point to sound structure‐activity relationships, so synthetic analogues were examined. One of these [(2E,4E)‐N‐(2‐methylpropyl)‐6‐phenylhexa‐2,4‐dienamide] was sufficiently active, and prompted the investigations reported here and in subsequent papers in the series. Analogues of this compound designed to establish areas where structural variation is possible are also described.
Synthesis and insecticidal activity of lipophilic amides. Part 3: Influence of chain length and terminal group in N‐(2‐methylpropyl)‐2,4‐dienamides
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A.
Published: November 2006

Increasing the alkylene chain length in N‐(2‐methylpropyl)‐ω‐phenylalka‐2,4‐dienamides revealed in addition to the active compounds reported earlier a second peak of activity, but only against mustard beetles, with the tridecadienamide. Similar extension in the methyl‐terminated series gave much weaker peaks, at different lengths for the two test species. Results with terminal vinyl compounds were intermediate, and indicated a specific functional role in the lethal process for the terminal unsaturation, with a possible contribution to steric flexibility and physical property optimisation from the longer chains. Synthetic samples of pellitorine and pipercide, natural products to which insecticidal activity has been ascribed, were only very weakly active in the present tests, but compounds with other groups on the ends of chains nearer the optimum length were more active.
Influence of formulation on spray deposit patterns, dislodgeable and penetrated residues, and persistence characteristics of fenitrothion in conifer needles
Authors: Sundaram Kanth M. S. , Sundaram Alam
Published: November 2006

The influence of formulation on spray droplet spectra, deposit patterns, dislodgeable and penetrated residues, and persistence characteristics of fenitrothion in balsam fir needles was studied using three formulations containing different types of adjuvant. Spray was applied on to potted trees under controlled conditions in a laboratory chamber. Droplet size spectra and deposits were assessed using “Kromekote” cardlglass plate units. Foliar residues were measured by gas‐liquid chromatography.

The formulation containing polymeric adjuvants provided significantly larger droplets and higher foliar residues than those containing surfactants and co‐surfactants. It also provided a higher ratio of dislodgeable‐to‐penetrated residues, and a slower initial rate of loss of fenitrothion. None of the formulations posed a long‐term persistence problem because only very low amounts remained on foliage at 42 days post‐treatment. The significance of these findings in terms of the possible increase in bioavailability of the pesticide via crawling contact is discussed.
Confirmation and quantification of pesticide residues by mass spectrometry
Authors: Gilbert John , Startin James R. , Crews Colin
Published: November 2006

The sensitivity and specificity of mass spectrometry makes this an attractive technique for the confirmation and quantification of trace levels of pesticide residues. Two applications of mass spectrometry are outlined, that of combined headspace gas chromatography (g.c.)/mass spectrometry (m.s.), for the analysis of volatile fumigants such as ethylene dibromide (EDB) in imported fruits and multi‐residue halogenated compounds in bran products, and that of quantitative g.c./m.s. for the determination of a range of organochlorine pesticide residues. The approach to setting‐up a capillary g.c. multiple ion monitoring programme is described, with emphasis on quantitative aspects, and in particular the use of stable isotope internal standards. This is illustrated with an example of the quantification of organochlorine pesticide residues in eggs.
Studies into the action of the diphenyl ether herbicides acifluorfen and oxyfluorfen. Part II: The interaction with photosynthetic electron transport reactions
Authors: Gillham David J. , Dodge Alan D.
Published: November 2006

The effects of acifluorfen and oxyfluorfen on photosynthetic electron transport reactions of pea chloroplasts were compared with those induced by paraquat and monuron. Monuron inhibited electron flow between photosystems I and II, and paraquat acted as an electron acceptor for photosystem I, promoting superoxide formation by illuminated chloroplasts. Neither acifluorfen nor oxyfluorfen at concentrations up to 50 μM affected non‐cyclic electron flow or promoted superoxide formation. Both herbicides were shown to repress ferredoxin‐dependent NADP+ reduction by illuminated chloroplasts. Further experiments showed that, in the presence of ferredoxin‐NADP+ reductase and chloroplast membranes maintained in the dark, p‐nitro diphenyl ether (DPE) herbicides promoted the rate of ferredoxin‐dependent oxidation of NADPH, implying that these herbicides can accept electrons from reduced ferredoxin. The interaction between acifluorfen, ferredoxin and chloroplast membranes was examined further by following the effect of this herbicide on the peroxidation of illuminated thylakoids. Lipid peroxidation was promoted by acifluorfen, although this effect was abolished if thylakoids were washed prior to use. The effect of washing could be reversed by adding exogenous ferredoxin. These data demonstrate that interaction of DPE herbicides with photosynthetic electron transport in the vicinity of ferredoxin is necessary for light‐dependent herbicide activation.
Influence of composition of nutrient medium on the metabolism of chlortoluron in plant‐cell suspension cultures
Authors: Cole David J. , Owen W. John
Published: November 2006

The herbicide chlortoluron readily underwent oxidative metabolism in suspension cultures of cotton and maize. Major attack in cotton cells was by stepwise N‐demethylation followed by relatively slow ring‐methyl hydroxylation. The most prominent single metabolites seen after 1 day and 7 days were 3‐(3‐chloro‐p‐tolyl)urea and its benzyl alcohol analogue, respectively. In maize cells, ring‐methyl hydroxylation was apparently the preferred mode of metabolism. Only low amounts of the demethylated derivatives of chlortoluron were evident, and the major residues present at both 2 days and 7 days were the benzyl alcohol derivative of chlortoluron and 3‐(3‐chloro‐4‐hydroxymethylphenyl)‐1‐methylurea. In both species, a substantial proportion of the free ‘phase 1’ metabolites was initially expelled to the medium, but at later times, these were found largely within the cell as polar conjugates.

Two approaches were used to examine the influence of the composition of the medium on metabolism. Firstly, cells of both species were grown in four different nutrient media, which were selected to give variation in the organic nutrient and growth factor fraction; secondly, cells were grown in one medium, varying the level of 2, 4‐D. In cotton, the rate of metabolism of chlortoluron correlated with the extent to which the four media supported cell growth, Variations were also seen for maize but no correlation with growth rate could be made. For both species, metabolism was retarded when cells were sub‐cultured from a medium lacking coconut water to one containing 10% of this supplement. A fifty‐fold range in concentration of 2, 4‐D had little effect on metabolism in cotton, although a fall‐off in rate occurred at the highest level. However, in maize a marked trend towards accelerated metabolism with increasing content of 2, 4‐D up to 20 mg litre−1 was seen, which was independent of effects on growth.

The qualitative nature of chlortoluron metabolism in both species was unperturbed by substantial variations in the composition of the medium.
Phloem translocation of non‐ionised chemicals in Ricinus communis
Authors: Bromilow Richard H. , Rigitano Renê L. O. , Briggs Geoffrey G. , Chamberlain Keith
Published: November 2006

Techniques using R. communis were modified to enable the movement of chemicals in phloem and the factors controlling their distribution in the plant to be described quantitatively. The non‐ionised chemicals tested, aminotriazole, O‐methylcarbamoyloximes (including aldoxycarb and oxamyl) and phenylureas, spanning a range of lipophilicity of log KOW= −0.87 to +2.27, all freely entered the phloem. However, only the more polar compounds were retained sufficiently in the phloem to be transported over long distances, indicating that polar compounds cross cell membranes more slowly than compounds of intermediate lipophilicity; these findings substantiate the ‘intermediate permeability hypothesis’ of phloem translocation of xenobiotics. However, the amount of chemical reaching or retained in the sink tissues, especially in the root, was small even for the chemicals that were translocated best in the phloem.
Influence of carbaryl on nitrogenase activity and combinations of butachlor and carbofuran on nitrogen‐fixing micro‐organisms in paddy soils
Authors: Jena P. K. , Adhya T. K. , Rajaramamohan Rao V.
Published: November 2006

The influence of pesticides applied either singly or in combination on soil nitrogenase and nitrogen‐fixing micro‐organisms was investigated. Carbaryl, an insecticide commonly used in rice, had almost no effect on nitrogenase under submerged conditions while activity was stimulated even at 10 μg g−l under non‐flooded conditions. Application of the herbicide butachlor or the insecticide carbofuran (at 2 μg g−1) reduced the population of Azospirillum and anaerobic nitrogen fixers in a non‐flooded alluvial soil. In contrast, butachlor stimulated the population of anaerobic nitrogen fixers in an acid sulphate saline Pokkali soil under a similar water regime. Further, an increased level of carbofuran (4 μg g−1) stimulated the population of Azospirillum and anaerobic nitrogen fixers in both the soils. This stimulatory effect occurred, though not to the same extent, in the presence of butachlor which, when applied alone, inhibited the population of Azospirillum and anaerobic nitrogen fixers in alluvial soil. In Pokkali soil the combination of carbofuran and butachlor inhibited the population of Azospirillum, while carbofuran alone at 4 μg g−1 was stimulatory. These results suggest that under tropical conditions the effects of pesticides on nitrogen fixation and nitrogen‐fixing populations depend upon pesticide concentration, water regime and soil type.
Dissipation of propiconazole residues in and on wheat (Triticum aestivum L.)
Authors: Bai Qing‐Yun , Liu Chang‐Wu
Published: November 2006

In a 2‐year investigation, the dissipation of residues of the fungicide propiconazole from winter wheat straw and leaves was measured by periodic sampling of the green plant material from several plots that had been sprayed with ‘Tilt 2.50EC’ at three different rates.

The fungicide deposits on straw and leaves at day 0 were approximately one‐quarter of the dose applied on all treatment plots, and this fraction did not differ significantly between three dosage rates.

The fungicide residues disappeared rapidly, and the half‐life of the fungicide on straw and leaves was approximately 5 days. At harvest time, the fungicide residues in grain and soil were negligible, but the residues remaining on straw and leaves were considerable, especially at higher spraying rates than the recommended dosage.
Experimental design and response surface analysis of pesticide trials
Authors: Pike Derek J. , Hasted Anne M.
Published: November 2006

The search for combinations of pesticides or herbicides which have a synergistic effect is an important area of study and one which presents challenges for the statistician as well as for the experimenter. The aim is to find and to describe the interaction between a number of quantitative factors, and having done so to determine a combination which is economically optimal for a given level of control. The present paper discusses the role of a family of response functions called Inverse Polynomials to describe such phenomena. Examples are given of such functions and it is shown how it is possible to fit these functions to data and to plot the results on a routine basis. The importance of the experimental design for the estimation of such nonlinear regression models is investigated, and examples are given of experimental designs which are ‘optimal’ with respect to particular aims of the experimenter.
Studies on octylphenoxy surfactants. Part 1: Effects of oxyethylene content on properties of potential relevance to foliar absorption
Authors: Stevens Peter J. G. , Bukovac Martin J.
Published: November 2006

Selected properties of octylphenol and seven of its ethoxylated derivatives were studied as a preliminary to investigating their effects on the foliar absorption of three model compounds and the surfactants themselves. Surface tension of the surfactants (2 g litre−1 in water) increased with their hydrophile:lipophile balance (HLB) which is a function of oxyethylene (EO) content. The surface tension of the aqueous surfactants was inversely related to the cosine of their contact angle (θ) on maize leaf in the EO range 7.5–30. Cos θ was in turn related to the wetting of maize by aqueous acetone solutions of surfactants with EO >9.5. The critical surface tension required for complete wetting of the adaxial surface of maize leaf was estimated to be 29 mN m−1. Evaporation of drops of aqueous acetone solutions was biphasic, with preferential loss of acetone during the initial, more rapid phase. The rate of evaporation from the remaining, effectively aqueous systems was inversely related to the HLB of the surfactants. Phytotoxicity of the surfactants, as measured by ethylene production, increased with decreasing EO, while their hygroscopic water retention increased with both log EO and relative humidity (r.h.). Aqueous solubilities of pentacosane, DDT and atrazine were increased up to 8‐fold by surfactant (20 g litre−1). Maximum solubilities were observed with surfactants having intermediate HLB values. The solubility of pentacosane (maximum 221 μg litre−1) indicated that the surfactants would probably not solubilise more than 0.1% of the epicuticular wax when applied to maize leaf. Scanning electron microscopic observation of leaf surfaces exposed to surfactants for 24 h did not reveal any visible modifications of the wax structure. Volatilisation of DDT was reduced in the presence of surfactants but that ofatrazine was increased, although in inverse proportion to its solubility in aqueous surfactant.
The absorption of cypermethrin in the grasshopper Melanoplus sanguinipes (Fab.): Effects of volatilisation, temperature, age, sex and parasitisation by Malameba locustae (King and Taylor)
Authors: Hinks Christopher F. , Westcott Neil D. , Reichle Randy A. , Spurr David T.
Published: November 2006

The residues from metered doses of cypermethrin were recovered from excised portions of grasshopper cuticle to determine losses by volatilisation. Residues from similar doses were also recovered from the cuticles of intact grasshoppers and from whole body homogenates after rinsing the cuticle, to determine rates of absorption and losses from metabolism. Residues were recovered from males and females one week and three weeks after fledging in grasshoppers infected with Malameba locustae and in uninfected ones. They were maintained at 15 or 30°C and sampled from each combination of factors at 4, 8, 16, 24, 30 and 48 h after treatment. There was no measurable loss of cypermethrin by volatilisation up to 72 h after application to excised portions of cuticle at either 15 or 30°C. In all combinations of factors, more cypermethrin was recovered externally (P <0.05) from grasshoppers held at 15°C than those held at 30°C and more from infected grasshoppers than from those that were uninfected. Significantly more cypermethrin was also recovered externally from males than from females (P <0.05) and more from infected one‐week‐old grasshoppers than those that were three weeks old. At 15°C there was a gradual trend towards accumulation of cypermethrin internally, but at 30°C an initial trend towards accumulation was followed by one of decline. Residual cypermethrin recovered could in general be related to the negative temperature coefficient of toxicity, to a decreased sensitivity to cypermethrin in infected grasshoppers and to an increased sensitivity in older grasshoppers.
Efficacy of current and potential grain protectant insecticides against a fenitrothion‐resistant strain of the sawtoothed grain beetle, Oryzaephilus surinamemis L
Authors: Collins Patrick J. , Wilson Debra
Published: November 2006

The responses of a highly fenitrothion‐resistant and a susceptible strain of Oryzaephilus surinamensis L. from Australia were measured against a range of alternative grain protectants using impregnated‐paper and treated‐grain assays.

The R‐strain was also highly resistant to carbaryl, moderately resistant to malathion and pirimiphos‐methyl and showed low‐level resistance to methacrifos, chlorpyrifos‐methyl, bioresmethrin, permethrin, cyfluthrin, cypermethrin and dichlorvos. There was marginal resistance to deltamethrin. Methoprene, to which there was no resistance, was the most effective material at suppressing progeny production of the resistant strain. At current commercial application rates chlorpyrifos‐methyl was the only compound of those tested that would completely control both adults and larvae of resistant O. surinamensis for a storage period of nine months.

Overall, the homogeneity of response of both strains to insecticides using the treated‐grain assay was as good as the response from impregnated‐paper assays. The latter also tended to exaggerate resistance factors compared to the treated‐grain assays.
The cuticle, growth and moulting in insects: The essential background to the action of acylurea insecticides
Authors: Reynolds Stuart E.
Published: November 2006

The functions, structure and biochemistry of the insect cuticle in relation to the moulting cycle are briefly reviewed as an introduction to the actions of insecticides that act on the cuticle, particularly acylureas. The symptoms of poisoning with diflubenzuron (DFB) and other acylureas are consistent with ultra‐structural and biochemical evidence that these insecticides inhibit the formation of chitin microfibrils in newly synthesised cuticle. It is probable that DFB acts at a late stage in chitin biosynthesis, perhaps inhibiting chitin synthase (CS) itself. However, the results of studies using cell‐free preparations of CS have not, on the whole, supported this hypothesis. A number of alternative suggestions as to the mode of action of DFB are reviewed. Among the most attractive of these is the possibility that DFB may inhibit the transmembrane transport of chitin synthesis precursors from their site of production within the epidermal cells to the site of the final poly condensation reaction, presumably at the apical membrane of the epidermal microvilli.
Accumulation of malathion residues in grain stored on malathion‐treated wood surfaces
Authors: Mensah G. W. K.
Published: November 2006

Laboratory studies were conducted to determine whether insecticides applied to storage structures are able to move past a single layer of grain kernels to give adequate control of stored‐grain insects. The extent of uptake of insecticides was assessed on three layers of wheat in contact with wood surfaces treated with malathion 836 g litre−1 e.c. at 1–0 g a.i. m−2 using chemical and biological methods at predetermined time intervals. There was a progressive uptake of malathion beyond the layer directly in contact with the treated surfaces and the uptake depended on the duration of storage. After 8 weeks a sufficient amount of malathion accumulated on the top layer of grain kernels to cause 100% mortality of adult Tribolium castaneum (Herbst).
The conjugation and accumulation of metabolites of cypermethrin by earthworms
Authors: Curl Elizabeth A. , Edwards Peter J. , Elliott Clare , LeAhey John P.
Published: November 2006

When earthworms are maintained in soil containing [14C]cypermethrin they accumulate radioactive residues. These residues are not eliminated when the worms are transferred to untreated soil. The accumulated radioactive residue is a complex mixture of conjugates of two metabolites of cypermethrin (3‐phenoxybenzoic acid and (1RS)‐cis, trans‐3‐(2,2‐dichlorovinyl)‐2,2‐dimethylcyclopropanecarboxylic acid). One major constituent of this mixture of conjugates has been identified as N1, N12‐di‐(3‐phenoxybenzoyl)spermine. Feeding studies with quail and rats have established that the residues accumulated by the earthworms are not further bioaccumulated by earthworm predators.
The response of three soil fungi to dalapon and diuron treatments
Authors: Tan T. K. , Chua L. H.
Published: November 2006

Dalapon and diuron are two common herbicides used for the control of weeds. A study of the response of Gliocladium virens, Trichoderma hamatum and T. koningii in cultures to the herbicides was carried out. Changes in fungal colony morphology and growth and sporulation rates in the presence of up to 105 mg herbicide litre−1 were monitored. The three fungi were not adversely affected at a concentration of 103 mg litre−1. Changes in colony morphology and decreases in growth and sporulation rates were evident at the maximum test concentration (105 mg litre−1) of both herbicides. These generally recovered when the fungi were replated in the absence of the herbicides.
Potential new targets for herbicides
Authors: Dodge Alan D.
Published: November 2006

All 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

Duplicate 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

Trials 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

A 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

A 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

The 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

Reduction 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

The 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

The 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

As 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

Pyrifenox, 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

Adsorption 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

The 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

Esters 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

Tomato 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

Adsorption 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

Aerobic 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

The 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

Pre‐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.
Determination of total amitraz residue in honey by electron capture capillary gas chroma tography–a simplified method
Authors: Taccheo Maria Barbina , De Paoli Mauro , Spessotto Claudio
Published: November 2006

A gas chromatographic method using a capillary column is described for the determination of total amitraz residue in honey samples. The method consists of a preliminary extraction of the sample, an alkaline hydrolysis, an extraction of the 2, 4‐dimethylaniline formed, without the aid of steam distillation/continuous extraction, its derivatisation with heptafluorobutyric anhydride and a gas chromatographic determination using an electron capture detector. The method is very rapid and can be carried out in a test tube. The detection limit is 0.020 mg kg−1 and recoveries are of the order of 85%.
The synthesis and biological activity of some potentially fungicidal zinc ethylenebis(dithiocarbamate): Amine complexes
Authors: Clifford David P. , Carson Chrislyn M.
Published: November 2006

Thirty‐one complexes of zinc ethylenebis(dithiocarbamate), zineb, were synthesised and evaluated in comparison with zineb and mancozeb across a broad range of pathogens. The activity of zineb was greatly potentiated and its persistence increased against several pathogens, particularly Puccinia recondita. Use of an excess of particular amines provided a convenient method of analysis for zineb.