bluuebunny/crossref_metadata_2025 huggingface dataset:
The uptake, excretion and metabolism of the acylurea insecticide, flufenoxuron in spodoptera littoralis larvae, by feeding and topical application
Authors: Clarke Barry S. , Jewess Philip J.
Published: November 2006

Flufenoxuron is an acylurea insecticide which inhibits chitin synthesis. Its uptake, excretion and metabolism in larvae of Spodoptera littoralis have been measured. Larvae fed on a leaf disc sprayed at an application rate equivalent to 50 g ha−1rapidly absorbed a maximum of 20% of ingested flufenoxuron, the remainder being voided in the frass. Excretion of absorbed compound was slow, with a 50% excretion time of approximately 20 h. Flufenoxuron was equally effective as an insecticide by topical application or ingestion. Following topical application, a total of 11% of the dose had penetrated into the body within 24 h. Of this 11%, half had travelled to the gut so that the rest of the body tissues contained no more than 6% of the toxicant dose. The concentration of flufenoxuron in the body tissues was maintained for at least 24 h, the surface residue probably acting as a reservoir. The compound was metabolically quite stable. Following topical application the 6 % of the applied dose which was absorbed into the body was still 92% as unchanged flufenoxuron 24 h after application. The enhanced toxicity of flufenoxuron to S. littoralis compared with earlier acylureas can probably be attributed to its slower metabolism and reduced excretion.
Chemical and physico‐chemical characterization of wettable powder formulations containing copper
Authors: Galoux Michel , Bernes Albert
Published: November 2006

Eleven different commercial wettable powder formulations containing copper have been examined using standard CIPAC recommended techniques to determine the best chemical and physico‐chemical criteria for quality. This approach has allowed the setting‐up of a specification that retains only the essential criteria of quality control required for the official approval of a product of this type in Belgium.
Uptake by tomato plants of the herbicide [14C] 2,4‐D‐butyl in the vapour phase
Authors: Breeze Victor G.
Published: November 2006

Uptake of [14C‐phenyl]2,4‐D‐butyl by 4‐ to 6‐week‐old tomato plants was measured for vapour concentrations in the range 0.3–19 ng litre−1, for an exposure period of 4 h. Calculation of boundary layer thicknesses at the surface of the leaves, and depletion of the vapour concentration due to uptake by the plants, suggested that the plants experienced concentrations very close to the nominal values. Relationships between external vapour concentration and plant uptake, expressed in terms of fresh weight, leaf area, or on a whole plant basis, were linear in all cases. Twenty‐four hours after the commencement of exposure, leaves contained 63–93% of the total herbicide in the plant; the proportion retained by the leaves was greater at low vapour concentrations. The largest amount of herbicide was present in leaves from the mid‐position on the stem, but in terms of leaf area, the amount was greatest in leaves at the apex and decreased basipetally. It is not known whether this was due to a greater uptake rate per leaf area at the apex, or to translocation. As visible symptoms of phytotoxicity usually develop at the apex, both of these processes, together with the preferential retention of herbicide in leaves at low vapour concentrations, may all contribute to the development of vapour damage.
Effect of the fungicide imazalil on hepatic microsomal cytochrome P‐450 and cytochrome P‐450 dependent activities in the Bobwhite quail (Colinus virginianus)
Authors: Lavrijsen Karel , Van Houdt Jos , Van Dyck Dirk , Meuldermans Willem , Heykants Jos
Published: November 2006

Bobwhite quails were treated with imazalil for 8 weeks. The fungicide was given admixed in the food at 0, 100, 300, 500 and 1000 mg kg−1. Even at the highest dose tested, imazalil did not affect the liver weight or the hepatic microsomal protein content. In treated quails, no significant induction of cytochrome P‐450 or NADPH‐cytochrome c‐reductase activity was observed. Furthermore, imazalil did not induce or inhibit 7‐ethoxyresorufin or 7‐ethoxycoumarin O‐deethylase in quail microsomes. Only a slight but significant increase by 35% and 49% in aniline hydroxylase activity was measured for the 500‐ and 1000‐mg kg−1 dose levels, respectively. After a drug‐free period of one week, aniline hydroxylase activity returned to control values, indicating that the effect was fully reversible. It is concluded that imazalil does not induce or inhibit drug‐metabolizing enzymes in the quail, even at doses which exceed by far the maximum levels currently used to dress seed under field conditions (100 mg kg−1).
Effects of surfactants on water permeability of isolated plant cuticles and on the composition of their cuticular waxes
Authors: Riederer Markus , Schönherr Jörg
Published: November 2006

Treating the outer surfaces of isolated cuticles of Seville orange (Citrus aurantium L.) and pear (Pyrus communis L. cv. Bartlett) leaves with a number of nonionic (polyoxyethylene) surfactants increased their permeability to water by factors ranging from 4.1 to 14.7 and from 7.2 to 152.4, respectively. However, sodium dodecylsulphate, an anionic surfactant, had little effect on water permeability. In both species the major aliphatic constituents were n‐alkanes, 1‐alkanols and n‐alkyl esters. None of the surfactant treatments altered the amounts or composition of waxes in the cuticles used for transport measurements. The reasons for the apparent absence of solubilization or dissolution of cuticular waxes by nonionic surfactants are discussed and a hypothesis is presented for the mechanism by which activator adjuvants may increase the permeability of plant cuticles.
Insecticidal activity of 3‐isoxazolyl methanesulfonates and related compounds
Authors: Jacobsen Niels , Pedersen Lars‐Erik K. , Wengel Anita
Published: November 2006

Various methanesulfonates, notably of 3‐isoxazolols, exhibit interesting insecticidal activity, especially against Musca domestica and Locusta migratoria. Although the symptoms of poisoning are very similar to those caused by parathion, no correlation between in‐vitro inhibition of acetylcholinesterase and insecticidal activity was observed. This is also true for several methanesulfonates of hydroxy‐heterocycles and phenols included in this study for comparison.
2‐pyrazolines with herbicidal activity
Authors: Eussen Jac H. H. , Thus Jo L. G. , Wellinga Koos , Stork Bob
Published: November 2006

N‐(2‐pyrazolin‐1‐ylformyl)benzenesulfonamides form a new group of compounds with interesting herbicidal activity. Some of the chemical, biological and biochemical characteristics of this group are described. The herbicidal activity is mainly expressed as a post‐emergence activity on dicotyledonous weed species. The compounds appear to interfere with the biosynthesis of branched‐chain amino acids.
Inhibition of the processionary moth sex pheromone by some haloacetate analogues
Authors: Camps Francisco , Gasol Vicens , Guerrero Angel , Hernández Rodolfo , Montoya Ramón
Published: November 2006

Several haloacetate analogues of (Z)‐13‐hexadecen‐ll ‐ynyl acetate, the main component of the sex pheromone of the pine processionary moth Thaumetopoea pityocampa, have been found to be good inhibitors of the natural pheromone. In field tests, the fluorinated compounds exhibited higher antipheromone activity than the corresponding chlorinated analogues, the order of activity being monofluoro > difluoro > trifluoro > monochloro > dichloro > trichloroacetate. In EAG bioassays the trifluoroacetate analogue showed the highest inhibition effect among all the compounds tested. These results agree with others previously reported, and show the primary role played by the steric size of the halogen in these analogues in order to achieve a notable inhibition of the pheromone action.
The effects of low‐volume aeration on the residues and biological effectiveness of chlorpyrifos‐methyl applied to wheat
Authors: Thomas K. P.
Published: November 2006

The effects of low‐volume ventilation on the persistence and biological efficacy of chlorpyrifos‐methyl applied to English wheat were investigated. Four 20‐tonne batches of wheat were treated with a dose of 2.5 mg kg−1 chlorpyrifos‐methyl. After treatment, two of the batches were aerated continuously at a rate of 17 m3 h−1 tonne−1 (10 cfm tonne−1) for 16 weeks. The remaining two batches were not aerated. Samples were collected from both aerated and non‐aerated wheat at intervals over the 16‐week storage period and subjected to biological assay using laboratory multi‐organophosphorus‐resistant strains of Tribolium castaneum, Sitophilus granarius, Sitophilus oryzae and Oryzaephilus surinamensis. The samples were also analysed for chlorpyrifos‐methyl residues. No differences in either the biological efficacy or the rate of chemical decomposition were detected between the aerated and non‐aerated wheat.
Use of crystallographic data in searching for isosteric replacements: Composite crystal‐field environments of nitro and carbonyl groups
Authors: Taylor Robin , Mullaley Anne , Mullier Graham W.
Published: November 2006

Over 70 000 organo‐carbon crystal structures are available in the public domain. A common functional group may occur in several hundred of these structures. Examination of the immediate intermolecular environment of a functional group in each of the structures in which it occurs enables a composite crystal‐field environment to be determined. Although influenced by random packing forces, the composite environment may show strong systematic features which reflect the preferred interactions of the functional group. This is shown by test calculations on structures containing nitro and carbonyl groups, using in‐house software. Strong systematic features exist in the composite environments of both groups, showing their tendency to hydrogen bond in approximately the directions of the oxygen lone pairs, and to participate in strong electrostatic interactions in the direction normal to the plane of the group. Such results are of value in aiding the search for bioisosteres.
Imidazolinone herbicides: Synthesis and novel chemistry
Authors: Wepplo Peter
Published: November 2006

The imidazolinone herbicides were prepared from reaction of an α‐ methylvaline fragment with an o‐dicarboxylic acid. Early syntheses were completed through an imide amide intermediate, such as I or XV, followed by further cyclization to 2,5‐diones III or XXI. Reaction of these diones with nucleophiles led to imidazolinones IV and V. The significant and interesting activity of these compounds led to new and versatile methods of synthesis, including resolution of the α‐methylvaline fragments, development of a metallation‐carboxylation route, a one‐step picoline to imidazolinone route, and several pyridine and fused‐ring pyridine syntheses.
A field unit for determining dimethoate in fruit and vegetable dips
Authors: Noble Alan , Walsh John J. , Outhwaite Robert J.
Published: November 2006

The concentration of dimethoate in post‐harvest dips needs to be maintained at 400 or 500 mg litre−1 to ensure that fruit fly are killed and also to keep residue levels below the MRL. A field unit which contains a colorimeter, a heating block and cooling positions has been evaluated. The diluted dip sample produces a colour with 4‐(p‐nitrobenzyl)pyridine after heating and the addition of tetraethylenepentamine. Precision of the unit was acceptable for a field test (repeatability of ± 10.1%) and there was reasonable agreement between determinations made on the unit and by an HPLC method for a range of dimethoate concentrations from 300 to 700 mg litre−1. The unit can be used at the dip site and the analysis is completed in 30 minutes.
Inhibition of calmodulin‐dependent enzymes in rat brain by hexachlorocyclohexane
Authors: Basavarajappa B. S. , Salimath Bharathi P.
Published: November 2006

Ca2+ homeostasis is one of the major regulatory mechanisms operating in the nervous system, with calmodulin translating the Ca2+ message into cellular response. To check if hexachlorocyclohexane (HCH) acts as a calmodulin antagonist in the nervous system of rats, the in‐vitro effect of HCH on calmodulin‐dependent Ca2+‐ATPase and cAMP‐phosphodiesterase (PDE) in rat brain has been studied. In the membrane fraction from rat brain, a basal activity of Ca2+‐ATPase was obtained in the absence of Ca2+. Inclusion of Ca2+ (1 mM) increased the enzyme activity by 70%. Further, addition of fluphenazine, a potent calmodulin antagonist, inhibited the Ca2+‐dependent enzyme activity (IC50 = 85 μM), demonstrating the calmodulin dependence of the enzyme activity. The Ca2+‐ and calmodulin‐dependent Ca2+‐ATPase was inhibited by HCH in a dose‐dependent manner (IC50 = 80–90 μM). Ca2+‐ and calmodulin‐dependent cAMP‐PDE from the cytosolic fraction of rat brain was inhibited by HCH (340 μM) by 79%. Addition of excess calmodulin reversed the inhibitory effects of HCH or fluphenazine on Ca2+‐ATPase and cAMP‐PDE, suggesting their direct interaction with calmodulin. By fluorescence interaction studies it has been shown that HCH interacts directly with calmodulin. These studies show that HCH may modulate the intracellular concentration of Ca2+ and cAMP, by decreasing the effectiveness of calmodulin towards its effector enzymes, resulting in an altered signal transduction in the nervous system.
Effects of bifenox and oxadiazon on isolated chloroplasts, plant mitochondria and leaf pieces
Authors: Routaboul Jean Marc , Nurit Françoise , Ravanel Patrick , Tissut Michel
Published: November 2006

The effects of bifenox (methyl 5‐(2,4‐dichlorophenoxy)‐2‐nitrobenzoate) and oxadiazon (5‐tert‐butyl‐3‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐1,3,4‐oxadiazol‐2(3H)‐one on photosynthetic activity were investigated in isolated chloroplasts, and on respiratory activity in isolated mitochondria. The global effects of these chemicals were also investigated on cucumber cotyledon pieces. It was found that, in vitro, bifenox and oxadiazon acted on cotyledon pieces as typical diphenyl ether herbicides, causing complete pigment bleaching, even at low concentrations. In addition, bifenox and oxadiazon were shown to inhibit the photosynthesis process at the chloroplast level. At concentrations of up to 40‐50 μM, oxadiazon and bifenox were observed to inhibit fully the light‐dependent oxygen evolution of spinach class A chloroplasts, oxadiazon acting preferentially on electron transfer at the PS II level whereas bifenox acted on the photophosphorylation process. Comparison of the amounts of herbicide needed to inhibit photosynthesis and to cause bleaching of cucumber pieces leads to the conclusion that photosynthesis inhibition by bifenox and oxadiazon is only a secondary effect.
Comparative metabolism and disposition of [14C‐benzyl] cypermethrin in quail, rat and mouse
Authors: Edwards Robert , Millburn Peter , Hutson David H.
Published: November 2006

The excretion and metabolism of cis + trans‐[14C‐benzyl] cypermethrin has been compared in quail, rat and mouse. Radioactivity was rapidly eliminated by quail dosed orally with [14C]cypermethrin (2 mg kg−1), as was the case in the rat and the mouse. When the birds were dosed intraperitoneally (IP) with the 14C‐labelled pyrethroid, radioactivity was excreted more slowly than after oral dosing, and almost 20% of the IP dose of 14C remained in the tissues after 7 days. Both mammalian species excreted [14C]cypermethrin more rapidly than did the avian species after IP administration, and less than 6% of the dose remained in their tissues after several days. The biotransformation of the pyrethroid was more complex in the avian species (34 metabolites) than in the two mammals (some 10 metabolites in each species). In quail the predominant reactions were ester bond cleavage of cypermethrin together with either aromatic hydroxylation or amino acid conjugation of the 3‐phenoxybenzyl moiety. The hydroxylated derivatives were eliminated mainly as sulphates. 3‐Phenoxybenzoic acid was conjugated with a variety of amino acids including glycine, taurine, glutamic acid, serine, α‐N‐acetylornithine and the dipeptide glycylualine. The last two conjugations are unique to avian species. The major metabolite of cypermethrin in the rat was the sulphate conjugate of 3‐(14‐hydroxyphenoxy)benzoic acid, whereas in the mouse the major products were 3‐phenoxybenzoic acid and its taurine conjugate. Thus, in the mammalian species where hydroxylation was maximal, amino acid conjugation was a minor metabolic route und vice versa. However, in the quail, aromatic hydroxylation and amino acid conjugation of the 3‐phenoxybenzyl moiety of cypermethrin were both major reactions. The influence of the rates and sites of metabolism, and of the enzymology of amino acid conjugation, in determining this species difference are discussed. The rapid metabolism of cypermethrin to a variety of polar conjugates that are readily excreted, together with the low brain sensitivity of birds compared with mammals to its neurotoxic effects, explains the low acute toxicity of this pyrethoid to avian species.
The phototransformation of a bis‐2,3‐diazabutadienyldisulfide to an aphicidally active 2,3‐dihydro‐1,3,4‐thiadiazole
Authors: Farooq Saleem , Steinemann Adrian , Schlaepfer Theophil
Published: November 2006

The pro‐insecticide bis‐(1‐(4‐chlorophenyl)‐4‐(pyrid‐3‐yl)‐2,3‐diazabutadien‐1‐yl)disulfide, I is photochemically transformed to the aphicidally active 5‐(4‐chlorophenyl)‐2‐(pyrid‐3‐yl)‐2,3‐dihydro‐1,3,4‐thiadiazole IIa.
Correlation of fluridone and dye concentrations in water following concurrent application
Authors: Fox Alison M. , Haller William T. , Shilling Donn G.
Published: November 2006

Herbicide residue samples are expensive and time‐consuming to collect and analyze. To test whether Rhodamine WT dye could simulate the dissipation of fluridone, concurrent applications of the chemicals were made in the weed‐infested Three Sisters tidal canals (Citrus Co. Fl) and a shallow lake in the Upper St Johns River, Florida. Dye concentrations were measured using a field fluorometer and fluridone concentrations were analyzed by an HPLC method. The coefficient of correlation between dye and herbicide was 0.99 in the canals and 0.93 in Lake Hell ‘n’ Blazes (Upper St Johns River) over 340 and 93 h respectively. Half‐lives of the chemicals were not significantly different for either site. The importance of these data in relation to herbicide registration is discussed.
A scanning electron microscope study of glyphosate deposits in relation to foliar uptake
Authors: Macisaac Susan A. , Paul Rex N. , Devine Malcolm D.
Published: November 2006

The effects of several formulations on foliar uptake of glyphosate, and on the morphology of glyphosate deposits on leaves, were examined in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.). [14C]glyphosate, in the form of the free acid or the isopropylamine salt (IPAS), was applied to foliage alone or with various adjuvants. Uptake of all glyphosate IPAS formulations was greater than that of the corresponding acid formulation. Addition of ‘Tween 20’ enhanced the uptake of glyphosate IPAS compared to glyphosate alone, but had no effect on the uptake of glyphosate acid. Ammonium sulfate and the ‘Roundup’ formulation blank increased the uptake of glyphosate acid and IPAS to 2‐3 times that of herbicide alone.

Surface deposits, as observed by scanning electron microscopy, varied with the formulation of the herbicide, although there were no differences between the acid and IPAS formulations. Glyphosate alone initially formed a deposit with both crystalline and smooth, amorphous areas. Later in the treatment period (48 and 72 h after application), the deposit was almost entirely crystalline. The addition of ‘Tween 20’ or of formulation blank resulted in the formation of a more amorphous, non‐crystalline deposit. Herbicide solutions containing ammonium sulfate dried to form a highly crystalline deposit. However, crystals similar to those of glyphosate alone were not visible in these deposits. The ability of these adjuvants to prevent or delay crystal formation may play a role in their enhancement of herbicide uptake.
The herbicide binding niche of photosystem II‐a model
Authors: Tietjen Klaus G. , Kluth Joachim F. , Andree Roland , Haug Michael , Lindig Markus , Müller Klaus H. , Wroblowsky Heinz J. , Trebst Achim
Published: November 2006

The QB binding niche of photosystem II is also the binding site for many different herbicides. In order to understand the mode of binding of the herbicides, a 3‐dimensional model of the binding niche was constructed. The model was based upon a comparison of the known structure of the QB binding niche in purple bacteria with sequence and mutant data of the D‐1 protein of photosystem II.

Plastoquinone builds up hydrogen bonds to phenylalanine 265 backbone amide nitrogen, to serine 264 hydroxyl, and to histidine 215 delta‐1 nitrogen. In addition to these hydrogen bond donors and acceptors, herbicides can build up hydrogen bonds to backbone carbonyl of alamine 263 and to serine 268 hydroxyl. This is supported by binding data of inhibitors in Chlamydomonas reinhardtii chloroplasts of wild type and of five D‐1 protein mutants (Ser264 Ala, Ala251 Val, Phe255Tyr, Val2191le, Leu275Phe).
Determination of petroleum oil deposits on Citrus sinensis (L.) Osbeck leaves
Authors: Allender William J. , Beattie G. Andrew C.
Published: November 2006

Oil deposited on citrus leaves when sprayed with oil‐in‐water emulsions was measured by gas‐liquid chromatography of a hexane/acetone/water/ethyl acetate extract of the leaves. To overcome the problem of decreased recoveries with increased time between spraying and extraction, a refluxing step was included in the procedure followed by Florisil clean‐up prior to analysis. Mean oil recoveries of 81% were obtained and, unlike recoveries using published methods, they were independent of time between application and extraction. The method is intended to be used in trials to determine the relationship between spray volume, Chinese wax scale mortality and petroleum oil deposition on citrus leaves sprayed by low‐, medium‐ and high‐volume sprayers.
The metabolism in the rat of the herbicidally active isomer (R)‐ flamprop‐methyl in comparison with the racemic form
Authors: Hutson D. H. , Logan C. J. , Taylor B.
Published: November 2006

A single dose (4 mg kg−1) of 14 C‐labelled (R)‐flamprop‐methyl to rat was rapidly metabolised and 90% of the dose was eliminated in urine and faeces within 48 h. Four days after dosing, tissue residues were 0–1 μg equivalents g−1 tissue or much less, with the exception of kidney (0–22 μg g−1). There was a statistically significant sex difference in the routes of elimination; this may be attributed to differences in the biliary elimination of the major metabolite, flamprop acid, or its glucuronide conjugate. The fate of racemic flamprop‐methyl was very similar to that of the (R)‐isomer. The major metabolic routes were hydrolysis of the esters to the corresponding acids, hydroxylation of the benzoyl aromatic rings and conjugation. The flamprop acid derived from the (R)‐flamprop‐methyl was found to be partially converted to the (S)‐form (R:S ratio, 87:13). This reaction is discussed in the context of other such biological racemisations recently reported.
Separation of pesticides, related compounds, polychlorobiphenyls and other pollutants into four groups by silica‐gel microcolumn chromatography (application to surface water analysis)
Authors: Leoni Valerio , Cremisini Carlo , Casuccio Alessandra , Gullotti Antonio
Published: November 2006

Multi‐residue analyses of pesticides and related compounds generally require clean‐up procedures for the elimination of interfering substances.

An analytical procedure for use in the recovery and determination of pesticides and other pollutants in water samples is described, in which the purification of the extracts is improved by the separation of pesticides into four groups.

The separation of pesticides by silica‐gel microcolumn chromatography is explained in detail.
Synthesis and biological activity of 4‐aikoxy‐ and 4‐ω‐aminoalkoxy‐2‐trichloromethylquinolines
Authors: Szabó Zoltán , Enisz János
Published: November 2006

A number of new 4‐alkoxy‐ and 4‐ω‐aminoalkoxy‐2‐trichloromethyl‐quinolines were synthesised and tested on insects, weeds and plant pathogens. Many of these compounds showed antifungal activity against different fungal species. Some compounds, IVa, IVb, IVc, Vb, Vc and VI, had interesting effects on Phycomycete fungi.
Fate and short‐term persistence of permethrin insecticide injected in a northern Ontario (Canada) headwater stream
Authors: Sundaram Kanth M. S.
Published: November 2006

1·275 dm3 of a l·3g dm−3 aqueous emulsion of permethrin (i.e. 1·658 g permethrin) was applied to the surface of a fast‐flowing stream by manual injection. Water samples were collected from the top 1‐cm layer at different intervals of time at various distances downstream from the site of application. Caged samples of stream detritus, crayfish, brook trout and stonefly nymphs, bottled sediment and potted aquatic plants were placed 280 m from the treatment site, and collected afterwards for residue analysis. The downstream movement of the chemical was not uniform with peak concentrations of about 12 ng ml−1 at 30 m and 0·1 ng ml−1 at 730 m from the treatment site. The peak concentrations (ng g−1) in potted aquatic plants, caged detritus, crayfish and brook trout were about 18, 39, 14 and 11 respectively. The residues were higher than the ambient water concentration (1·67 ng ml−1) and dissipated slowly. The peak concentration in the bottled sediment was 2·75 ng g−1, and the residues were lost rapidly. In contrast, the naturally occurring sediment in a beaver pond showed high residues that persisted for a longer period of time. Permethrin concentrations in invertebrate drift ranged from 9 to 357 ng g−1, depending on the distance from the application site. The study demonstrated that aquatic invertebrates, plants and stream detritus acted as the major sink for the chemical.
Influence of fungicidal control of cucumber and tomato grey mould (Botrytis cinerea) on fruit yield
Authors: Yunis Hisham , Elad Yigal , Mahrer Yitzhak
Published: November 2006

The fungicides tebuconazole, tebuconazole + dichlofluanid, fenethanil, diethofencarb + carbendazim, and vinclozolin combined with chlorothalonil were tested for their ability to control grey mould (Botrytis cinerea Pers. ex Fr.) of cucumber and tomato grey mould in greenhouses under commercial conditions. In winter 1987/88 the number of diseased female fruits of cucumber (Cucumis sativus L.) was reduced by diethofencarb + carbendazim (2·5 mg dm−3 each) by 93% and by tebuconazole (2·5 mg dm−3)(phytotoxic when alone) or tebuconazole (1 mg dm−3) + dichlofluanid (4 mg dm−3) by 54–57%. Vinclozolin (5 mg dm−3) + chlorothalonil (25 mg dm−3) significantly reduced disease incidence on fruits by 40%. Infection foci on cucumber stems were significantly decreased by vinclozolin + chlorothalonil. A more pronounced decrease was obtained with diethofencarb + carbendazim, tebuconazole, or tebuconazole + dichlofluanid. During the season of winter 1988/89, tebuconazole + dichlofluanid (1·5 + 6 and 3 + 12 mg dm−3) and RH7592 (1 mg dm−3) significantly reduced diseased fruits by 30–71%. Grey mould of tomato (Lycopersicon esculentum Mill.) leaves was reduced by more than 90% and on fruits by 78–87% when tebuconazole + dichlofluanid (1·5 + 6 and 3 + 12 mg dm−3) or diethofencarb + carbendazim (2·5 mg dm−3 each) were applied. Yields of cucumber fruits of the common parthenocarpic cv. Kasem 292 were weighed. There was no correlation between disease level and yield in any experiment, plot or date except for two measurements. Compesation in fruit production by the plant may be regarded as the reason for no positive yield response to efficient control. The possibility of reducing fungicide application is discussed. Control of grey mould on tomato resulted in yield increase.
2‐Benzyloxy‐6,8‐Dioxabicyclo[3.2.1]Octanes: New carbohydrate‐derived herbicides
Authors: Blattner Regine , Furneaux Richard H. , Mason Jennifer M. , Tyler Peter C.
Published: November 2006

Structure—activity relationships in a new group of ‘cyclic ether’ herbicides have been probed by synthesis and evaluation of a range of isomers and analogues of 1,f‐anhydro‐4‐O‐benzyl‐3‐deoxy‐2‐O‐methyl‐β‐D‐gluco‐pyranose. The absolute and relative stereochemical arrangement of the benzyloxy‐ and methoxy‐groups and the pyran‐ring oxygen atom possessed by this compound were essential for herbicidal activity, but the directionality of the —CH2O— bridge unit was not. The benzyl substituent could be modified, especially by ortho‐substitution on the benzene ring, without significant loss of herbicidal activity, but the azido‐, ethoxy‐ and allyloxy‐groups were the only replacements for the methoxy‐group that did not result in a significant loss of potency. Selectivity for weeds in broad‐leaf crops was enhanced by the introduction of an alkyl or substituted alkyl group at the anomeric carbon.
Allylamine antimycotics: Recent trends in structure—activity relationships and syntheses
Authors: Nussbaumer Peter , Ryder Neil S. , Stütz Anton
Published: November 2006

Methods developed for the synthesis of terbinafine‐related allylamine antimycotics are reviewed. The synthesis of the en‐yne side chains were generally accomplished by means of organometallic reactions. The use of Pd0‐catalysed coupling reactions allowed easy access to derivatives bearing sensitive side‐chain substituents. As examples, four metabolites of terbinafine were prepared via this procedure.

Investigations with the carbon analogue of terbinafine revealed that, within the allylamine antimycotics, the nitrogen appears to be necessary for penetration by the drug into the fungal cell.

Replacement of the naphthalene moiety of terbinafine by optionally substituted benzo[b]thiophenes led to a number of derivatives with high antifungal activity. A series of benzo[b]thienyl compounds with the side chain at position 7 and different substituents at position 3 showed significantly increased activity against Candida albicans in vitro. In particular, the 3‐chloro derivative with the allylamine side chain at position 7(SDZ 87–469) proved to be the most potent allylamine antimycotic reported to this date.

Two novel types of lead structures, the homopropargylamines and the benzylamines show very high activity in vitro.
Systemic transport of tritiated phosphonate in tomato plantlets (lycopersicon esculentum mill)
Authors: d'Arcy‐Lameta Agnès , Bompeix Gilbert
Published: November 2006

Phosphonate uptake and distribution were evaluated in tomato plantlets by direct determination and by autoradiography. The rate of root uptake was linear during the 2 h of assay, suggesting active transport of the molecule. Phosphonate was readily taken up through the roots and translocated to the leaves, which contained the molecule within 2 min of root application. Autoradiography showed that phosphonate was transferred apoplastically by veins and progressively entered the lamina by symplastic transport. After a root loading of 2 h, plants were transferred to water and phosphonate levels were evaluated over the following 3 days: the concentrations in roots increased with a corresponding decrease in phosphonate levels in the leaves. These experiments demonstrated the ambimobility of phosphonate.
Study of pesticides in waters from a chalk catchment, cambridgeshire
Authors: Clark Lewis , Gomme Joe , Hennings Susan
Published: November 2006

WRc are undertaking a long term study of pesticides in the aquatic environment. A study of the pesticides in the rain, river water and groundwater of the Granta catchment in Cambridgeshire is now in its fourth year. Preliminary results are presented and the concentrations of agricultural pesticides in environmental waters are related to the land‐use within the catchment.

The Granta study is incomplete but certain anomalies in pesticide occurrence can be identified. In particular, the triazines are much more prevalent in the groundwaters than their agricultural usage would lead one to expect.

The limited data base gives problems with modelling the contaminant transport in groundwater. The present situation is reviewed and areas of future work necessary to fulfil the modelling needs identified. These areas of study.

The historical land‐use and pesticide usage; the groundwater quality data base; the pesticide transport in the unsaturated zone.
Simultaneous recording of neurophysiological effects and toxicological symptoms of cypermethrin poisoning in intact larvae of Spodoptera littoralis boisd
Authors: Broderick Mark P. , Leake Lucy D. , Ford Martyn G. , Greenwood Richard , Crichton Raymond
Published: November 2006

A method is described for simultaneous recording of in‐vivo nerve activity and toxicological symptoms from 6th‐instar larvae of Spodoptera littoralis poisoned with insecticide. Topically applied doses (9 ng‐180 μg insect−1) of cypermethrin induced hyperactivity, repetitive activity and bursting in the ventral nerve cord; these activities were associated with different stages of poisoning in the whole animal and are consistent with pharmacokinetic studies. Nerve activity continued long after the larvae appeared to be dead (i.e. up to 5‐6 days), although microscopic examination of these larvae revealed that they were still capable of small movements. At the lower doses (up to the LD95) time to death was inversely proportional to dose. Death of the organism may be related to the number of neurones which are affected by the insecticide.
Determination of bifenthrin in pumpkins by gas chromatography and mass spectrometry
Authors: Wei Lester Y.
Published: November 2006

The pyrethroid insecticide bifenthrin was used for control of the squash bug Anasa tristis Deg. on pumpkins. An analytical method has been developed for analysis of bifenthrin residues in pumpkins. The maximum bifenthrin residue found was 0·007 mg kg−1. The bifenthrin residue was also examined by combined gas chromatography/mass spectrometry in the electron impact mode with selected ion‐monitoring for detection.
The dissipation of 1,3‐dichloropropene in ditch bottom sediment and associated aerobic ditch water
Authors: Yon Denis A. , Morrison Grant A. , McGibbon Alec S.
Published: November 2006

The aerobic aquatic metabolism of [14C]1,3‐dichloropropene has been studied in two ditch waters and their associated sediments using a modification of the requirements of Section G.2. of the Dutch Registration Guidelines.

Preliminary experiments showed that (a) the evaporation of 1,3‐dichloropropene from water had a half‐life of less than 5 h, and (b) in a soil/water slurry, 1,3‐dichloropropene was rapidly converted to 3‐chloropropenoic acid.

In the definitive experiment conducted in two sediments, the overall recovery of radioactivity was good (84·5%) given the volatile nature of the chemical. In both sediment types, 1,3‐dichloropropene evaporated rapidly from water. In the Letcombe samples (organic silty clay loam) more radioactivity was associated with the sediment (40%) than ditch water (5%) than in Marcham samples (medium clay, 12% in sediment and 10% in water) and this may reflect the organic matter content of the two sediments (10·5% and 2·9% respectively). The 1,3‐dichloropropene in the ditch water was rapidly converted to 3‐chloropropenoic acid and other minor polar products. The material in the soil was not investigated further.
Deposition, mobility and persistence of sprinkler‐irrigation‐applied chlorpyrifos on corn foliage and in soil
Authors: Don Wauchope R. , Young John R. , Chalfant Richard B. , Marti Luz R. , Sumner Harold R.
Published: November 2006

The insecticide chlorpyrifos (O,O‐diethyl O‐3,5,6‐trichloro‐2‐pyridyl phosphorothioate) was applied to sweet corn (Zea mays L.) by chemigation, injecting either an emulsifiable formulation or technical chlorpyrifos dissolved in soybean oil into 0·25 cm or 1·27 cm sprinkler‐applied irrigation water. Half of the plots treated with chlorpyrifos in 0·25 cm water were immediately irrigated further with 1·27 cm water without chlorpyrifos. Half the plots treated with chlorpyrifos in 1·27 cm water were irrigated with another 1·27 cm water without chlorpyrifos 10 days later. Neither the volume of water used to apply the insecticide nor subsequent irrigation affected chlorpyrifos residues on the corn foliage or in the soil. Chemigation of the soybean oil solution resulted in three times more chlorpyrifos on the foliage than chemigation of the emulsion formulation, apparently because of greater adhesion of the oil droplets to the foliar surface. Chlorpyrifos residues in foliage declined with an initial half‐life of one day. Chlorpyrifos on or near the soil surface declined with an initial half‐life of approximately four days.
The toxicity of mptp (1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine) to Periplaneta americana l. and its effects on dopamine in the cerebral ganglia
Authors: Owen Michael D.
Published: November 2006

MPTP (1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine) and MPP+ (1‐methyl‐4‐phenylpyridinium ion) are potent dopaminergic neurotoxins in mammals. The mammalian toxicity of MPTP depends on its conversion, by monoamine oxidase, to MPP+. MPTP is toxic to cockroaches (LD50 720 μg gm−1) and the results suggest that MPTP toxicity depends on monoamine oxidase activity at a site outside the nervous system. MPTP depletes dopamine from cockroach cerebral ganglia and MPP+ inhibits cockroach mitochondrial respiration. While the biochemistry of MPTP toxicity appears to be the same as in mammals it seems that insects are unable to detoxify MPTP before its action has fatal consequences outside the nervous system.
Is sulfotep a proctolin receptor antagonist?
Authors: Wood Sarah J. , Osborne Richard H.
Published: November 2006

Proctolin‐induced, dose‐dependent (10−8‐2 × 10−6 M) contraction of the isolated foregut of Schistocerca gregaria was antagonised non‐competitively by sulfotep (2 × 10−6‐10−5 M). A higher dose of sulfotep (5 × 10−5 M) caused restoration of the proctolin dose‐response curve to its control value. Neostigmine (10−5 M) caused non‐competitive inhibition of proctolininduced tissue contraction. Increasing the dose of neostigmine to 10−4 M restored the proctolin response to control values. Sulfotep (10−5 M) and neostigmine (10−4 M) caused inhibition of acetylcholinesterase (AChE) activity in tissue homogenates obtained from guts pretreated with either drug for 20 min. The stimulatory effect of sulfotep (5 × 10−5 M) on proctolin‐induced gut contraction was abolished by pretreatment of tissues with atropine (10−6 M). Under these conditions, 5 × 10−5 M sulfotep caused further antagonism of the action of proctolin. The results suggest that sulfotep is a proctolin receptor antagonist in the locust foregut. However, higher concentrations inhibit tissue AChE activity, thereby allowing endogenous acetylcholine to activate muscarinic receptors. This leads to enhanced tissue contractility which masks the antagonistic effect of sulfotep on proctolin‐induced contraction.
Synthesis and mosquito repellent properties of some 2‐alkyl‐N‐acetyloxazolidines
Authors: Taylor Wesley G. , Schreck Carl E.
Published: November 2006

Twenty 2,3‐disubstituted oxazolidines, mostly with an alkyl group at C‐2 and an acetyl group at N‐3 have been synthesized and evaluated in the laboratory as mosquito repellents. Repellent activity was assessed in two bioassays with three mosquito species, using a human arm as bait. In patch tests, oxazolidines with an n‐hexyl, n‐heptyl or n‐octyl group showed better activity than those with shorter or longer side chains. In stocking tests, prolonged repellency of selected oxazolidines was evident against Anopheles quadrimaculatus. Some of these experimental chemicals, for example N‐acetyl‐2‐octyl oxazolidine, warrant further investigations as potentially useful insect repellents.
A rapid method for the determination of liquid fumigant residues in food commodities using automated headspace analysis
Authors: Norman Kevin N. T.
Published: November 2006

An automated gas chromatographic headspace method capable of detecting halogenated compounds in cereals, nuts and seeds at levels down to μg kg−1 or less has been developed and evaluated. Commodities were analysed directly without extraction or clean‐up and a simple calibration technique offers a rapid screening quantitative analytical method. Comparison of results obtained using an established solvent extraction method with those obtained using the method described showed good quantitative agreement. Minimum detectable quantities were lower using the headspace method for every fumigant residue/commodity studied. The recommended analytical conditions are suitable for examination of further commodities for the fumigant residues examined and for other volatile halocarbons.
Influence of formulations and adjuvants on the rainfastness of maneb and mancozeb on pea and potato
Authors: Kudsk Per , Mathiassen Solvejg K. , Kirknel Erik
Published: November 2006

The rainfastness of the residual fungicides maneb and mancozeb was assessed on pot‐grown pea (Pisum sativum L) and potato (Solanum tuberosum) plants using a rain simulator. Suspension concentrate formulations were generally retained better than wettable powder formulations. The rainfastness of the fungicides was found to be inversely related to particle size and this partly explained the differences observed between the formulations. Three mm rain applied at a high intensity (27 mm h−1) washed‐off more fungicide than 3 mm applied at a low intensity (3 mm h−1). Addition of various adjuvants significantly improved the rainfastness of the fungicides on both plant species. Oil adjuvants, however, only increased the rainfastness on pea. Furthermore, addition of a latex‐based adjuvant was found to reduce the redistribution of mancozeb on potato leaves.
Mechanisms responsible for propoxur resistance in the german cockroach, Blattella germanica (L.)
Authors: Siegfried Blair D. , Scott Jeffrey G.
Published: November 2006

The mechanisms of propoxur resistance were studied in a strain (Baygon‐R) of the German cockroach (Blattella germanica (L.)) displaying high levels of resistance by topical application compared to a susceptible laboratory strain (CSMA). The penetration of [14C] propoxur was significantly slower in the resistant strain, and resistance was reduced 3.4‐fold when the insecticide was injected compared to topically applied, implicating decreased cuticular penetration as a resistance mechanism. In‐vivo metabolism studies employing [14C]propoxur indicated that propoxur was metabolized at a faster rate in the resistant strain. Resistance to propoxur was partially suppressed by both piperonyl butoxide and S,S,S‐tributyl phosphorotrithioate suggesting the involvement of both cytochrome P450‐dependent mono‐oxygenases and hydrolytic enzymes in the resistance mechanism. In vitro, the Baygon‐R strain displayed higher rates of NADPH‐dependent microsomal metabolism of [14C]propoxur associated with the formation of o‐hydroxy propoxur and N‐hydroxymethyl propoxur, further implicating the monooxygenase system in the resistance. In‐vitro metabolism of [14C]propoxur with cytosolic fractions indicates that the substrate is lost from the incubation mixture at a higher rate in the Baygon‐R strain, possibly due to hydrolytic enzymes that result in production of expired [14C]carbon dioxide. The bimolecular inhibition constants for propoxur against acetyl‐cholinesterase from resistant and susceptible strains were not different. These results indicate that increased levels of metabolism together with decreased rates of penetration are mainly responsible for resistance to propoxur in this strain.
Some effects of abamectin on neural activity in larval instars of Spodoptera littoralis boisduval and Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)
Authors: Christie Paul T. , Broderick Mark P. , Wright Denis J.
Published: November 2006

The spontaneous action potential (AP) frequencies recorded from an in‐vivo ventral nerve cord (VNC) preparation of abamectin‐treated insects not showing signs of paralysis (asymptomatic) were significantly (P < 0.05) less than those from untreated insects for fifth‐ and sixth‐instars of Helicoverpa armigera (24 h) and Spodoptera littoralis (24 and 48 h) after topical application of abamectin. There were also significantly (P < 0.05) less APs from abamectin‐treated insects showing signs of paralysis than from asymptomatic abamectin‐treated insects. Significantly (P < 0.05) more radioactivity (and abamectin) was recovered from VNCs of larvae showing signs of poisoning (paralysis) than from asymptomatic‐treated insects. There were also significant (P < 0.001) correlations between the levels of radioactivity (as log dpm) recovered from VNCs and the AP frequency (Hz) after 24 h for both instars and species and after 48 h for S. littoralis. AP frequencies did not decline significantly (P < 0.05) in abamectin‐treated sixth‐ and fifth‐instar S. littoralis larvae until respectively 4 and 8 h after treatment. In conclusion, significant correlations were found in the present study between electrophysiological events in the VNC, visible symptoms of poisoning, and accumulation of abamectin within the VNC. An inverse relationship was found between the levels of abamectin in the VNC and the level of spontaneous nervous activity. These observations are compatible with the VNC being a target site for abamectin. However, the relative importance of the VNC versus peripheral nerves, neuromuscular junctions and muscles as target sites is not known and requires further clarification. No differences in the sensitivity of the VNC to abamectin were found between fifth‐ and sixth‐instar S. littoralis larvae, though there is limited evidence for the H. armigera VNC being less sensitive than the S. littoralis VNC to abamectin.
The HPLC determination of residues of maleic hydrazide in cloves of garlic bulbs following foliar application
Authors: Cessna Allan J.
Published: November 2006

A method was developed for the extraction and HPLC analysis of the plant growth regulator maleic hydrazide (MH) from garlic bulbs. Recovery of MH from fortified garlic tissue was 75.8(±6.1)% at the 1 and 2 mg kg−1 fortification levels. MH residues were determined by HPLC in cloves of garlic bulbs following treatment at three sites in southern Ontario with foliar applications at 3.75 kg ha−1. MH residues in the cloves were in the order of 3 mg kg−1 at two sites, and 11 mg kg−1 at the third side.
Actions of imidacloprid and a related nitromethylene on cholinergic receptors of an identified insect motor neurone
Authors: Bai Donglin , Lummis Sarah C. R. , Leicht Wolfgang , Breer Heinz , Sattelle David B.
Published: November 2006

Nitromethylenes and their analogues are a novel class of insecticidally active molecules of commercial importance. Here we describe the actions of a novel nitroguanidine analogue, l‐(6‐chloro‐3‐pyridylmethyl)‐N‐nitroimidazolidin‐2‐ylideneamine (imidacloprid; NTN 33893) and a nitromethylene, l‐(3‐pyridylmethyl)‐2‐nitromethylene‐imidazolidine (PMNI) on the cockroach fast coxal depressor motor neurone Df and their effectiveness in displacing [125I]α‐bungarotoxin binding to cockroach nerve cord preparations. When tested on the cell body of this identified neurone both imidacloprid and PMNI induce slow depolarizations, which are sensitive to nicotinic receptor antagonists, such as dihydro‐β‐erythroidine (1.0 × 10−5 M) and mecamylamine (1.0 × 10−4 M). Lower concentrations of imidacloprid (1.0 × 10−8 −1.0 × 10−6 M) and PMNI (1.0 × 10−8 M) show no antagonist action on nicotine‐induced depolarization. At concentrations in the range 1.0 × 10−7 −5.0 × 10−7 M, PMNI partially and reversibly blocks nicotine‐induced depolarization. Both compounds are more effective displacers of specific [125I]α‐bungarotoxin binding than nicotine, with imidacloprid (IC50 = 2.0 × 10−7 M) about tenfold more potent than PMNI (IC50 = 1.3 × 10−6 M).