bluuebunny/crossref_metadata_2025 huggingface dataset:
The pyrethrins and related compounds. Part XXXVII. synthesis and insecticidal properties of new 1‐aryl‐1‐(3‐arylpropyl and ‐propenyl)cyclopropanes (non‐ester pyrethroids)
Authors: Farnham Andrew W. , Ifill Anderson , Janes Norman F. , Javed Tariq , Khambay Bhupinder P. S.
Published: November 2006

New routes to the title compounds, involving improved conditions for the cyclopropanation, and a new method of constructing the central three‐carbon unit (based on the coupling of a Grignard reagent with an allylic acetate) give access to products for which the previously reported route was not satisfactory. For the new route, a synthesis of 5‐bromo‐2‐fluoro‐diphenyl ether was developed. Previously deduced relationships between structure and insecticidal activity apply for the new compounds: alkenes are generally more active than corresponding alkanes; substitution at the 3‐ or 4‐position (but not the 2‐) of the 1‐aryl group can enhance activity. In addition, some fluorine‐containing substituents lead to high activity.
Designing, implementing and servicing an insecticide resistance management strategy
Authors: Forrester Neil W.
Published: November 2006

Drawing on the experience gained in the management of resistance in Heliothis armigera in Australia, the successive stages of designing, setting up and monitoring an insecticide resistance management (I R M) programme are discussed, along with the problems that may have to be overcome in order to achieve success. While individual strategies will inevitably differ, the Australian experience should give valuable information for the setting up of IRM programmes worldwide.
Determination of tau‐fluvalinate residues in honey
Authors: Barbina Maria Taccheo , De Paoli Mauro , Valentino Alan
Published: November 2006

A capillary column gas chromatographic method is described for the determination of tau‐fluvalinate in honey samples. The method involves solid phase extraction of the sample with two RP C‐8 cartridges in series, purification of the extract, if necessary, on a silica cartridge, and detection of the active ingredient with an electron capture detector. The method is rapid and overcomes the problem of emulsion formation in liquid/liquid partition often found in traditional systems. The detection limit in actual samples is 0.01 mg kg−1 and mean recoveries for fortified samples prepared with or without clean‐up are greater than 85%.
Relation between volatility rating and composition of phenoxy herbicide ester formulations
Authors: Noble Alan , Hamilton Denis J.
Published: November 2006

A CIPAC/AOAC test with tomato plants is used to specify the volatility ratings of herbicide ester formulations. This work compares the tomato plant test with an alternative chemical one. The concentrations of esters and the effective molecular weight and density of each formulation were used with the ester vapour pressures to calculate its herbicide vapour pressure as complete, and evaporated formulations. The range was from 28.8 mPa (at 257deg;C) for a mixture of 2,4–D esters to 0–07 mPa (at 25°C) for a 2,4,5–T‐(iso‐octyl) formulation, as complete formulations, and 35‐5 and 0–16 mPa (at 25°C) as evaporated ones. A value of 0–6 mPa (at 25°C) was selected on the basis of the tomato plant test as the cut‐off area for low‐volatile esters and is recommended to be included in specifications for herbicide esters. Formulations with a herbicide vapour pressure above 3.3 mPa (at 25°C) are high‐volatile ones according to the tomato plant test, while between 0–6–3.3 mPa (at 25°C) is a borderline region where the test gives mixed results. Levels of 2,4–D‐ethyl and methyl were added to pure 2–ethylhexyl esters of 2,4–D and a 2,4,5–T‐(iso‐octyl) formulation to find what level of contamination would change the rating of these esters from low to high volatile. Formulations of 2,4–D‐(iso‐octyl) should not contain more than 11 g litre−1 2,4–D as methyl ester or 2.0 g litre−1 2,4–D as ethyl ester. Formulations of 2,4,5–T‐(iso‐octyl) should not contain more than 26 g litre−1 2,4–D as methyl ester or 4.7g litre−1 2,4–D as ethyl ester.
The effect of selected uv absorber compounds on the photodegradation of pyrethroid insecticides applied to cotton fabric screens
Authors: Hussain Manzoor , Perschke H. , Kutscher R.
Published: November 2006

UV absorber compounds were tested to reduce the photolytic decomposition of deltamethrin, applied to 100 % cotton fabric, to be used as a target screen for tsetse fly control. In the absence of UV absorbers, over 90% of deltamethrin was degraded after 6 h irradiation under an Osram UV‐sun radiation lamp (equivalent to 96 h sunlight) at 35(±1)°C. The degree of protection increased with increase in the proportion of the U V absorber compound. With a mixture of 2,4‐dihydroxybenzophenone (I) and deltamethrin (3 + 1, by mass) 7% of deltamethrin was degraded. Similarly, I protected alpha‐cypermethrin and cyfluthrin against photolysis, I and 2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid (IV) both protected deltamethrin from “Glossinex 200” SC formulation against photolysis, but I was more effective than IV.
Mode of action of insecticidal dihydropyrazoles: Selective block of impulse generation in sensory nerves
Authors: Salgado Vincent L.
Published: November 2006

When injected into cockroaches (Periplaneta americana), dihydropyrazoles (pyrazolines), e.g. RH 3421, methyl 1‐(N‐(α,α,α‐trifluoro‐p‐tolyl)carbamoyl‐3‐(4‐chlorophenyl)‐4‐methyl‐2‐pyrazolin‐4‐ylcarboxylate, caused incoordination, followed by prostration and violent tremors. After several hours, prostrate cockroaches became very still, appearing paralyzed, but for several days they retained the ability to produce violent tremors when physically disturbed. The paralysis was associated with block of spontaneous activity in sensory nerves of cockroaches, tobacco hornworm larvae (Manduca sexta) and housefly larvae (Musca domestica). Block of spontaneous central nervous system activity was also seen in some cases.

Current‐clamp experiments on the cell body of the crayfish slowly‐adapting stretch receptor neuron revealed that spike initiation in response to injected current was blocked by dihydropyrazoles, with no change in resting potential or input resistance, suggesting that the sodium current was suppressed. Hyperpolarization of blocked stretch receptors could reverse block, and crayfish giant axons, which were not normally sensitive to block by dihydropyrazoles, were rendered sensitive when artificially depolarized by elevation of extracellular potassium ion concentration, leading to the conclusion that the block of sodium current was strongly voltage dependent. The proposed mode of action, while similar to that of local anesthetics, class I anticonvulsants and class I antiarrhythmics, is novel for an insecticide.
A new fungicide—HDE and its application in controlling wilt disease of cucurbits
Authors: Li Zhichang , Liu Chiqing
Published: November 2006

Homodemycine (HDE) is a copper complex of several different amino acids. It is a highly effective, low‐toxic and non‐residual fungicide. Toxicological tests have shown this organo‐copper fungicide to have an oral LD50 (Rats) of 1380 mg kg−1, and it is not mutagenic (Ames negative). Field trials over several seasons have shown crop growth stimulation and yield increases in addition to control of cucurbit wilt and other diseases. This paper summarises trials with HDE for the control of cucurbit wilt.
Fate and persistence of residues on wheat used to explain efficacy differences between deltamethrin suspension concentrate and emulsifiable concentrate formulations
Authors: Hill Bernard D. , Inaba Dan J.
Published: November 2006

To help explain the increased residual activity of a deltamethrin suspension concentrate (SC) formulation against grasshoppers, the persistence, location and nature of residues from the SC and an emulsifiable concentrate (EC) formulation have been compared. Wheat plants were sprayed in a cabinet sprayer at 7.6 g ha−1 for the EC and 5.6 g ha−1 for the SC, then weathered outdoors for 16 days. With the SC formulation, residues were more persistent, more residues were located on the exterior of the leaves, and less deltamethrin was converted to inactive isomers. Eight days after spraying, the exterior deltamethrin residues were 0.13 μg plant−1 from the SC versus 0.06 μg plant−1 from the EC. Thus, more residual deltamethrin is available to grasshoppers with the SC formulation.
Synthesis and fungicidal activity of phenanthridinotriazines: A structure–activity relationship study
Authors: Coghlan Michael J. , Arnold Wendell R. , Caley Blake A.
Published: November 2006

A series of analogous tetracyclic 1, 12b‐dihydro‐4H‐1,2,4‐triazino[4,3‐f] phenanthridines and 4H,12bH‐1,2,5‐oxadiazino[5,6‐f]phenanthridines was prepared and tested for control of Erysiphe graminis f. sp. tritici (the causal agent of powdery mildew in wheat). Several analogs showed exceptional activity at doses as low as 6.25 mg litre−1 with substituted analogs VII, X, and XIV being the most potent. Singly substituted tetrahydrotriazinyl or oxadiazenyl rings with lipophilic aromatic components appeared to be the key requirements for optimal powdery mildew control. Substitution of the heterocyclic ring with multiple groups attenuated activity.
The effectiveness of eleven sterol biosynthesis‐inhibiting fungicides against the take‐all fungus, Gaeumannomyces graminis var. tritici, in relation to their physical properties
Authors: Bateman Geoffrey L. , Nicholls Peter H. , Chamberlain Keith
Published: November 2006

Eleven sterol biosynthesis‐inhibiting fungicides were compared in experiments to determine the physico‐chemical properties required for most effective control of take‐all by soil treatment. All were active in agar culture against an isolate of the pathogen which causes take‐all, Gaeumannomyces grammis var. tritici, with prochloraz being the most toxic (EC50 0.02 μg ml−1) and PP 969 the least (EC50 0.44 μg ml−1). Penconazole and PP 969 had vapour activity against the fungus in further bioassays on agar. In soil in pots, the most strongly lipophilic compound, buthiobate, was ineffective against take‐all in wheat; triadimenol was most effective and, like flutriafol, nuarimol and PP 969, retained some effectiveness after 12 weeks in soil. PP 969, unlike penconazole or nuarimol, was effective in soil treated unevenly by mixing the fungicides in layers. PP 969 is relatively polar, and it is suggested that this property, allowing redistribution in soil water rather than as vapour, outweighed its poor intrinsic toxicity. The ideal soil‐treatment fungicide should therefore be polar and also have good intrinsic activity and moderate persistence. None of the compounds tested had all these properties.
An ultrastructural study of the effect of metalaxyl on Phytophthora capsici infected stems of Capsicum annuum
Authors: Hwang Byung Kook , Ebrahim‐Nesbat Firous , Ibenthal Wolf‐Dieter , Heitefuss Rudolf
Published: November 2006

Stems of pepper seedlings were inoculated with zoospores of Phytophthora capsici 18 h after a soil‐drench with metalaxyl solution (5 μg ml−1) or water. Infected stem tissues were examined by electron microscopy 24 h after inoculation. Compared with untreated controls, in which the fungal cells were generally normal in shape and ultrastructure, the most conspicuous effects of metalaxyl treatment on the fungal ultrastructure in the stem tissue were an abnormal shrinking of the fungal cell, a separation of the plasma membrane from the hyphal wall, a peculiar invagination and breakdown of the plasma membrane, the presence of vesicles in the invaginated spaces and within the damaged fungal cells, and an indistinct structure of cell organelles. In metalaxyl‐treated stems, an electron‐dense material was apposed in those sites of the host cell wall in most intimate contact with the fungal cell wall, indicating that the deposition of these substances from the host cell walls may function as a plant defence reaction to the fungus, whereas in untreated controls, the dark‐stained host cytoplasm did not aggregate around the sites of fungal contact. The haustorium was encased by the extra‐haustorial matrix in treated stems. These results suggest that metalaxyl treatment not only changes the fine structure of P. capsici, but may also induce the plant defence reaction.
Rationalisation of the mass spectrometric and gas chromatographic behaviour of organophosphorus pesticides: Part 1–substituted phenyl phosphorothioates
Authors: Wilkins John P. G.
Published: November 2006

The mass spectrometric and gas chromatographic behaviour of a series of O,O‐dialkyl O‐(substituted phenyl) phosphorothioates, and some related compounds is reported. Several of these compounds are widely used as pesticides. Appraisal of these data has permitted an increased understanding of the influence of phenyl substituents on the appearance of the mass spectra of these compounds. In particular, the nature and extent of mass spectrometric ortho effects, which are associated with weak molecular ion intensity, and/or the generation of rearrangement ions are reported. Examples in which an understanding of these effects has been helpful in the identification of related compounds, such as technical impurities and degradation products, are given. Published mass spectrometric data for some of these compounds are critically appraised.
Herbicides inhibiting branched‐chain amino acid biosynthesis
Authors: Moberg William K. , Cross Barrington
Published: November 2006

Herbicides inhibiting branched‐chain amino acid biosynthesis represent a signal advance in crop protection chemistry, with implications for both practical weed control and basic agricultural science. In practical terms, at least 20 different active ingredients are currently marketed or are in development, and more may be expected. They offer selectivity in virtually every major crop, unprecedented low use rates, and inherently selective toxicity to plants. In scientific terms, the research behind these compounds shows modern agricultural chemistry at its best. Synthesis has been integrated with other disciplines to understand and rapidly optimize properties. In the process, basic knowledge has been gained in chemistry, biochemistry, and strategies for finding new agrochemicals.

This issue provides the first unified, interdisciplinary overview of the three major classes of inhibitors–sulfonylureas, imidazolinones, and triazolopyrimidines. The following introductory note explores some implications of this research.
Acetolactate synthase, mechanism of action and its herbicide binding site
Authors: Schloss John V.
Published: November 2006

Several new structurally diverse classes of herbicide, including the sulfonylurea herbicides, act by inhibiting acetolactate synthase, the first common enzyme of branched‐chain amino acid biosynthesis. The interaction of acetolactate synthase isozyme II (ALSII) from Salmonella typhimurium with sulfometuron methyl (SM), a sulfonylurea herbicide, has been used as a paradigm in elucidating the mode of action of these herbicides at the molecular level. A number of different studies have collectively suggested that SM binds to ALSII near thiamine pyrophosphate and flavin adenine dinucleotide (FAD), with its binding site overlapping the second pyruvate (or ketobutyrate) substrate site. Most of SM, however, must be accommodated on ALSII at a site that is not equivalent to substrate or co‐factor binding sites. The identity of this herbicide‐specific site has recently been suggested by the discovery that poxB, the gene for pyruvate oxidase, shares substantial sequence homology with ilvB, ilvG and ilvI, the genes for the large subunits of ALSI, ALSII, and ALSIII, respectively. Unlike ALSII, pyruvate oxidase uses its FAD for normal redox chemistry, and binds one additional co‐factor in vivo, ubiquinone‐40. The latter co‐factor binds to pyruvate oxidase in a spatially and kinetically equivalent way to SM with ALSII, suggesting that the herbicide binding site of ALSII has a common evolutionary heritage with the ubiquinone site of pyruvate oxidase.
Imidazolinone inhibition of acetohydroxyacid synthase in vitro and in vivo
Authors: Stidham Mark A. , Shaner Dale L.
Published: November 2006

Imidazolinone herbicides inhibit the first enzyme of branched‐chain amino acid biosynthesis, acetohydroxyacid synthase. The inhibition of the enzyme in vitro by these herbicides increases with incubation time, but is not irreversible, as deduced by reaction progress curves. In contrast to this result is the apparent irreversible inhibition of the enzyme by these imidazolinones that occurs when the herbicide is applied to intact corn plants. Plants treated with imidazolinone herbicide and then extracted showed dramatically reduced enzyme activity. This effect on extractable enzyme level occurred with several different imidazolinone herbicides in either foliar or soil application. The decrease in extractable enzyme activity could be observed within four hours after treatment. Herbicides other than imidazolinones did not reduce the extractable enzyme level. These findings suggest that the enzyme‐ imidazolinone interaction in vivo may be different from the interaction observed in vitro.
Fungicidal activity of a series of 1‐substituted‐1‐aryl‐2‐triazol‐1‐yl‐ethanols
Authors: Chollet Jean‐François , Bonnemain Jean‐Louis , Miginiac Léone , Rohr Otto
Published: November 2006

Twenty‐four I‐substituted‐I‐aryl‐2‐triazol‐I‐yl‐ethanols were prepared by the reaction between acetylenic, propargylic or allylic organometallics and aryl triazolylmethyl ketones. These were tested for antifungal activity against ten phytopathogenic fungi of different taxonomic classes. EC80 values were determined for the seven most active compounds and for two commercial compounds, hexaconazole and flusilazole. In these tests, the fungicidal activity of the new compounds was generally lower than that of the two reference triazoles except for two products which were more active than hexaconazole and flusilazole against powdery mildew on barley.
Trends in the formulation of pesticides—an overview
Authors: Seaman David
Published: November 2006

The customer increasingly requires safer and more convenient pesticide formulations. Emulsifiable concentrates and wettable powders are nowadays viewed less favourably by farmers and registration authorities. Suspension concentrates are now common and water‐dispersible granules and emulsions in water are receiving increasing attention. Capsule suspensions offer both safer and more effective performance in favourable cases. For convenience the farmer requires multi‐component products, either as mixtures of active ingredients, which might be as suspoemulsions, or with built‐in enhancing surfactants and oils. Seed treatments are now required as aqueous suspensions and the seed is increasingly of interest as an eficient carrier for pesticides. Research into biological control agents sets the difficult challenge of formulating these products as viable organisms. Three examples of developments are described. These are the applications of polymeric surfactants for suspension concentrates and suspoemulsions, studies of enhancement of pesticide uptake with surfactants and developments in microencapsulation.
The structure/physical property relationships of a model water‐dispersible granule
Authors: Bell Gordon A.
Published: November 2006

The particles constituting a water‐dispersible granule are arranged in a structure which determines the physical properties of that formulation. To examine the importance of such structures, four examples were prepared which were significantly different in terms of bonding and porosity. Examination by electron microscopy and mercury porosimetry indicated that granule strength and dispersion properties were determined by a combination of structure and bonding. A compact granule with weak bonds proved to be a suitable structure for fast dispersion and high solid strength.
A rapid method using Ricinus communisfor the estimation of phloem translocation of xenobiotics
Authors: Bromilow Richard H. , Chamberlain Keith , Patil Shantagouda G.
Published: November 2006

A simple and relatively rapid test has been developed that enables the phloem mobility of xenobiotics to be assessed. Compounds are applied by injection of an aqueous solution into the petioles of plants of castor bean (Ricinus communis var. Gibsonii), and phloem sap is collected from two incisions made in the stem below the treated leaves over the period of 2 to 4 h after application. Amounts of compounds in the sap are measured by liquid scintillation counting following thin‐layer chromatography for radio‐labelled samples or by high‐pressure liquid chromatography for non‐radio‐labelled compounds. A semi‐quantitative estimate of mobility in phloem can be obtained from these tests, including an estimate of the potential for long‐distance transport via phloem. Mobilities in phloem measured for 28 compounds, mostly weak acids, are placed within a general framework for understanding the phloem transport of compounds in terms of their physico‐chemical properties. This approach can be used to predict and interpret the behaviour of new compounds from a knowledge of their polarity and acid strength.
Simultaneous determination of clofentezine, fenoxycarb and hexythiazox by HPLC on apples, pears and their pulps
Authors: Bicchi Carlo , D'Amato Angela , Tonutti Ivano , Cantamessa Liliana
Published: November 2006

The simultaneous HPLC determination of clofentezine, fenoxycarb and hexythiazox in apples, pears and their pulps is described. The method is based on a clean‐up procedure carried out on a Seppak C18 cartridge followed by HPLC analysis on an RP‐18 column using acetonitrile + water as mobile phase. Average recoveries were 85.0% for clofentezine, 84.8% for fenoxycarb and 75.6% for hexythiazox on apple matrix; recoveries from pear matrix were in the same range. UV detection limits at 240 nm were 0.07 mg kg−1 for clofentezine, 0.064 mg kg−1 for fenoxycarb and 0.08 mg kg−1 for hexythiazox.
The fate of chlorpyrifos‐methyl in stored wheat: A comparison of a laboratory‐scale experiment with a pilot‐scale treatment
Authors: Matthews Wendy A.
Published: November 2006

An experiment was carried out in which a pilot‐scale treatment of a bulk of grain with chlorpyrifos‐methyl was compared with a laboratory treatment of 1 kilogram of grain with 14C‐radio‐labelled chlorpyrifos‐methyl. The conditions under which the grain was maintained in the laboratory resembled those of the pilot‐scale treatment as closely as possible, with sampling and analysis being carried out at the same time and in a similar manner in both. The results from the two experiments were in general agreement with approximately 60% of the chlorpyrifos‐methyl remaining intact at the end. A satisfactory level of insect control was achieved in the pilot‐scale treatment although it was not possible to assess efficacy in the radiochemical experiment. The use of the radio‐label enabled more information about the fate of the degraded insecticide to be obtained from the laboratory experiment. The majority of this radioactivity comprised a fraction which remained within the grain tissue after solvent extraction. The level of activity in the grain tissues gradually increased with time but its nature is as yet unknown.

The good agreement obtained between the residue profile and the breakdown patterns in both experiments would suggest that such a laboratory‐scale experiment can be a satisfactory model for the situation obtaining in a larger‐scale treatment.
Plant‐growth‐regulating phosphono peptides
Authors: Wieczorek Piotr , Lejczak Barbara , Kaczanowska Malgorzata , Kafarski Pawel
Published: November 2006

Phosphono peptides exhibited plant‐growth‐regulating activity when tested on Lepidium sativum and Cucumis sativus. The studies have provided evidence that the mechanism of action of these compounds may involve the uptake of the phosphono peptides into the plant, intracellular hydrolysis of the peptide bond and release of the P‐terminal aminoalkylphosphonic acid. This acid or its metabolite is then probably responsible for the observed physiological effect.
The kinetics of insecticide action. Part IV: the in‐vivo distribution of pyrethroid insecticides during insect poisoning
Authors: Greenwood Richard , Ford Martyn G. , Peace Edwin A. , Salt David W.
Published: November 2006

The distribution of pyrethroids in insects has been studied using a combination of mathematical modelling and experimental observation. This approach has resulted in the formulation of a physiological model of the pharmaco‐kinetics of cypermethrin applied topically to larvae of Spodoptera littoralis. Development of this model from simpler two‐ and three‐compartment models is described. Simple models, whilst capable of complex behaviour, consider only the average rates and magnitudes of pharmaco‐kinetic processes over whole animals, and cannot account for differences in concentration of insecticide between individual tissues. This can be achieved by using physiological models, but these require more experimental information for their validation. Moreover, unless simplifying assumptions are made, analytical solutions are not feasible for the large number of equations necessary to define such models.

The modelling studies prompted an investigation of (1) in‐vivo binding of insecticide to insect tissues, (2) the sizes of body compartments, and (3) the factors which affect the distribution of toxicant between these compartments. Binding has a marked effect on pharmacokinetic profiles and may result in oscillatory behaviour. During poisoning, the total bound cypermethrin increases proportionally to the cube root of the elapsed time. This results in a rapid rate of increase over early elapsed times (< 3h) which slows to approach a more linear form thereafter. Average sizes for the body compartments of larvae of Spodoptera littoralis Boisd, and the steady‐state distribution of cypermethrin in these compartments are described. Although the haemolymph, which acts as the main distributive phase during poisoning, forms the largest compartment by volume, it has a low affinity for cypermethrin and distribution reaches steady state within 5 min after topical application. The nerve cord (the target tissue), which is the smallest compartment, has the highest steady‐state concentration of cypermethrin. The distribution of cypermethrin in larval tissues is related to the ratios of tissue dry matter to water content.
The determination of residues of 2,4‐D in post‐emergence‐treated triticale
Authors: Cessna Allan J.
Published: November 2006

A gas chromatographic method, using electrolytic conductivity detection, is presented for the determination of 2,4‐0 as its methyl ester in triticale (X Triticosecale Wittmack). The method was used to monitor the dissipation of 2,4‐0 residues in triticale over a growing season at two sites following post‐emergence application of the dimethylamine salt of 2,4‐D at 0.56 kkg ha−1. Initial residues, in the order of30 mg kg−1. on the day afer application (3‐ to 4‐leaf stage of the crop), decreased to non‐detectable levels in the mature straw and seed. Recoveries of 2,4‐D were greater than 90% fiom green tissue fortified at 0.1 mg k−1., and in the order of 75% from seed fortified at 0.05 mg kg−1.
Off‐target deposits and buffer zones required around water for aerial glyphosate applications
Authors: Payne Nicholas J. , Feng Joseph C. , Reynolds Philip E.
Published: November 2006

Off‐target deposit has been quantified from various silvicultural glyphosate application methods and an estimate made of the buffer‐zone widths required around water to protect fish and their invertebrate food species from possible toxicological effects. To overcome the difficulty of estimating different buffer widths to meet the various use conditions encountered, a realistic worst‐case scenario was chosen for small‐drop drift and data were collected accordingly. Three glyphosate application methods were tested, employing a helicopter equipped with a ‘Microfoil’ boom, a ‘Thru Valve Boom’ and D8‐46 hydraulic nozzles respectively. Airborne glyphosate and off‐target glyphosate deposits on ground sheets and foliar surfaces were measured at downwind distances between 50 and 200 m from multiple overlaid crosswind swaths. Over this distance airborne glyphosate decreased by factors of 3‐130, ground deposits by factors of 4‐2200, and foliar deposits by factors of 5‐100. In general, airborne glyphosate and off‐target deposit was highest from the D8‐46 application, and lowest from the ‘Microfoil’ boom application. Using these measurements, mathematical equations were formulated to predict glyphosate deposits on water surfaces downwind of multiple swath applications, and calculations made for 100‐ha applications. Large‐drop drift was also calculated using a ballistic model. An estimate was then made of buffer widths required around water bodies to prevent toxicological effects from small‐ and large‐drop drift, using reported glyphosate toxicities to salmon, rainbow trout and various aquatic invertebrates. A buffer width of 25 m around water bodies limits mortality in populations of salmon, rainbow trout and aquatic invertebrates to less than 10% for the application methods employing the ‘Microfoil’ and ‘Thru Valve’ Boom. For the third application method a 30‐m buffer width is suggested.
Catalytic hydrolysis of diclofop‐methyl on Ca‐, Na‐ and K‐montmorillonites
Authors: Pusino Alba , Gessa Carlo
Published: November 2006

The decomposition of the herbicide diclofop‐methyl (methyl (RS)‐2‐(4‐(2,4‐dichlorophenoxy)phenoxy)propionate), on homoionic Ca‐, Na‐ and K‐montmorillonite in hydroalcoholic suspension was investigated. The results show that the solvolysis of the pesticide affords two products: diclofop (RS)‐2‐(4‐(2,4‐dichlorophenoxy)phenoxy)propionic acid) and diclofop‐ethyl (ethyl (RS)‐2‐(4‐(22,4‐dichlorophenoxy)phenoxy)propionate). The former is always the main product of hydrolysis on the Ca‐, Na‐ and K‐clays, whereas the latter, arising from a transesterification reaction, is favoured only by the presence of Ca‐and Na‐clays. The solvolysis reaction follows the adsorption of the herbicide on the clay, as evidenced by the shift of the IR stretching value of the ester group of the molecule, depending on the polarising power of the saturating ions.
Field movement and persistence of fenamiphos in drip‐irrigated pineapple soils
Authors: Schneider Randi C. , Green Richard E. , Apt Walter J. , Bartholomew Duane P. , Caswell Edward P.
Published: November 2006

The persistence and mobility of fenamiphos and its toxic oxidation products in soil with pineapple cropping were studied in three field experiments on the islands of Oahu and Lanai, and by sampling three commercial fields on Oahu. Fenamiphos was applied by drip irrigation after planting, following pre‐plant application of 1,3‐dichloropropene (1,3‐D) in most treatments. The Oahu experiments, conducted on highly weathered Oxisol and Ultisol soils, evaluated the impact of restricted irrigation to reduce leaching and also the effect of 1,3‐D on fenamiphos behavior. Total toxic residue (TTR) concentrations of 1000 ug kg−1 or greater were maintained in the root‐zone with fenamiphos applications of 3.4 kg ha−1 tri‐monthly on the Oxisol (Kunia site) and bi‐monthly on the Ultisol (Whitmore site). The relatively high applications, along with weekly irrigations and unseasonably high rainfall, resulted in leaching of fenamiphos TTR out of the root‐zone with concentrations between 10 and 100 ug kg−1 at 3 m depth. Reduced leaching with restricted irrigation was evident in the early months of both Oahu experiments. The potential to minimize leaching of fenamiphos by reduced application rates and limited irrigation during rainy periods was evident from nematicide concentration profiles measured on three commercial pineapple fields on Oahu; little fenamiphos TTR was detectable below 1 m.
Interaction of formamidine pesticides with insect neural octopamine receptors: Effects on radioligand binding and cyclic AMP production
Authors: Orr Gregory L. , Orr Nailah , Cornfield Linda , Gole John W. D. , Downer Roger G. H.
Published: November 2006

The formamidines chlordimeform, demethylchlordimeform (DCDM), amitraz and BTS‐2727l were tested for their respective abilities to inhibit [3H]mianserin binding in membrane preparations of cockroach brain and, in the same tissue, to stimulate octopamine‐sensitive receptors coupled to adenylate cyclase. Analysis of [3H]mianserin binding indicated negative cooperativity between two binding sites with respective Kd and Bmax values of 3.82 mM and 0.886 pmol (mg protein)−1 for a high‐affinity site and 218 nM and 13.56pmol (mg protein)−1 for a low‐affinity site. DCDM, BTS‐27271 and amitraz inhibit [3H]mianserin binding with IC50 values similar to those obtained with octopamine and the μ‐adrenergic antagonist, phentolamine, whereas chlordimeform is a poor competitor for the binding sites. Similarly DCDM, BTS‐27271 and amitraz elevate cyclic AMP production in brain membrane preparations in a dose‐dependent manner with Ka values of 0.32 uM, 1.5 uM and 3.4 uM respectively, whereas chlordimeform was again without effect. The formamidine‐mediated responses were fully additive with the evaluation of cyclic AMP obtained using the maximal concentration of dopamine but not with octopamine‐mediated increases; thus the formamidine effects appear to be expressed through partial agonism of octopamine receptors that are coupled to adenylate cyclase.
Insecticidal activity of fatty acid constituents of fixed vegetable oils against Callosobruchus maculatus (F.) on cowpea
Authors: Don‐Pedro Kio N.
Published: November 2006

The insecticidal activity of lauric, oleic and linoleic acids against Callosobruchus maculatus on cowpea was investigated in laboratory bioassays. In pre‐oviposition grain treatments, it was found that, at dosages between 1.96 and 11.59 kg‐lauric acid had no effect on progeny development, while the oily oleic and linoleic acids were active in reducing progeny development. The active fatty acids had no effect on oviposition (in no‐choice experiments) or on mortality of adults or larvae that successfully penetrated treated cowpea seeds, and their insecticidal activity, like that of fixed vegetable oils, depended mainly on ovicidal action. When applied to cowpeas in a pure state, oleic acid had an LC50 value of 1.64mlkg−1, which made it approximately 3 and 8 times more toxic against eggs of C. maculatus than groundnut oil and linoleic acid respectively. When the ovicidal activities of the three fatty acids were tested by dipping egg‐infested seeds in acetone‐ based solutions, they were all found to be similarly toxic, lauric, oleic and linoleic acids having LC50, values of 40, 38 and 26 ml litre−1 respectively (with overlapping 95% C.L.). These values made them 2‐4 times more toxic than acetone‐based solutions of groundnut and traditional coconut oils. The possibility of employing fatty acids in large‐scale and traditional small‐scale food storage systems is discussed.
Methacrifos as a grain protectant: A comparison of the vapour effects of some organophosphorus insecticides used in grain protection
Authors: Price Nicholas R. , Hoppe Thomas , Watson Helen
Published: November 2006

A simple Sradiochemical method was devised for the estimation at ambient temperatures of vapour uptake and toxicity of relatively non‐volatile organophosphorus insecticides to the red flour beetle Tribolium castaneum. Over a three‐day period the insecticides pirimiphos‐methyl and chlorpyrifos‐methyl exhibited no vapour activity and only small amounts of vapour were accumulated by test insects. Methacrifos appeared to be much more active as a vapour and much of its toxic action in an ideal situation could be attributed to this phenomenon.
Enhancement of neurotransmitter release from invertebrate synaptosomes by pyrethroids during pulsed‐depolarization: A functional assay for effects on repolarization
Authors: Clark J. Marshall , Matsumura Fumio
Published: November 2006

The release of [3H]neurotransmitters was used as a functional assay to assess the actions of selected neurotoxins on the synaptosomal membranes prepared from the invertebrate nervous systems of squid and house fly. A reproducible release of [3]neurotransmitter was evoked by pulsed‐depolarization in the presence of elevated K+ or of veratridine. Pretreatment with deltamethrin resulted in a substantial enhancement of [3H]neuro‐transmitter release during pulsed‐depolarization. This enhanced neurotransmitter release was greatly reduced or absent when synaptosomes of knockdown‐resistant house flies were examined. No enhanced neurotransmitter release due to deltamethrin pretreatment was apparent from any synaptosomal preparation under non‐depolarizing conditions. Under similar conditions, collaborative experiments demonstrated that deltamethrin causes a significant change in protein phosphorylation activities which follow depolarization. The most significant change caused by deltamethrin was the prolonged elevation of the level of phosphorylation on a number of key synaptic proteins beyond the normal time of their recovery to the dephosphorylated state. The most notable protein reacting to deltamethrin in this manner was calcium‐cadlmodulin‐dependent protein kinase.
Metribuzin degradation in soil: I—effects of soybean residue amendment, metribuzin level, and soil depth
Authors: Locke Martin A. , Harper Sidney S.
Published: November 2006

Plant residue and soil depth effects on metribuzin degradation were investigated. Dundee silt loam soil collected at depth increments of 0–10 cm (SUR) and 10–35 cm (SUB) was treated with labeled [5−14 C]metribuzin. Samples were assayed at several time points up to 140 days after treatment. Soybean residue was added to half of the SUR samples (RES), with remaining SUR unamended (NORES). None of the SUB samples were amended with soybean residue. Metribuzin mineralization to 14CO2 proceeded more slowly in RES and SUB than in NORES and SUR, respectively. Extractable components in SUR samples included polar metabolites, plus deaminated metribuzin (DA) in the RES, and parent metribuzin in the NORES. Deaminated diketometribuzin (DADK) and metribuzin comprised major 14C components extracted from SUB, while in SUR, faster degradation of metabolites resulted in metrizubin as the primary identifiable compound. Unextractable 14C increased until day 35 for both RES and NORES, after which it remained constant for NORES. but declined for RES. A corresponding rise in RES polar 14C suggested that as soybean residue decomposed, 14C bound in the residue was released as extractable polar material. Soil with soybean residue accumulation may alter metabolite degradation patterns, but does not impede initial metribuzin degradation. Depth differences in metribuzin degradation were attributed to reductions in microbial activity with increasing soil depth.
Metribuzin degradation in soil: II—effects of tillage
Authors: Locke Martin A. , Harper Sidney S.
Published: November 2006

A 140‐day laboratory incubation, using surface soil from a long‐term soybean tillage study, evaluated tillage influence on [14C]metribuzin degradation. Higher plant residue conditions in no‐tillage (NT) soil inhibited metribuzin mineralization to [14C]carbon dioxide as compared to metribuzin degradation patterns observed in conventional tillage (CT) soil. At 140 days, relative abundance of extractable 14C components in NT included polar metabolites > metribuzin = deaminated metribuzin (DA) = deaminated diketometribuzin (DADK), while in CT, components included metribuzin > polar metabolites > DADK≫DA. Conditions in NT apparently inhibited polar 14C degradation, and resulted in its accumulation, while in CT polar 14C degradation proceeded relatively rapidly. For both NT and CT, more 14 C was measured in an unextractable fraction than in any other fraction. A greater portion of the unextractable fraction in NT was associated with decomposed plant residue than in CT. Surface accumulation of crop residue, such as occurs under NT, provided a soil environment which altered metribuzin degradation patterns.
Inhibition of acetolactate synthase in susceptible and resistant biotypes of Stellaria media
Authors: Devine Malcolm D. , Maries M. A. Susan , Hall Linda M.
Published: November 2006

Acetolactate synthase (ALS) from one susceptible and two chlorsulfuronresistant biotypes of Stellaria media(L.) Vill. was assayed in the presence of eight known ALS inhibitors. As expected, ALS from the chlorsulfuronresistant biotypes (R1 and R2) showed reduced sensitivity to chlorsulfuron and other sulfonylurea herbicides. The patterns of cross‐resistance varied, however, indicating that the alteration in ALS that confers chlorsulfuron resistance does not confer the same level of resistance to other sulfonylurea herbicides. The resistant biotypes were highly cross‐resistant to sulfometuron‐methyl and DPX‐A7H81, but less cross‐resistant to triasulfuron. Both R1 and R2 were highly cross‐resistant to DTPS (N‐[2,6‐dichlorophenyl]‐5,7‐dimethyl‐1,2,4‐iriazolo[1,5a]pyrimidine‐2‐siilfoiiamide), but only slightly cross‐resistant to imazamethahenz, an imidazolinone herbicide. The differences in the patterns of cross‐resistance observed presumably reflect differences in the binding affinity of the herbicides for the altered ALS. The data presented suggest, but do not confirm, that R1 and R2 contain the same ALS mutation.
Development and validation of a modified fugacity model of pesticide leaching from farmland
Authors: Brooke David , Matthiessen Peter
Published: November 2006

To test whether a simple model could provide reasonable quantitative estimates of chemical concentrations in a dynamic situation, Mackay's fugacity model was adapted to represent an agricultural field. The intention was to determine the extent of modification required to obtain reasonable agreement with experimental results, or indeed if such agreement could be achieved. The validity of the model was tested at Rosemaund Experimental Husbandry Farm in Herefordshire, where the chemical input and output could be monitored and meteorological and other parameters measured regularly. Results from monitoring concentrations of two pesticides at this site in recent years, and changes that have been made to the model in attempting to fit the observed behaviour are described.
Application and validation of pesticide leaching models
Authors: Klein Michael
Published: November 2006

Two lysimeter studies with the pesticides cloethocarb and bentazone were used to validate a modified version of the computer model SESOIL (Seasonal Soil Compartment Model), developed by Bonazountas and Wagner and to transfer the results of the lysimeter study to another climate scenario. For cloethocarb, an experimental insecticide without marked mobility in the soil, as indicated by the lysimeter study, the simulations were in excellent agreement with the lysimeter study. Calculations for bentazone revealed higher leaching than found in the lysimeter study. This discrepancy was resolved by a more careful and realistic inclusion of sorption in the lysimeter soil into the simulation model.
Synthetic and mechanistic studies on fungal metabolic pathways: A guide to fungicide design
Authors: Simpson Thomas J. , Dillon Michael P. , Donovan Tessa M.
Published: November 2006

The polyketide biosynthetic pathway is responsible for the formation in microorganisms and plants of a vast array of diverse structures, many of which display important biological activity. A brief overview of the pathway, with emphasis on present problems and future developments, is presented and the impact of genetics on chemical and biochemical studies of polyketide biosynthesis is highlighted.

Biosynthetic and mechanistic studies on three pathways are described, to illustrate how these studies may provide an insight into the mode of action of particular compounds, or how particular pathways may be inhibited. LL‐D253α is an antibiotic chromanone produced by a number of Phoma species. Stable isotope labelling studies have indicated the involvement of cyclopropylcyclohexadienyl intermediates in the formation of the hydroxyethyl side chain indicating a possible mode of action. Similar studies of monocerin indicate the involvement of quinone methide intermediates. A synthesis of monocerin, modelled on the biosynthetic pathway, is described. Scytalone and vermelone are intermediates on the pathway to melanin in certain pathogenic fungi, e.g. Pyricularia oryzae. Progress with biosynthetic studies on this pathway is described.
Dialkyl phosphorofluoridates and alkyl methylphosphonofluoridates as disruptants of moth sex pheromone‐mediated behavior
Authors: Malik Mangel S. , Vetter Richard S. , Baker Thomas C. , Roy Fukuto T.
Published: November 2006

A series of dialkyl phosphorofluoridates and alkyl methylphosphono‐fluoridates in which one or two of the alkyl moieties were long‐chain alkyl groups were synthesized and examined for their ability to disrupt moth sex pheromone‐mediated behavior of the oriental fruit moth, Grapholita molesta. Disruption of pheromone‐mediated behavior was found only for those compounds containing a (Z)‐8‐dodecenyl moiety, i.e. the alkyl substituent of the principal pheromone component ((Z)‐8‐dodecenyl acetate) of the oriental fruit moth. Di‐((Z)‐8‐dodecenyl) phosphorofluoridate was nearly as disruptive as (Z)‐8‐dodecenyl acetate.
Efficacies of low‐ to high‐volume (960‐10 700 litre ha− 1) citrus sprayers for applying petroleum spray oil to control chinese wax scale
Authors: Beattie G. Andrew C. , Clift Alan D. , Allender William J. , Jiang Laura , Wang Ye A.
Published: November 2006

Petroleum spray oil (2, 4 and 6% in water) was applied to Valencia orange, Citrus sinensis (L.) Osbeck, for the control of Chinese wax scale, Ceroplastes sinensis del Guercio, using a low‐volume ( <2000 litre ha−1)air‐blast (LV AB) sprayer, a low‐ to high‐volume (L‐HV) (up to 7000 litre ha−1) sprayer with four fan‐assisted rotary atomiser (FARA) spray heads mounted on a vertical tower, and a high‐volume (>7000 litre ha−1) oscillating boom (HV OB) sprayer. The most effective sprayer was the L‐HV FARA sprayer. The most cost‐effective treatment was a 20 ml litre−1 (60 litre oil ha−1) spray applied at 3000 litre ha−1 by the L‐HV FARA sprayer. It gave mortality equivalent to a standard 20 ml litre−1, 10 700 litre ha−1 spray (214 litre oil ha−1) applied by the HV OB sprayer but with 72% less spray and significantly less oil deposited per cm2 of leaf area. Equivalent or significantly (P = 0·05) higher mortality than that given by the 10 700 litre ha−1 HV OB spray was given by the 40 ml litre−1, 3000 (120 litre oil ha−1) and 60 ml litre−1, 2180 and 3000 litre ha−1 (130·8 and 180 litre oil ha−1) L‐HV FARA sprays, but the 60 ml litre−1 sprays deposited more oil per cm2 than the 20 ml litre−1 HV OB spray and were considered to be potentially phytotoxic. The least effective sprayer was the LV AB sprayer, which applied a 60 ml litre−1 spray (57·6 litre oil ha−1) at 960 litre ha−1. Linear relationships were established for Chinese wax scale mortality, transformed using an angular transformation (arcsin proportion), versus log10 spray volume for the 20, 40 and 60 ml litre−1 sprays applied by L‐HV FARA at 1260,2180 and 3000 litre ha−1, mortality versus log10 μg oil cm−2 and log10 μg oil versus log10 volume of oil sprayed.
Synthesis and herbicidal activity of 2‐(1,3‐dimethyl‐4‐substituted‐5‐pyrazolyl)sulfonylimino‐5,7‐disubstituted‐2H‐1,2,4‐thiadiazolo[2,3‐a]pyrimidine derivatives
Authors: Okajima Nobuyuki , Aoki Isao , Kuragano Takashi , Okada Yoshiyuki
Published: November 2006

A series of 2‐(1,3‐dimethyl‐4‐substituted‐5‐pyrazolyl)sulfonylimino‐5,7‐disubstituted‐2H‐1,2,4‐thiadiazolo[2,3‐a]pyrimidines was synthesized and tested for herbicidal effects. The compounds showed potent activity and improved selectivity to rice when compared with analogous sulfonylurea derivatives.