bluuebunny/crossref_metadata_2025 huggingface dataset:
Activity of rocaglamide, an insecticidal natural product, against the variegated cutworm, Peridroma saucia (lepidoptera: noctuidae)
Authors: Satasook Chutamas , Isman Murray B. , Wiriyachitra Pichaet
Published: November 2006

Physiological and behavioural effects of rocaglamide, an insecticidal natural product, were determined for the variegated cutworm, Peridroma saucia, using different bioassays. Rocaglamide inhibited growth of neonate P. saucia in a dose‐dependent manner when incorporated into an artificial diet. The dietary EC50 (effective concentration inhibiting growth by 50% relative to controls) was 1·37 mg kg−1. Lethal doses causing 50% mortality (LD50) of fourth‐instar larvae were 0·32 and 0·34μg larva−1 for topical and oral administration, respectively, based on a 96‐h observation period. Mortality did not become significant until at least 72 h following administration. Rocaglamide applied to cabbage leaf discs or incorporated into artificial diet had a moderate antifeedant effect towards larvae in choice tests. Nutritional experiments with fourth‐instar larvae using dietary exposure or following topical application confirmed that rocaglamide possessed both antifeedant and toxic effects. Direct assays of feeding behaviour indicated that behavioural effects could not account for the complete bioactivity observed. Significant impairment of larval growth following topical administration, concomitant with reduced food consumption, suggests that rocaglamide may act partially through central inhibition of the feeding process, leading to anorexia.
Bioaccumulation and elimination of endosulfan in zebra fish (Brachydanio rerio)
Authors: Toledo M. Cecilia F. , Jonsson CláUdio M.
Published: November 2006

The bioaccumulation and elimination of endosulfan in zebra fish (Brachydanio rerio) were investigated in a semi‐static bioassay. The pesticide mean concentration in water was 0.3 μg litre−1 and the level of endosulfan residues (α‐+β‐isomers+endosulfan sulfate) in the exposed fish at day 21 was 0.81 (±0.12) μg g−1 body weight. The estimated value of the bioconcentration factor (BCF) was 2650 (±441), the total endosulfan residues being eliminated with a biological half‐life of four days. Histopathological studies showed predominantly lipid accumulation in the liver and necrotic focus in the gills of exposed fish.
Interaction of azole fungicides and related compounds with cytochrome‐P450 isozymes from Penicillium italicum in in‐vitro assays
Authors: Kapteyn Johan C. , Milling Richard J. , Simpson Donald J. , De Waard Maarten A.
Published: November 2006

The interaction of various sterol demethylation inhibitors (DMls) and experimental compounds with cytochrome‐P450‐dependent sterol 14α‐demethylase (P45014DM) from Penicillium italicum was studied by difference spectroscopy using a preparation of microsomal P450 isozymes and assays with cell‐free extracts capable of synthesizing ergosterol from [14C]mevalonate. The EC50 values (concentrations of compounds which inhibited radial growth of P. italicum by 50%) of the compounds ranged from 3 × 10−8 M to levels higher than 10−3 M. All the compounds investigated gave type II difference spectra and interfered with the binding of carbon monoxide (CO) to microsomal P450 isozymes. However, the differences in the IC50 values (concentrations of compounds which caused 50% of maximal type II spectral change) between compounds and their inhibition of CO binding did not correlate with the fungicidal activity of the compounds. Hence, neither type II difference spectra nor CO‐displacement tests with microsomal preparations from this fungus can be used for studying the selective fungitoxicity of azoles. Data obtained using the cell‐free sterol 14α‐demethylase assay revealed larger differences between the compounds in their inhibition of sterol 14α‐demethylation. The I50 values (concentrations of compounds which inhibited cellfree sterol biosynthesis by 50%) varied from 4.3 × 10−9 to 4.4 × 10−5 M. This assay was able to rank the compounds in order of fungitoxicity, but the I50 and EC50 values did not correlate quantitatively. Consequently, the observed differential inhibition of P45014DM activity between the compounds cannot fully explain their selective fungitoxicity. Additional mechanisms must be involved. The present study supports the general opinion that the affinity of azoles for P45014DM depends on the nature of their N1 substituent. However, it was demonstrated that the nature of the azole moiety was also of importance in determining the affinity of DMIs for P45014DM.
Structure‐activity relationships of insecticidal amides from Piper guineense root
Authors: Gbewonyo Winfred S. K. , Candy David J. , Anderson Moray
Published: November 2006

The structure‐activity relationships between five amides previously isolated from the root extract of Piper guineense Schum and Thonn were studied. The methyl‐terminated amides, pellitorine and kalecide, were found to be more polar and caused higher knockdown, but showed less lethal action against insects than their methylenedioxyphenyl‐terminated counterparts, pipercide and guineensine. Guineensinamide showed weak activity and this was correlated with higher unsaturation and the presence of a pyrrolidyl group in the molecule. There was an association between the polarity of the amides and the recovery of the insects from their effects, much more recovery being observed with the methylterminated than with the methylenedioxyphenyl‐terminated amides. Electrophysiological investigations of the effects of pellitorine and pipercide on miniature excitatory postsynaptic potentials (MEPSPs) from the locust retractor unguis nerve‐muscle preparation showed that the amides caused a reduction in both the frequency and amplitude of MEPSPs, pipercide being between 100 and 1000 times more effective than pellitorine. An action of the amides on presynaptic transmission is suggested. The effects of pipercide and pellitorine on the isolated nerve‐muscle preparation were correlated with the symptoms of poisoning at the whole animal level.
Phototransformation of the insecticide hydramethylnon in aqueous systems
Authors: Chakraborty Subhasish K. , Bhattacharyya Anjan , Chowdhury Ashim
Published: November 2006

Sunlight irradiation of hydramethylnon in aqueous media of different pH values resulted in 80‐94% transformation within 10h. The rate of disappearance of the insecticide was affected marginally by the initial pH of the reaction medium. After 10 h irradiation, eight photoproducts were formed. Three products were isolated as pure crystalline substances and the structures of two of these (I & III) were characterised by mass and NMR spectroscopy. The reaction mechanisms involved in the formation of photoproducts are discussed.
Study of the enhancement of herbicide activity and rainfastness by an organosilicone adjuvant utilizing radiolabelled herbicide and adjuvant
Authors: Roggenbuck Frank C. , Penner Donald , Burow Richard F. , Thomas Bryan
Published: November 2006

‘Sylgard® 309’ organosilicone surfactant is a very effective adjuvant for broadleaf weed control with a number of herbicides. It is also effective in providing rainfastness lo these post‐emergence herbicide applications. To elucidate the basis for herbicide activity enhancement and rainfastness, the absorption of [14C]acifluorfen, [14C]bentazone and [14C]‘Sylgard 309’ were studied. Non‐ionic surfactants and crop oil concentrates were used as adjuvants with [14C]acifluorfen and [14C]bentazone, respectively, for purposes of comparison. Maximum absorption of [14C]acifluorfen and [14C]bentazone was obtained within 15 min after herbicide application with the organosilicone, versus ≥ 24 h with the convenlional adjuvants. [14C]‐Organosilicone absorption closely paralleled that of the [14C]‐herbicides. The organosilicone appears to exert its action by increasing greatly herbicide absorption. The enhancement effect did not appear to be a function of reduced surface tension. Rainfastness appeared to be a result of greatly accelerated herbicide penetration through the leaf cuticle in the presence of the organosilicone.
Oils for weed control: Uses and mode of action
Authors: Gauvrit Christian , Cabanne Ferdinand
Published: November 2006

The role of oils in herbicide treatments is reviewed, both in terms of their own intrinsic activity and of their enhancement of the performance of other herbicides. The phytotoxicity of oils can be related to their physical properties. Their efficacy as adjuvants can vary with the plant/pesticide combination involved, and differences may also be observed between oils of mineral and vegetable origin. The possible mechanisms involved in the enhancement of activity by oils are discussed and areas of work that might elucidate these fun her are indicated.
Influence of wetting agents on the foliar uptake and herbicidal activity of glufosinate
Authors: Köcher Helmut , Kocur Jean
Published: November 2006

The influence of four different wetting agents on the foliar retention, uptake and herbicidal activity of the glutamine synthetase inhibitor, glufosinate, was examined in growth‐chamber experiments on barley (Hordeum vulgare L. cv Roland) and barnyard grass (Echinochloa crus‐galli (L.) P.B.) as test species.

The non‐formulated monoammomum salt, glufosinate‐ammonium, was applied as a spray, either alone or mixed with a wetting agent. The dose rates of herbicide and wetting agent were 0.5 g a.i. litre−1 and 2.0 g litre−1, respectively, on barnyard grass, and 2.0 g a.i. litre−1 and 60 g litre−1, respectively, on barley. Herbicide damage, rated 10 days after spraying, was greatest when glufosinate was used with a sodium C12/C14‐alcohol‐diglycolether sulfate (FAEO‐sulfate) and least with polyoxyethylene (POE)(8) tridecyl ether; intermediate effectiveness was obtained with a combination of herbicide and a POE(15) tridecyl ether or POE(15)‐tallow amine.

The activity of the target enzyme, glutamine synthetase, measured 2 h after spraying, was reduced most when FAEO‐sulfate was present and least with POE(8) tridecyl ether.

The behaviour of the glufosinate wetting agent solutions on plant foliage was analysed by measurements of spray retention, droplet contact angles and foliar uptake of [14C]glufosinate. The results led, for both grass species, to the conclusion that differential ability of the wetting agents to enhance the permeation of glufosinate from the leaf surface deposit into the leaf tissue was the main factor responsible for the differences in herbicidal effectiveness of the glufosinate/wetting agent combinations used in this study.
British and European community regulations and registration requirements for non‐pesticidal co‐formulants in pesticides and for adjuvants
Authors: Chapman Peter J. , Mason Robert D.
Published: November 2006

Pesticides in Great Britain are subject to legislation that requires them to be approved by Ministers. Specific data for non‐pesticidal co‐formulants are not generally required but are encompassed within the requirements for the formulated pesticide in which they are present. Adjuvants, substances without significant pesticidal properties which enhance the effectiveness of a pesticide when added to that pesticide, can be used with pesticides only in accordance with the approval of that pesticide or as varied by lists of authorised adjuvants published by Ministers. Data must be supplied for adjuvants to appear on this list. National legislation on pesticides is soon to be amended to take account of a European Community Directive which seeks to harmonise registration requirements throughout the Community. It is as yet unclear how this will affect registration of co‐formulants and adjuvants.
Extended summaries sci pesticides group symposium third international symposium on adjuvants for agrochemicals. Structure and chemistry of plant cuticles
Authors: Holloway Peter J.
Published: November 2006

The following are extended summaries based on papers presented at a meeting of the Physicochemical and Biophysical Panel of the SCI Pesticides Group, held on 3‐7 August 1992 at Churchill College, Cambridge University. Cambridge, UK. The summaries published here are entirely the responsibility of the authors and do not necessarily reflect the views of the Editorial Board of Pesticide Science.
High‐performance liquid chromatographic method for the determination of carbendazim residues in crops, grains, and wines with fluorescent detection
Authors: Regis‐Rolle Sylvaine D. , Bauville GéRard M.
Published: November 2006

A normal‐phase high‐performance liquid chromatographic method is described for the determination of carbendazim in wine, cereals and fruits. Residues are extracted from samples with methanol. Preliminary liquid partitioning into hexane may be necessary, according to the crops, followed by liquid partitioning from aqueous solution into dichloromethane. Purification is performed by silica‐column chromatography or with a silica solid‐phase extraction cartridge. Determination and quantification are made by HPLC using an aminobonded stationary phase with fluorescent detection at 285/315 nm. Recoveries range from 80 to 95% for various fortification levels. The method provides a minimum detectable amount below 0.1 ng and quantification limits for various samples are between 0.01 mg kg‐1 and 0.1 mg kg‐1.
Studies on octylphenoxy surfactants: XI. Effect on NAA diffusion through the isolated tomato fruit cuticular membrane
Authors: Knoche Moritz , Bukovac Martin J.
Published: November 2006

The effect of a homologous series of octylphenoxy surfactants [2‐{α‐[4‐(1,1,3,3‐tetramethylbutyl)phenoxy]poly(2‐ethoxy)}ethanol;‚ Triton‐X’︁ series], with five (TX‐45), 9–10 (TX‐100), 16 (TX‐165) and 40 (TX‐405) units of ethylene oxide (EO) on penetration of NAA [2‐(1‐naphthyl)acetic acid] through enzymatically isolated tomato (Lycopersicon esculentum Mill.) fruit cuticles was investigated. Surfactant effects on NAA flux were related to EO chain length and to surfactant concentration, compared on a basis relative to the critical micelle concentration (CMC, 2.5 × CMC and CMC/2.5). At concentrations above the CMC, TX‐45 and TX‐100 increased NAA flux 2.5‐ and 1.5‐fold, respectively, while TX‐165 was without effect and TX‐405 decreased NAA flux 0.7‐fold. At concentrations below the CMC, all four surfactants increased NAA penetration by 1.1‐ to 1.3‐fold. Time‐course studies of NAA flux on addition of surfactant revealed that, where NAA flux always increased it did so slowly, but any decrease of flux occurred rapidly. Sorption of NAA by cuticular membranes decreased progressively with increased EO chain length at surfactant concentrations 2.5 × CMC. Below the CMC, surfactants had little or no effect on NAA sorption. Our data provide evidence that surfactants increase transcuticular penetration of NAA by increasing the diffusion coefficient and, hence, the mobility of NAA in the cuticle.
Porphyric insecticides. IV: Structure‐activity study of substituted phenanthrolines
Authors: Gut Larry J. , Lee Keywan , Juvik John A. , Rebeiz Carole C. , Bouton Carl E. , Rebeiz Constantin A.
Published: November 2006

The porphyric‐insecticide‐modulating activities of 1,10‐phenanthroline and eight of its analogs were investigated. The insecticidal efficacy of these compounds was closely associated with their ability to enhance the conversion of exogenous δ‐aminolevulinic acid (ALA) to protoporphyrin IX (Proto). As observed for photodynamic herbicidal effects in plants, the presence of nitrogen atoms at positions 1 and 10 of the macrocycle was essential for porphyric insecticidal activity. This was evidenced by the very limited activity of phenanthrene, in which positions 1 and 10 are occupied by carbon instead of nitrogen atoms. On the other hand, enhancement of Proto formation and porphyric insecticidal activity were maintained following methyl, chloro and nitro group substitution at the periphery of 1,10‐phenanthroline. In contrast, Proto levels and photodynamic toxicity were reduced by hydroxy and phenyl substitution at the same positions. Benzyl substitution at the 2–3 and 8–9 positions was also inhibitory. Quantitative structure‐activity calculations suggested a relationship between peripheral group substitution and physicochemical properties of the substituted compounds. Electron density changes in 1,10‐phenanthroline and its analogs that appeared to be related to reduced efficacy included (a) appearance of positive charge‐binding volumes at positions 4 and 7 of the 1,10‐phenanthroline macrocycle, which flanks positive charge‐repelling volumes, (b) a dramatic increase in superdelocalisability (i.e. electron density) over some unoccupied molecular orbitals, and (c) electronic charge at positions 1 and 10 of the macrocycle. Large increases in van der Waals volumes also exerted negative effects on insecticidal efficacy.
Spirosultam LY219048: A new chemical class of insecticide acting upon the GABA receptor/chloride ionophore complex
Authors: Bloomquist Jeffrey R. , Jackson Johnny L. , Karr Laura L. , Ferguson Holly J. , Gajewski Robert P.
Published: November 2006

This study assessed the toxicity and mode of action of a new experimental insecticide, LY219048 in insects and mammals. LY219048 produced rapid convulsions in mice and had LD50 values of 0.7 mg kg−1 and 4 mg kg−1 after intracerebral and intraperitoneal injection, respectively. In initial screens against insects, LY219048 showed low activity against the German cockroach (Blatella germanica L.). Lethality from dietary exposure required one to two weeks, even at concentrations as high as 10000 mg kg−1 (LC50 = 485 mg kg−1). In contrast, it had an LC50 value of 8.3 mg kg−1 against insecticide‐susceptible Drosophila melanogaster (Meig.) when synergized with piperonyl butoxide. Significant resistance to LY219048 (> 12‐fold) was detected in a cyclodiene‐resistant strain of D. melanogaster possessing an altered target site resistance mechanism. This finding suggested that LY219048 blocked the 4‐aminobutyric acid (GABA)‐gated chloride channel in a manner similar to that of the cyclodienes. In physiological studies in larval D. melanogaster central neurons, LY219048 antagonized the reduction of firing caused by 1 mM GABA. Dose‐response experiments showed that the ED50 for blocking inhibition under these conditions was c. 1 μ. Studies of 36CI uptake into bovine brain synaptosomes found that LY219048 was a potent antagonist. At 10 μ it completely blocked chloride flux stimulated by 50 μM GABA. LY219048 competitively displaced [3H]TBOB binding from bovine brain membranes, with an IC50 of 42 nM, which was comparable to values determined for TBPS (35 nM) and picrotoxinin (267 nM). There was little or no displacement (<25%) of [3H]flunitrazepam or [3H]muscimol binding by 10 μM LY219048. Taken together, these results provide strong evidence that this new chemical class of insecticide manifests its acute toxicity by blocking the GABA‐gated chloride channel.
Measurement of evaporation from adjuvant solutions using a volumetric method
Authors: Hall Franklin R. , Kirchner Loren M. , Downer Roger A.
Published: November 2006

Various agricultural spray adjuvants are available which are classified as anti‐evaporants. This quality has the potential to aid in reducing drift and chemical evaporation and so improving coverage. Numerous other adjuvants not claiming these benefits may have these characteristics which are not being exploited. In order to assess these qualities, a simple, rapid assay was devised for measuring relative evaporation rates from individual drops. This method was then used to measure the evaporation rates of a variety of adjuvants under controlled temperature and humidity conditions.

The droplet producing device uses a microliter syringe to dispense a droplet of known size. After a given period of time, the drop is taken back into the syringe and the volume lost to evaporation calculated. Modifications to the original device include suspending the drop inside a temperature‐ and humidity‐controlled chamber.

The original device was used for determining the rate of evaporation from water drops later than 0.3 mm. We have extended the use of the device to measure the rates of evaporation from a range of adjuvant solutions under controlled temperature and humidity conditions. The data reported here suggest that this method (a) is suitable for measuring evaporation from drops of many (but not all) adjuvant formulations, (b) is capable of discerning differences in relative rates of evaporation and (c) may be used for an array of adjuvant, drop size, and meteorological conditions. Major limitations appear to be (1) equilibrium surface tension, solutions having values less than c.35 mN m −1 are difficult to analyze and (2) a lower limit on drop‐size of c.300 μm.
Removal of paraquat by adsorption on ‘waste’ Fe(III)/Cr(III) hydroxide: Adsorption rates and equilibrium studies
Authors: Namasivayam Chinnaiya , Thamaraiselvi Kaliannan , Yamuna Rangaiya T.
Published: November 2006

The ability of ‘waste’ Fe(III)/Cr(III) hydroxide to adsorb paraquat has been investigated. Effects of contact time, initial concentration and pH, adsorption capacity and desorption have been studied. Adsorption followed a first‐order expression. The adsorption rate constant decreased from 1–84 to 0–50 min−1 with the increase of paraquat concentration from 10 to 40 mg litre−1. Adsorption obeyed the Freundlich isotherm and the K1 value was found to be 0.1995. A maximum removal of 93% was attained at pH 1204. Desorption with water occurred to the extent of 39% indicating that physical sorption was partly responsible in the adsorption process.
Fungicidal activity of three putrescine analogues
Authors: Havis Neil D. , Walters Dale R. , Martin William P. , Cook Fiona M. , Robins David J.
Published: November 2006

The synthetic putrescine analogues (E)‐N,N,N′,N′‐tetraethyl‐l,4‐diaminobut‐2‐ene(E‐TED), the (Z)‐isomer (Z‐TED) and (E)‐N,N‐dimethyl‐1,4‐diaminobut‐2‐ene(E‐DMD) were prepared as their salts, and controlled five important crop pathogens (Erysiphe graminis DC f.sp. hordei Marchal, Uromyces viciae‐fabae (Pers.) Schroet, Botrytis fabae Sardina, Podosphaera leucotricha (Ell. & Ev.) Salm. and Phytophthora infestans (Mont.) De Bary). E‐TED was also effective in vitro, with growth of P. infestans and Pyrenophora avenae Ito & Kuribay completely inhibited at 1800 and 360 mg litre−1 respectively. When P. avence was grown in the presence of 180 mg E‐TED litre−1, there were significant reducuons in putrescine and spermidine concentrations (58% and 35% respectively). An apparent increase in ornithine decarboxylase activity and a decrease in S‐adenosylmethionine decarboxylase activity in P. avenae exposed to E‐TED at 36 mg litre−1 were not statistically significant. Diamine oxidase activity remained unchanged in fungal tissue exposed to E‐TED.
Exploration of glycoprotein structures: Sequences and consequences
Authors: Kent Paul W.
Published: November 2006

The vast expansion in our knowledge of the detailed molecular structure of many glycoproteins has been achieved by purpose‐designed methodologies. In this review, principal experimental methods for gaining fundamental evidence are assessed with respect to well‐known iV‐glycoproteins (e.g. ribonucleases), 0,N‐glycoproteins (e.g. glycophorin A) and O‐glycoproteins (e.g. submaxiilary gland mucins and some sulfated forms). Relevant properties of N‐carbohydrate‐peptide links (N‐acetylglucosaminyl‐asparagine) and O‐linkages (N‐acetylgalac‐tosaminyl‐Thr (or ‐Ser)) are reviewed and the classification and structure of more elaborate glycoproteins is outlined.

Key reactions, both chemical and enzymic, effect the cleavage of N‐ and O‐oligosaccharide side‐chains from core protein, and subsequent calibrated chromatographic analysis can permit the identification of certain oligosaccharide groupings characteristic of glycoforms (families of glycoproteins different only in the oligosaccharide chain lengths and bond structures).

Basic sequencing of individual oligosaccharides is generally achieved by chemical methods (e.g. methylation analysis, degradation with periodate) and by the action of well‐characterised specific exo‐ and endoglycosidases. Degradation of a glycoprotein chemically (e.g. by cyanogen bromide) or enzymically by endopeptidases to glycopeptides provides means for locating oligosaccharide position(s) on the core protein.

The presence of O‐sulfate ester groups on oligosaccharide side‐chains presents further challenging problems for sequencing investigations.

Some correlations between oligosaccharide sequences and biological function are considered. While, in the main, the best‐known glycoprotein structures are for those of mammalian origin (e.g. Igs), evidence points to other areas of interest in plants (especially yeasts), invertebrates and micro‐organisms. Allusion is made to current comparative and fundamental physico‐chemical techniques, especially gel permeation chromatography, membrane‐transfer, FAB‐MS and NMR (NOE, COSY, etc.).
The effect of three different pesticides on soil protozoan activity
Authors: Ekelund Flemming , Rønn Regin , Christensen Søren
Published: November 2006

Three pesticides, dimethoate, pirimicarb and fenpropimorph, had a negative impact on the colonization of a sterilized soil by a natural population of soil protozoa. Fenpropimorph has an effect at the lowest concentration applied; 25 mg litre−1. Dimethoate reduced the soil respiration significantly for about 10 days after application. In single species cultures of soil protozoa in liquid media, a flagellate Cercomonas sp., was a better test organism than a ciliate, Colpoda sp., or an amoeba, Acanthamoeba sp., with respect to interpretation of dose‐response curves and ease of observation.
Mercury(II) ion‐promoted hydrolysis of some organophosphorus pesticides
Authors: Wan Hai Bin , Wong Ming Keong , Mok Chup Yew
Published: November 2006

The promotion of hydrolysis of some organophosphorus pesticides by mercury(II) ion was studied. The presence of mercuric chloride at 20 mg litre−1 increased the initial hydrolysis rates of malathion, fenitrothion, fenthion and parathion‐methyl in pH 5.5 buffer by two to three orders of magnitude. The hydrolysis was found to be first order with respect to both mercury(II) ion and the pesticide. The main hydrolysis product was 3‐methyl‐4‐nitrophenol for fenitrothion, and 4‐nitrophenol for parathion‐methyl. It is postulated that the reaction involves the formation of a 1:1 complex and a very slow regeneration of the mercury(II) ion from the reacted complex. Mercury(II) ion had little effect on the organophosphorus pesticide dichlorvos.
Behaviour of an alginate‐kaolin based controlled‐release formulation of the herbicide thiobencarb in simulated ecosystems
Authors: Gan Jianying , Hussain Manzoor , Rathor Nasir M.
Published: November 2006

An alginate‐kaolin based controlled‐release formulation of the herbicide thiobencarb, TCR‐1, was prepared. The distribution, bioaccumulation and persistence of thiobencarb from this formulation were compared to those from a commercial granular formulation, 10 G, in flooded paddy soil under controlled conditions and in simulated aquatic systems and rice paddy/fish systems under greenhouse conditions. Persistence of the total residues and thiobencarb parent increased significantly in the soil treated with TCR‐1, and at the end of a 49‐day incubation 32.5% of the applied herbicide was recovered as the parent from the soil treated with TCR‐1, compared to only 15.2% from the soil treated with 10 G. Slower release into water and less accumulation in fish tissues were found in the simulated aquatic system treated with TCR‐1. A lower concentration was detected in the paddy water in the simulated rice paddy/fish system treated with TCR‐1 over the duration of a 66‐day greenhouse experiment. Fish and rice plants accumulated less residues from the system treated with TCR‐1 than from that with commercial formulation 10 G. The overall results indicated that the persistence of thiobencarb in the controlled‐release formulation was prolonged in water and soil, and the potential impact on non‐target components such as rice plants and fish was concurrently reduced.
Dissipation of tralkoxydim herbicide from wheat crop and soil under sub‐tropical conditions
Authors: Srivastava Anjana , Gupta K. C. , Singh Govindra
Published: November 2006

The persistence of tralkoxydim herbicide in wheat crop and in soil was evaluated under Indian sub‐tropical field conditions at two application rates (400 g a.i ha −1 and 800 g a.i ha −1). At 400 g a.i ha −1, tralkoxydim persisted up to 28 days in soil but became non‐detectable only after 45 days in the crop. However, at 800 g a.i ha −1, tralkoxydim residues persisted for 45 days in both soil and crop. The dissipation of the herbicide from both soil and crop appeared to occur in two phases at both rates of application. Each phase followed first‐order kinetics. The values of DT50 and DT90 for both soil and crop are reported.
Characterization of residues in soybeans grown in soil treated with 1,3‐dichloropropene soil fumigant
Authors: Barnekow David E. , Brown Stephen M. , Byrne Sandra L. , Hamburg Arlene W. , Huskin Mike A. , Leisure Andrea M.
Published: November 2006

The metabolism of cis‐ and trans‐1,3‐dichloropropene (1,3‐D) was studied in soybean plants grown in soil treated 24 days prior to planting with [U‐14C]E‐ and Z‐1,3‐dichloropropene at 380 liters ha−1. Isolation and identification of the 14C residue from soybean plants at 84 days (forage) and 176 days (mature) after application showed that no 1,3‐dichloropropene or its putative metabolites, 3‐chloroallyl alcohol and 3‐chloroacrylic acid, could be detected in any of the tissues. The components of the 14C residue included major plant constituents (i.e. fatty acids, protein, pigments, organic acids, sucrose and other carbohydrates, and lignin).
Detection of cyclodiene insecticide resistance‐associated mutations by single‐stranded conformational polymorphism analysis
Authors: Coustau Christine , ffrench‐Constant Richard
Published: November 2006

Cyclodiene insecticide resistance is associated with replacements of a single amino acid within the putative lining of a δ‐aminobutyric acid (GABA)‐gated chloride ion channel gene Resistance to dieldrin (Rdl). Only two resistance‐associated amino acid replacements have been identified; alanine to serine in Drosophila melanogaster, D. simulans, Aedes aegypti, and Tribolium castaneum and alanine to glycine as a second allele in D. simulans. Here we report that single stranded conformational polymorphism (SSCP) analysis of genomic DNA, amplified by the polymerase chain reaction (PCR) for exon 7 of the Rdl gene, can be used to genotype strains or individuals of all of these insects. This technique also appears simultaneously to distinguish between D. melanogaster and D. simulans, sibling species only reliably identifiable by examination of male genitalia. The relative advantages of this genotyping technique against other PCR‐mediated techniques in monitoring for insecticide resistance are discussed.
Steady‐state and transient analysis of integument penetration by insecticides
Authors: Salgado Vincent L.
Published: November 2006

Insecticide penetration studies are usually done by applying a finite dose of material to a finite area of the integument in a solvent, such as acetone, that evaporates very quickly. The time‐course of penetration is then measured either as the buildup of material inside the insect or as the decline of material recoverable in a surface wash. Pharmacokinetic models are often used to describe such experiments, but identical models can be formulated from diffusion theory. Diffusion theory was applied to obtain equations that describe the steady‐state behavior of a single‐layer integument with partitioning between integument and solutions, and a double‐layer integument with partitioning between layers and between each layer and the adjacent solution. The steady‐state flux equations for both models were first‐order, and it was shown that this would be the case for steady‐state flux through any number of layers.

The steady‐state analysis has two limitations. First, the assumption of a steady state implies that the concentration gradient across each layer of the integument is linear, and that this could not occur instantaneously. Second, the analysis assumes that material diffuses from a pool on the surface at some external concentration, whereas, ideally, it is applied as a plane source of infinite concentration. If the steady‐state assumption is rejected, the diffusion equation can be solved exactly, using Green's function, for diffusion of a topically applied dose across the integument modeled as a homogeneous plate, if the concentration at the internal face is assumed to remain zero. An analytical expression is obtained for concentration as a function of time and position in the integument, and from it are calculated flux into the insect and disappearance of material recoverable in a solvent wash, where material is assumed to be recoverable to an arbitrary depth. For small values of recovery depth, recovery falls precipitously following application, then progressively more slowly as the experiment proceeds. This phenomenon has been seen in much published data, and is explained adequately for the first time by the theory presented here. Predicted flux into the insect rises with a delay and then falls, but its fall is not exponential, as is often assumed. Peak flux is predicted to be directly related to the diffusion coeficient. The impact of these results on the design of penetration experiments is discussed.
Foliar absorption of some glyphosate formulations and their efficacy on plants
Authors: Lærke Poul E. , Streibig Jens C.
Published: November 2006

Uptake of various doses (0.27–4.06 g litre−1) of glyphosate acid formulated with various concentrations (0.27–5.42 g litre−1) of two polyethoxylated alcohol surfactants ‘Genapol’ T‐150, ‘Genapol’ T‐250) in wheat (Triticum aestivum L. cv. Ralle) 24 h after application was studied. Both surfactants greatly enhanced glyphosate uptake at concentrations up to 1.35 g litre−1. Uptake could be slightly further improved by ‘Genapol’ T‐150 up to 5.42 g litre−1 while ‘Genapol’ T‐250 at this high concentration antagonized uptake a little. Uptake of glyphosate‐monoammonium formulated with a quaternary ammonium surfactant (‘Trimao’ (8PO)) in wheat and white mustard (Sinapis alba L. cv. Alba) was also studied. Uptake of glyphosate‐monoammonium in wheat was enhanced at surfactant concentrations up to 1.35 g litre−1. Beyond this concentration uptake continued to increase slightly but not significantly. Generally, glyphosatemonoammonium formulated with ‘Trimao’ (8PO) was not taken up as extensively by mustard as by wheat, and the optimum surfactant concentration is probably higher on mustard. The optimal combinations of surfactant concentration and glyphosate dose based on uptake 24 h after application were used in a time‐course study.

Results from uptake studies were compared with the efficacy of similar formulations on wheat. The surfactant concentration range which gave the most pronounced effect on glyphosate uptake was found to be similar (0–1 g litre−1) in both studies. However, the surfactant concentration providing maximum herbicide uptake was found to be higher in the uptake study compared to the surfactant concentration providing optimal efficacy in the dose‐response experiments. A dose rate of 0.5 g litre−1 of ‘Tween’ 20 (sorbitan monolaurate surfactant) improved efficacy of a formulation with an optimal mix of glyphosate‐monoammonium and ‘Trimao’ (8PO). Ammonium sulfate (5.0 g litre−1) did not improve this formulation further.
Investigation on the transformation of fluchloralin by soil fungi: Identification of some metabolites
Authors: Guha Prabir K. , Saha Jayanta , Chaudhuri Subhendu , Pal Srikumar , Bhattacharyya Anjan , Adityachaudhury Narayan
Published: November 2006

Fluchloralin [N‐(2‐chloroethyl)‐α,α,α,‐trifluoro‐2,6‐dinitro‐N‐propyl‐p‐toluidine] was transformed by two common soil fungi, Aspergillus flavus Link and Fusarium solani (Mart.) Sacc. in pure culture. The fungi were isolated from enrichment cultures of an analogous herbicidal compound, pendimethalin [N‐(1‐ethylpropyl)‐2,6‐dinitro‐3,4‐xylidine)]. Transformation of fluchloralin by these fungi resulted in the formation of several metabolites, 13 of which were identified. Besides the known mechanisms of microbial transformation of dinitroanilines, methylation of the anilino nitrogen and direct elimination of a nitro group at 2 position from the aromatic ring without any further substitution were also observed.
Nerve insensitivity resistance to cypermethrin in larvae of the tobacco budworm Heliothis virescens from USA cotton field populations
Authors: McCaffery Alan R. , Holloway Jonathan W. , Gladwell Richard T.
Published: November 2006

Spontaneous neuronal activity was recorded from the peripheral nerves of third‐instar larvae of strains of Heliothis virescens (F.) obtained directly from cotton fields in the USA. Following a control period the preparations were exposed to increasing concentrations of cis‐cypermethrin in a cumulative dose‐response assay. A positive response was defined as an increase of at least five‐fold in the rate of neuronal activity over that seen during the control period. Up to 35 individuals of each strain were assayed and the responses used to construct a phenotypic profile categorising the individuals from nerve‐susceptible to highly nerve‐insensitive. An EC50 for the action of cis‐cypermethrin was also obtained. There was a positive, significant correlation between non‐synergisable resistance to cypermethrin and nerve insensitivity as defined in the neurophysiological assay. It was shown that nerve insensitivity to cypermethrin increased throughout the cotton‐growing season.
Evaluation of different formulations of deltamethrin in comparison with permethrin for impregnation of netting
Authors: Elissa Nohal , Curtis Christopher F.
Published: November 2006

Five formulations of deltamethrin and one of permethrin were impregnated into cotton and nylon netting and tested for their efficacy and persistence in killing Anopheles gambiae Giles which were attempting to penetrate the netting in search of blood meals. Emulsifiable concentrates persisted better than wettable powders of deltamethrin, and all the deltamethrin formulations performed better than permethrin, even though the latter was applied at an eight times higher dose. The insecticidal effect of both compounds persisted better on nylon than on cotton; it was adversely affected by repeated washing.
Extended summary agriculture and bio‐organic groups of the RSC and the SCI pesticides group symposium chemical aspects of biological control. The production of chemicals by biological control agents
Authors: Powell Keith A.
Published: November 2006

The following extended summary is based on a paper presented at the above meeting organised by R. L. Richards and L. G. Copping on behalf of the Agriculture and Bio‐organic Groups of the RSC and the SCI Pesticide Group, held on 21 November 1994 at Brighton, UK. The summary published here is entirely the responsibility of the author and does not reflect the views of the Editorial Board of Pesticide Science.
In‐vivo effects of 2,4‐D and atrazine on cytochrome P‐450 and insecticide toxicity in southern armyworm (Spodoptera eridania) larvae
Authors: Kao L. M. , Wilkinson C. F. , Brattsten L. B.
Published: November 2006

After feeding 2,4‐D or atrazine in a diet to southern armyworm (Spodoptera eridania Cram.) larvae for three days, the effect on total content and activities of cytochrome P450 and on insecticide toxicity were determined. Both 2,4‐D and atrazine induced cytochrome P450‐catalyzed aldrin epoxidation (AE) and methoxyresorufin O‐demethylatin (MROD). The 2,4‐D was a more potent inducer for total cytochrome P450 content, whereas atrazine disproportionately increased AE. Both compounds increased MROD significantly. The apparent kinetic characteristics of AE indicates that 2,4‐D and atrazine induced similar P450 isozymes (Km 8.78 and 7.80 μM, respectively), which may differ from the constitutive isozyme (Km 3.14 μM). The 2,4‐D‐induced cytochrome P450 contributed to decreased carbaryl and permethrin toxicity, whereas the atrazine‐induced cytochrome P450 caused decreased parathion and permethrin toxicity. The carbaryl toxicity correlated directly with 2,4‐D‐induced total P450 content and activities but not with atrazine‐induced changes. The 2,4‐D and atrazine also induced nonspecific esterase activity which may contribute to permethrin detoxification.
Development and characteristics of resistance in the susceptible who/srs house fly (Musca domestica) strain subjected to selection with beta‐cypermethrin
Authors: Pap László , Tóth Andrea
Published: November 2006

The standard reference WHO/SRS house fly (Musca domestica L.) strain was selected with beta‐cypermethrin (‚Chinmix’︁) by topical application for 25 consecutive generations. By the F25 generation the LD50 (expressed as ng per fly) increased to 164.9 × and 190.2 × initial values in the female and male flies, respectively, of the selected strain (CHXSEL).

Developing rates and patterns of resistance seemed to be similar in both sexes and showed four characteristic phases: I. stagnant, II. quickly rising, III. slowly increasing and IV. plateau.

Due to high mortality and low fertility of survivors after F25 the selecting dosages could not be increased further, indicating that a selection limit had been reached.

Upon termination of selection pressure the resistance reverted almost completely in the NOSEL substrain. The LD50 decreased continuously and by the F60 generation the resistance ratios (RR) were only 6‐9 and 10‐2 in the female and male flies, respectively.

Synergist studies with different metabolic inhibitors, SKF‐525a, piperonyl butoxide, 1‐naphthyl N‐propylcarbamate and NIA‐16388 suggested that both enhanced oxidase and esterase activity would contribute to the resistance of the CHXSEL strain. Moreover the analysis of the cross‐resistance pattern among pyrethroids makes the presence of a nerve insensitivity factor likely. The pattern of cross‐resistance within and outside the pyrethroid group is discussed in detail. The relationship of contributing resistance mechanism(s) to similarities of chemical structures is also discussed.
Generation of end‐group information from polyethers by matrix‐assisted laser desorption/ionisation collision‐induced dissociation mass spectrometry
Authors: Jackson Anthony T. , Green Martin R. , Bateman Robert H.
Published: November 2006

A series of polyethers, namely poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), poly(butylene glycol) (PBG) and poly(tetramethylene glycol) (PTMeG), has been characterised by means of matrix‐assisted laser desorption/ionisation collision‐induced dissociation (MALDI‐CID) using a hybrid sector orthogonal‐time‐of‐flight (TOF) instrument. The data indicate that this technique can be used to generate information about the end‐group functionality of these polymers, including in some cases information about branching of the alkyl chains of the initiating groups. Proposals are made for the fragmentation pathways for these polymers. Copyright © 2006 John Wiley & Sons, Ltd.
Amidons Lintnérisés Etudes chromatographique et enzymatique des résidus insolubles provenant de l'hydrolyse chlorhydrique d'amidons de céréales, en particulier de maïs cireux
Authors: Robin Par J. P. , Mercier C. , Duprat F. , Charbonniǵre R. , Guilbot A.
Published: November 2006

Lintnerized Starches. Chromatographic and Enzymatic Studies of Insoluble Residues from Acid Hydrolysis of Various Cereal Starches, Particularly Waxy Maize Starch. Native cereal starches, particularly waxy maize starch, have been carefully hydrolyzed at 35°C with hydrochloric acid (2,2‐N) in heterogeneous phase.

Observation of the course of hydrolysis as a function of time makes it possible to classify the starches according to their acid lability. The kinetic values distinctly reveal two phases, i.e. a fast hydrolysis of the amorphous fraction and a slower degradation of the crystalline starch grain fraction. This observation was confirmed by X‐ray diffractometric patterns. The hydrolysis speed of acid resistant fractions seems to become slower as the apparent amylose ratio increases.

The change in the macromolecular structure of the obtained granular residues or “lintnerized” starches as a function of time was examined after aqueous solubilization by means of gel chromatography using a calibrated Sephadex G‐50 column. Lintnerization causes a decrease in the apparent DP of the chains of the starch residues and two subgroups with apparent DP 13 and 25 appear rapidly. These DP are unchanging with time of acid treatment.

The chromatographic and enzymatic studies of lintnerized starches were performed directly and after successive enzymatic digests with pullulanase and ß‐amylase. After debranching of solubilized residues with pullulanase and gel chromatography a linear chain subgroup of DP 15–20 appears. This one is in fact composed of two subgroups: one more important with a DP 13, the other broad distribution with a DP 15–25. The comparison with the subgroups observed before debranching shows that a main part of the initial subgroup of DP 25 could be considered as formed with singly branched chains. Furthermore a small proportion of pullulanase resistant ß‐limit dextrins was obtained.

The obtained results permits one to suggest a new model for the structure of waxy maize amylopectin. On the basis of this model the differences in structure existing between the various starches are discussed and the results are compared with those reported elsewhere for potato starch. A parallelism between crystalline patterns of native starches and the amylopectin structure, particularly its branching degree, is observed.
Radiolyse von Stärke Beitrag zur quantitativen Bestimmung einiger Radiolyseprodukte in Kartoffelstärke und Weizenmehl
Authors: Scherz H.
Published: November 2006

Radiolysis of Starch. A Contribution to Quantitative Determination of Several Radiolysis Products in Potato Starch and Wheat Flour. The amounts of formed desoxy‐compounds, which produce malonic dialdehyde during HI O4‐oxydation, as well as that of ω‐hydroxymaltol have been determined in irradiated potato starch and irradiated wheat flour in dependence on irradiation doses. With pure potato starch, G‐values*) of 0.03–0.04 for water soluble desoxy‐compounds and such ones of 0.02 for insoluble desoxy‐compounds were obtained. G‐values of desoxy‐compounds in an ethyl acetate‐acetone‐water extract (4: 5: 1 v/v) of irradiated potato starch and irradiated wheat flour showed a ratio of about 3: 1. When aqueous potato starch sols are irradiated desoxygroups in the high‐molecular starch molecule will also be found (in N2O atmosphere: G‐values around 0.3).

With ω‐hydroxymaltol it became apparent that the main part of this compound is formed after irradiation during storage. With pure potato starch G‐values around 0.015–0.02 were determined after 10 days of storage. When this material is heated after irradiation an increase of the hydroxymaltol content (G‐values: 0.025) is to be found.

In the non‐irradiated materials traces of desoxy‐compounds as well as ω‐hydroxymaltol were found.
Properties of Starch Obtained from Potato Tubers Influenced by Various Temperatures
Authors: Golachowski A.
Published: November 2006

The properties of starch separated from potato tubers were studied regarding the following storage temperatures: +20 °C, +8 °C, +4 °C and 0 °C. The study included also potato tubers having been frozen, thawed and refrozen as well as potato tubers before storage. Starch separated from the stored potato tubers showed differences in chemical composition, reducing power, granularity, whiteness and viscosity as well as gelatinization temperatures in comparison with the starch separated from potato tubers before storage. Quantity and direction of the changes within starch properties depended on storage temperatures. The smallest changes in the properties were observed during potato storage at +4 °C and +8 °C.