bluuebunny/crossref_metadata_2025 huggingface dataset:
The kinetics of insecticide action. Part III: The use of stochastic modelling to investigate the pick‐up of insecticides from ULV‐treated surfaces by larvae of Spodoptera littoralis boisd
Authors: Salt David W. , Ford Martyn G.
Published: November 2006

The pick‐up of pesticide by lepidopterous larvae walking across ultra‐low volume pesticide treated surfaces has been stochastically modelled and simulated using a computer. The duration of the random walk was considered as a series of small, discrete time intervals during which the mode of pick‐up varied, depending upon the behavioural state (resting, feeding or walking) of a larva. Estimates can be obtained for the total mass picked up by the larva (gross) and the net amount eliminated, the internal exposure to insecticide, and the proportion of insects knocked down and killed with increasing time. The results of the simulation of Spodoptera littoralis larvae confined to permethrin‐treated surfaces were in agreement with experimental data, and suggested that a high pick‐up of insecticidal droplets resulted from adhesion of the pesticide to larvae following encounter. However, the availability of drops at the leaf surface decreased with time, probably as a result of droplet spread and subsequent uptake by the cuticular waxes. Droplet stability on leaf surfaces may be related to droplet size.
A rapid quantitative bioassay for the determination of biologically available bromacil in soils
Authors: Bennett Paul H. , De Beer Pieter R.
Published: November 2006

A simple rapid bioassay is described for the determination of biologically available bromacil residues in soils. A clear aqueous extract was made from a soil fortified with a known amount of the herbicide, and similar extracts were made from samples of soil taken from plots that had been sprayed with a bromacil formulation at a rate of 4 kg ha−1. Samples of these extracts were added to a suspension of the unicellular green alga Selenastrum capricornutum. The net photosynthetic oxygen production by the alga was then measured using an oxygen electrode. The results were expressed as a percentage of the oxygen production by a control suspension. The concentration of biologically available bromacil was determined by reference to a previously established dose‐response curve of the percentage reduction in oxygen production against bromacil concentration. The accuracy of this bioassay was determined by comparing the results with those obtained using capillary gas‐liquid chromatography. The results obtained by the two different methods showed good agreement.
Synthesis and insect growth regulating activity of thiosemicarbazones of methyl 2‐pyridyl ketones
Authors: Pedersen Lars‐Erik K. , Svendsen Axel , Klemmensen Per D.
Published: November 2006

Thirty‐six thiosemicarbazones of methyl 2‐pyridyl ketone and of some other methyl ketones were tested on Dysdercus cingulatus, Drosophila melanogaster, Locusta migratoria, Aedes aegypti, Tenebrio molitor and Musca domestica. Several derivatives were toxic, delaying or preventing ecdysis. The structure‐activity relationship is discussed. The mode of action of these compounds appears to be different from that of juvenile hormones, anti‐juvenile hormones, or chitin biosynthesis inhibitors.
New conjugated metabolites of 3‐phenoxybenzoic acid in plants
Authors: Mikami Nobuyoshi , Wakabayashi Noriko , Yamada Hirohiko , Miyamoto Junshi
Published: November 2006

The metabolism of 3‐phenoxybenzoic acid, a common plant metabolite of deltamethrin, cypermethrin and fenvalerate, has been studied in abscised leaves of cabbage, cotton, cucumber, kidney bean and tomato plants. The [14C]‐acid was readily converted into more polar conjugates by esterification with glucose, 6‐O‐malonylglucose, gentiobiose, cellobiose, glucosylxylose and two types of triglucose with different isomerism. Other metabolites identified were the glucosyl ether of 3‐(4‐hydroxyphenoxy)benzoic acid, and a 3‐(2‐hydroxyphenoxy)benzoic acid derivative with a total of two molar equivalents of glucose linked to the carboxyl and phenolic ‐OH groups. The conjugation pathways were somewhat plant‐specific. The glucosylxylose ester was found only in cotton, and the cellobiose and triglucose esters were found only in tomato. All of the conjugates except the glucose and glucosylxylose esters were plant metabolites that had not been identified previously. Furthermore, this is the first report to show the presence of cellobiose and triglucose conjugates in plants. However, neither of the acetyl derivatives of the [14C]‐triglucoside was identical with the synthetic deca‐acetyl derivative of [1→6]‐triglucoside.
Field experiments on the effects of a new pyrethroid insecticide WL‐85871 on bees foraging artificial aphid honeydew on winter wheat
Authors: Shires Stephen W. , Blanc Jean Le , Debray Philippe , Forbes Stuart , Louveaux Jean
Published: November 2006

Two large and two small plots of winter wheat were enclosed beneath large mesh‐covered tunnels. A small beehive was placed in each tunnel and sucrose solution was sprayed on to all of the wheat in order to simulate aphid honeydew. WL‐85871 (a 1:1 mixture of two stereoisomers of cypermethrin) as ‘Fastac’ at three dose rates, dimethoate, pirimicarb or water were applied to the larger plots of wheat when the bees were actively foraging the sugar deposits. No increase in bee mortality, compared with that in the pre‐treatment period, was observed after the applications of WL‐85871 or pirimicarb. By contrast, large numbers of dead bees were found following the applications of dimethoate. Foraging activity in the plots, treated with all dose rates of WL‐85871 or with pirimicarb, declined sharply after treatment and remained at a reduced level. With dimethoate no foraging activity occurred after application in either the treated or untreated plots. Only very low concentrations of WL‐85871 were detected in post‐treament samples of honey, wax, and live or dead bees. It was concluded that the application of WL‐85871, to wheat already treated with artificial honeydew, resulted in no adverse effects on the honey‐bee colonies.
Multiresidue method for captan, folpet, captafol, vinclozolin and iprodione on italian apples and pears by capillary gas–liquid chromatography with electron‐capture detection
Authors: Taccheo M. Barbina , Spessotto Claudio , Bresin Bruno , Bagarolo Lucia
Published: November 2006

A method is described for the simultaneous determination of residues of five fungicides used for foliar treatment of apple and pear trees, and for postharvest application. After extraction, the mixture of these fungicides is cleaned‐up on a ‘SEP PAK C18’ cartridge and the components determined by gas‐liquid chromatography with electron‐capture detection. The minimum detectable amounts in apples and pears, on a fresh weight basis, were 0.005mg kg−1 for vinclozolin, 0.010mg kg−1 for captan, folpet and iprodione, and 0.020 mg kg−1 for captafol. The percentage recovery for each fungicide (calculated by analysing four samples of untreated apples and pears, to which varying concentrations of each active ingredient had been added) varied for vinclozolin between 70.0 and 89.2, for captan between 72.0 and 83.8, for folpet between 73.0 and 93.0, for captafol between 70.8 and 91.8, and for iprodione between 75.1 and 97.1.
Metabolism in rats of 3‐phenoxybenzyl alcohol and 3‐phenoxybenzoic acid glucoside conjugates formed in plants
Authors: Mikami Nobuyoshi , Yoshimura Jun , Kaneko Hideo , Yamada Hirohiko , Miyamoto Junshi
Published: November 2006

Upon single oral administration to rats, the mono‐, di‐ and tri‐glucose conjugates of [14C]‐3‐phenoxybenzyl alcohol (I) or the mono‐glucose conjugate of [14C]‐3‐phenoxybenzoic acid (II) were rapidly hydrolysed and extensively eliminated in the urine mostly as the sulphate conjugate of 3‐(4‐hydroxyphenoxy)benzoic acid (X). The faecal elimination was a minor route, whereas the biliary excretion was about 42% of the dose and the glucuronide conjugates of I, II and X were common major metabolites. The biliary glucuronides were cleaved in the small intestine to the respective aglycones, which were reabsorbed, metabolised further, and excreted in the urine as the sulphate conjugate of X. Although small amounts of the mono‐, di‐and tri‐glucosides were found in the 0.5‐h blood and liver samples following oral administration of the tri‐glucoside of I, they were not detected in the urine, bile or faeces. Similarly the sulphate conjugate was one of the major urinary metabolites of germ‐free rats, dosed with the 14C‐glucosides via the oral or the intraperitoneal route, although they were excreted unchanged in certain amounts in the urine and faeces. The glucose conjugates were cleaved in vitro by gut microflora and in various rat tissues, including blood, liver, small intestine and small intestinal mucosa. The tissue enzymes showed a different substrate specificity in hydrolysis of the glucosides. However, they were not cleaved in gastric juice, bile, pancreatic juice or urine.
The metabolism of fenvalerate in plants: The conjugation of the acid moiety
Authors: Mikami Nobuyoshi , Wakabayashi Noriko , Yamada Hirohiko , Miyamoto Junshi
Published: November 2006

The metabolism of the pyrethroid insecticide fenvalerate [(RS)‐α‐cyano‐3‐phenoxybenzyl (RS)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate] (I), and of its most insecticidal (αS,2S) isomer (II), has been examined in cabbage plants grown and treated under laboratory conditions with [14C]chlorophenyl‐ and [ring‐14C]benzyllabelled preparations of the two compounds. Both insecticides disappeared from the treated leaves with similar half‐lives of approximately 12–14 days; they underwent ester cleavage to a significant extent, together with some hydroxylation at the 2‐ or 4‐position of the phenoxy ring, and hydrolysis of the nitrile group to amide and carboxyl groups. Most of the carboxylic acids and phenols thus produced occurred as glycoside conjugates. In separate experiments, the uptake and metabolism of 2‐(4‐chlorophenyl)‐3‐methylbutyric acid (X), the acidic half of the molecule, were examined in the laboratory, using abscised leaves of kidney bean, cabbage, cotton, cucumber and tomato plants. The acid X was found to be readily converted, mainly into glucose and 6‐O‐malonylglucose esters in kidney bean, cabbage and cucumber plants, into glucosylxylose, sophorose and gentiobiose esters in cotton, and into two types of triglucose esters with differing isomerism in tomato. One of the acetyl derivatives of the trisaccharide conjugates was identical with the synthetic deca‐acetyl derivative of the [1 → 6]‐triglucose ester.
Inhibitors of juvenile hormone biosynthesis incorpora allataof the cockroachPeriplaneta americana(L.)in vitro
Authors: Brooks Gerald T. , Pratt Grahame E. , Mace David W. , Cocks John A.
Published: November 2006

The spontaneous biosynthesis of methyl (2E,6E)‐(10R)‐10,11‐epoxy‐3,7,11‐trimethyldodeca‐2,6‐dienoate (juvenile hormone III; JH III) in excisedcorpora allataofPeriplaneta americanawas inhibited by a number of synthetic prop‐2‐ynyl ethers and 1,3‐benzodioxole derivatives. One structurally diverse group of compounds inhibited only the final biosynthetic enzyme methyl farnesoate epoxidase (EC.1.14.14.–) at low to moderate concentrations, but at higher concentrations, also inhibited methyl farnesoate (MF) formation, causing an accumulation of MF in the concentration range 10 to 100 μM. For a second, more limited, group of compounds, there was close congruence between the inhibition of JH III biosynthesis and that of total ester (MF plus JH III) biosynthesis over their effective inhibitory concentration ranges. In contrast to the first group, there was no accumulation of MF and these compounds evidently inhibited JH III biosynthesis, at the level of either farnesoic acid esterification by O‐methyl transferase (EC.2.1.1.–), or at an earlier step in the biosynthetic pathway that remains to be elucidated.
Dimethoate spray residues in strawberries
Authors: Goodwin Stephen , Ahmad Nazir , Newell Graeme
Published: November 2006

Strawberries were sprayed with solutions of 200, 300 and 500 mg dimethoate litre−1 and analysed for dimethoate residues up to 21 days after the final spraying. The residues were found to be below the National Health and Medical Research Council limit of 2 mg kg−1, 1, 2 and 4 days after spraying. Consequently, the withholding period of 7 days could be reduced to 3 days to allow uninterrupted picking of the ripe strawberry crop.
Inhibition of aflatoxin production in Aspergillus flavus by pyrazolines and pyrazoles
Authors: Latif Nazih , Mishriky Nawal , Haggag Bahiga , Elshayeb Nefesa , Mabrouk Sohair
Published: November 2006

A new series of 1,3,5‐triarylpyrazolines, obtained from 3, 4‐dichloroacetophenone, were readily dehydrogenated by tetrachloro‐o‐benzoquinone at room temperature to the pyrazoles. The spectra and fluorescence of the compounds are discussed. The pyrazolines and pyrazoles did not significantly affect the mycelial growth of 19 fungal isolates, but at low concentrations, they inhibited aflatoxin production by Aspergillus flavus.
Analysis of soils for diclofop‐methyl and diclofop
Authors: Johnstone Patricia K. , Minchinton Ian R. , Truscott Roger J. W.
Published: November 2006

A method is described for the analysis of soils for residues of the herbicide diclofop‐methyl, methyl (RS)‐2‐[4‐(2,4‐dichlorophenoxy)phenoxy]propionate, and its breakdown product diclofop, (RS)‐2‐[4‐(2,4‐dichlorophenoxy)phenoxy]propionic acid. Diclofop‐methyl undergoes hydrolysis in the soil to diclofop, which also has herbicidal activity. A procedure, using a 1% phosphoric acid solution for extraction purposes, has been developed and gives good recoveries of both diclofop‐methyl and diclofop at the 0.5 and 0.05 mg kg−1 levels. After methylation, gas‐liquid chromatography with electron‐capture detection is used to determine total residue concentrations.
Toxic and repellent effects of cypermethrin on the honeybee: Laboratory, glasshouse and field experiments
Authors: Delabie Jacques , Bos Christian , Fonta Caroline , Masson Claudine
Published: November 2006

Cypermethrin is highly toxic to the honeybee Apis mellifera ligustica. The action of the chemical is rapid (within 2 days) and it has no long‐term effects. The sensitivity of the bees increases with decrease in breeding temperature and with increasing age of the insect. The commercial formulation ‘QCymbush’ is repellent to bees: the effect appears to be due to the formulation ingredients because cypermethrin itself is not repellent. A floral odour lost its natural attractiveness in the presence of ‘Cymbush’. The repellency appears to persist for some 2 days after treatment, during which time the bees learnt to avoid the crop. No residues of cypermethrin were found in the hive products (pollen, wax or honey), nor in the oilseed rape at harvest.
An olfactometer for measuring the repellent effect of chemicals on the stable fly Stomoxys calcitrans (L.)
Authors: Bartlett Christopher
Published: November 2006

An olfactometer is described that permits the evaluation of chemicals acting in the vapour phase against the stable fly Stomoxys calcitrans (L.). Hungry flies, held in a metal frame cage covered with soft gauze, are attracted to a target held adjacent to one side of the cage, and emitting an attractive airflow. Flies landing on the target are counted at intervals of 15s. Flies starved for 24h were tested in the olfactometer when 2, 3 and 4 days old. With the exception of the first exposure of the 4‐day‐old flies, all the flies of the three ages showed greater than 80% attraction to the olfactometer target after exposure for 2 min, for each of four successive exposures at 10‐min intervals. For all ages there was a significant increase in attraction at the second exposure but no further increase with subsequent exposures. It is likely that the sensillae, stimulated by the first exposure, subsequently responded faster. Eight chemicals were incorporated into the airflow behind the target to test their effect on flies. Permethrin (a low vapour pressure pyrethroid) and crotoxyphos (a low vapour pressure organophosphate) did not act in the vapour phase. Empenthrin (a high vapour pressure pyrethroid) and dichlorvos (a high vapour pressure organophosphate) both exhibited the toxic effect of knock‐down on the flies without repellency. Oil of citronella and citronellol, two known fly repellents, gave a general reduction of attraction that was dose dependent; fewer flies found the target and those that did stayed a shorter length of time. Natural pyrethrum gave a similar effect to these two at lower concentrations, but at higher concentrations, it also showed a repellent effect. N,N‐Diethyl‐m‐toluamide gave a low reduction in attraction. The olfactometer shows potential for use with other flying insects, both to observe the effects of an insecticide and also to study the behavioural responses in the absence of insecticides.
The effect of 2,2‐dimethylchromene derivatives and some other compounds on the development ofOncopeltus fasciatus(dallas) andLocusta migratoria migratorioides(R&F)
Authors: Brooks Gerald T. , Ottridge Anthony P. , Jennings Richard C. , Mace David W. , Alexander B. Alan
Published: November 2006

As an adjunct to biochemical studies on the action of juvenile hormone antagonists (‘antijuvenile hormones’), a study has been made of the effects on insect development of 71 compounds based on the 2,2‐dimethylchromene structure, and 30 other compounds, including especially chemicals containing acetylenic and 1,3‐benzodioxole (methylenedioxyphenyl) groups, that were expected to inhibit microsomal mixed function oxidases. The ageratochromenes, 7‐methoxy‐2,2‐dimethylchromene and 6,7‐dimethoxy‐2,2‐dimethylchromene (precocene I and precocene II, respectively), were used for comparison. With the jar deposit method used forOncopeltus fasciatus, and the topical application method used forLocusta migratoria, only derivatives of 2,2‐dimethylchromene and 2‐(3‐methylbut‐2‐enyl)phenol, the alkene double bonds of which were activated by an alkoxy group, exhibited characteristic antijuvenile hormone actions. In the whole life‐cycle exposure test onO. fasciatus, a number of other compounds had non‐specific effects on development, especially at the fifth instar. Some of the compounds, including certain derivatives of 2,2‐dimethylchromene with ester side‐chains, had juvenile hormone agonist actions. The scope for structural optimization for antijuvenile hormone action in the 2,2‐dimethylchromene series appears to be limited, and structure‐activity relationships are obscured, especially forO. fasciatus, by an overlap between the prothetelic morphogenetic and lethal effects. The results are discussed in relation to the mode of action of the 2,2‐dimethychromenes.
A simple bioassay for detecting and characterising insecticide resistance
Authors: Bloomquist Jeffrey R. , Miller Thomas A.
Published: November 2006

A simple and rapid paralysis assay was developed to detect and characterise knockdown resistance in larvae of the house fly and pink bollworm. Pyrethroidtreated larvae unable to perform a stereotypic curling movement when probed with a warm needle, 10 min (house fly) or 60 min (pink bollworm) after treatment, were considered to be paralysed. Responses in a susceptible strain of house fly were compared with those of the pyrethroid‐resistant strains kdr and super‐kdr. In this assay, the kdr strain displayed over 28 fold resistance to deltamethrin, and super‐kdr larvae were unaffected by doses up to 100μg. These results are in good qualitative agreement with previous studies. The assay detected no significant fenvalerate resistance in pink bollworm larvae collected from the field; this was consistent with mortality bioassays performed on wild adult males. The limitations and potential utility of the paralysis bioassay in resistance screening are discussed.
Mode of action of the anthelmintics morantel, pyrantel and levamisole on muscle cell membrane of the nematode Ascaris suum
Authors: Harrow Ian D. , Gration Kenneth A. F.
Published: November 2006

Intracellular current and voltage clamp techniques were used to investigate the mode of action of the anthelmintics, morantel, pyrantel and levamisole applied to the bag region of Ascaris suum muscle cells. Microperfusion of the anthelmintics and of O‐acetylcholine (ACh) increased the input conductance and depolarised the membrane potential of the muscle bags. The relative potencies of these drugs were determined from dose–conductance relationships and found to be: morantel = pyrantel > levamisole > ACh. High doses (>10μM) of morantel caused antagonism of ACh responses. ACh‐induced currents were measured under voltage clamp (over the range −80 to +10mV). At membrane potentials between −80 and 0 mV, microperfusion of ACh induced a voltage‐dependent inward current. The current–voltage relationship was linear for membrane potentials in the range −30 to +10mV. The reversal potential was measured directly and found to be about +10mV. The relationship became non‐linear at membrane potentials more negative than −30 mV, and the degree of non‐linearity was dependent upon the concentration of ACh. The current–voltage relationships for morantel, pyrantel and levamisole also possessed both linear (−30 to 0mV) and non‐linear components. The reversal potential for each agonist, determined by extrapolation of the linear component of the current–voltage relationship, was approximately +10mV, indicating the same cation channels were activated both by ACh and the anthelmintics. Evidence for competition between ACh and pyrantel for the same membrane receptor was obtained using iontophoretic delivery of each agonist from a double‐barrelled micropipette. It is concluded that the anthelmintics, morantel, pyrantel and levamisole act as potent agonists at ACh receptors on muscle bag membranes of A. suum.
Physiological interactions between the herbicide EPTC and selected analogues of the antidote naphthalic anhydride on two hybrids of maize
Authors: Hatzios Kriton K. , Zama Paul
Published: November 2006

The efficacies of nine structural analogues of the herbicide antidote naphthalene‐1,8‐dicarboxylic acid anhydride (naphthalic anhydride, NA) for the protection of maize (Zea mays L. cv. DeKalb XL72AA and DeKalb XL67) against injury by the herbicide S‐ethyl dipropyl(thiocarbamate) (EPTC) were elevated under greenhouse conditions. The chemical analogues of NA tested were: acenaphthenequinone (ACQ); 4‐aminonaphthalene‐1,8‐dicarboxylic acid anhydride (NH2NA); 1,8:4,5‐naphthalenetetracarboxylic acid dianhydride (NDiA); naphthalene‐ 1,8‐carboximide (NHNA); 4‐chloronaphthalene‐1,8‐dicarboxylic acid anhydride (C1NA); biphenyl‐2,2′‐dicarboxylic acid anhydride (diphenic anhydride; DA); 2‐phenylglutaric anhydride (PGA); phthalic anhydride (PHA); phenalen‐1‐one (PA). Pre‐plant incorporated applications of EPTC at 2.2, 4.5, 6.7, and 9.0 kg ha−1 were highly toxic to XL67 maize. Appreciable injury to XL72AA maize by EPTC was observed only with the high rates of EPTC (6.7 and 9.0 kg ha−1). Of the analogues tested PGA and PA were very toxic and inhibited germination of both maize hybrids. NA, ACQ, NH2NA, NDiA, NHNA, C1NA, DA, and PHA applied as seed dressings at 5.0 and 10 g per kg of seed offered satisfactory protection to XL72AA maize against EPTC rates higher than 6.7 kg ha−1. The same antidotes significantly antagonised the EPTC activity against XL67 maize but the overall protection obtained was partial and not agronomically important. The presence of the dicarboxylic anhydride group and of at least one aromatic ring attached directly to the anhydride appeared to be essential for the exhibition of protective activity by the structural analogues of NA. NA was slightly toxic to both hybrids of maize and chlorination of NA increased the phytotoxicity of this molecule. A genetic component that is present in the thiocarbamate‐tolerant XL72AA hybrid but absent from the thiocarbamate‐susceptible XL67 hybrid of maize appeared to be important for the phytotoxic activity of EPTC and may be involved in the protective activity of NA and its structural analogues.
Excretion of DDT residues into milk of the Indian buffalo, Bubalus bubalis (L.) after oral and dermal exposure
Authors: Kalra Rajinder L. , Chawla Ram P. , Joia Balbir S. , Tiwana Mewa S.
Published: November 2006

Three groups of buffaloes were fed with 20, 100 and 400 mg of p,p′‐DDT in their daily rations. The DDT residues in the milk fat of the treated animals showed an initial rapid rise but soon attained a dose‐dependent equilibrium. The transfer coefficient of DDT residues in milk at ‘plateau’ levels showed an average value of about 12%. Half‐life values for the rate of decline of DDT residues during the post‐dosing period were computed according to a two‐open‐compartment model. Dermal application of p,p′‐DDT to buffaloes also resulted in excretion of a significant amount of its residues in milk. TDE was the predominant compound present in milk when buffaloes had ingested p,p′‐DDT, whilst p,p′‐DDT itself was present in greater quantity than its metabolites when animals were treated dermally.
Theoretical considerations for the application of aromatic and heterocyclic fluorine compounds as pesticides
Authors: Pavlath Attila E.
Published: November 2006

A fluorine atom attached to an aromatic or heterocyclic system is quite stable in many chemical and biochemical reactions. Its size, in contrast to other halogen atoms, is comparable to that of a hydrogen atom and therefore, fluorine substitution does not distort the steric configuration of most compounds involved in biological processes. This can result in the incorporation of fluorinated compounds at some stage into the life cycle of various organisms. The high electronegativity of the fluorine, however, may alter considerably the reaction kinetics and mechanism of such intermediates at a later stage of the cycle causing biological disruption and possible pesticidal effect.
Fluorine‐containing intermediates for pesticides
Authors: Braden Rudolf P. J. , Klauke Erich
Published: November 2006

Compounds containing fluoro‐ or fluoroalkyl‐substituents often show interesting biological activities. However, the high cost of introducing fluorine into a molecule may make the manufacture of a compound with excellent biological activity too expensive for commercial viability. The cheapest source of fluorine is hydrogen fluoride but most fluorine substitution reactions described in the literature make use of alkali metal fluorides which, although more convenient to handle in the laboratory, are much more expensive. This paper describes the use of hydrogen fluoride in new synthetic routes to a number of intermediates for the manufacture of commercially useful pesticides. These include compounds containing the dichlorofluoromethylsulphenyl radical, derivatives of perfluoro‐2,5‐diazahexa‐2,4‐diene, various aromatic fluoro compounds and some fluorinated benzodioxoles and benzodioxenes.
Vapour pressure of permethrin
Authors: Wells David , Grayson B. Terence , Langner Eric
Published: November 2006

The vapour pressures of the separate isomers of permethrin have been determined over a range of temperatures by two laboratories using different versions of the gas saturation method. A statistical analysis of the sets of data from the two laboratories shows no significant differences for the cis isomers but a small difference in the 20°C extrapolated values for the trans isomer exists. However, this difference is discounted as arising from experimental error and the mean values of the estimated vapour pressures at 20°C are given as 2.5 μPa (cis) and 1.5 μPa (trans).
The influence of molasses on the physical properties and sprayability of two pesticide formulations
Authors: Abbott Henry A.
Published: November 2006

The effects of molasses on some of the physicochemical properties and on the sprayability of a carbaryl wettable powder (w.p.) and triazophos emulsifiable concentrate (e.c.) were studied in the laboratory and the field. When sprayed in the laboratory on bean leaves, the deposit obtained from either formulation decreased as the percentage of molasses was increased. In an aerial application field trial on cotton, 10% molasses gave a smaller deposit of active ingredient than obtained in the absence of additive, while 20% molasses gave a greater deposit, with either formulation. Molasses had an adverse effect on some properties of the spray mixtures, which resulted in lower deposits when spraying was done at high humidity in the laboratory. This effect was offset when spraying was done at lower humidity in the field, because molasses improved the impaction of droplets by increasing their density and by preventing the complete evaporation of small droplets.
The in‐vivo metabolism of propetamphos by insecticide‐resistant and susceptible strains of the housefly, Musca domestica
Authors: Wells David S. , Motoyama Naoki , Dauterman Walter C.
Published: November 2006

The metabolism of propetamphos by insecticide‐resistant and susceptible houseflies, in vivo, was investigated. Two major pathways of propetamphos degradation were found. The first is the major route of detoxification for both resistant and susceptible strains at low doses and involves a hydrolysis of the P–O‐vinyl bond, ultimately resulting in the formation of carbon dioxide. The second major pathway involves conjugation. As the dose increases, so does the importance of this pathway. Those strains of houseflies with greater conjugative capacity are able to tolerate greater doses of propetamphos than those strains with lesser conjugative capacity. The properties exhibited by this conjugate are consistent with those of glutathione conjugates. This is further supported by a parallel between reported values of glutathione S‐transferase activity in the houseflies tested and tolerance to propetamphos.
Teratogenic effects of the fungicide benomyl on posterior segmental regeneration in the earthworm, Eisenia fetida
Authors: Zoran Mark J. , Heppner Thomas J. , Drewes Charles D.
Published: November 2006

Earthworms, Eisenia fetida, were treated by surface exposure to the fungicide benomyl at various stages of posterior segmental regeneration. Teratogenic effects of benomyl were observed when worms were treated 7–11 days after amputation (i.e. during the normal period of segmental replication), but not during days 1–5, 13–17, or 19–23. Teratogenic effects included a reduction in the number of regenerated segments, an increased frequency of segmental groove anomalies, and a variety of monstrosities. The effects of benomyl treatment on the number of regenerated segments and frequency of anomalies were dose‐dependent within a narrow concentration range (approximately 0.2–5.0 mg litre−1); at higher concentrations (e.g. 25 mg litre−1) teratogenic effects were less frequent because the onset of segmental delineation was delayed until well after exposure. Non‐invasive electrophysiological recordings from treated worms indicated that functional integrity of giant nerve fibre conduction pathways was established in all anomalously regenerated tail segments, except in a two‐tailed monstrosity. The evidence supports the hypothesis that these teratogenic effects derive from an antimitotic mode of action of benomyl on segmental regeneration.
Fungicidal activity of 2‐(1‐alkenyl)‐3‐hydroxy‐1,4‐naphthoquinones and related compounds
Authors: Jacobsen Niels , Wengel Anita
Published: November 2006

The fungicidal activity of a series of 2‐(1‐alkenyl)‐3‐hydroxy‐1,4‐naphthoquinones and their acetates has been assessed against various fungi in vitro and against others, notably powdery mildews, in vivo, and the activity compared with that of analogous compounds bearing saturated side chains. Several of the compounds demonstrated a broad spectrum of activity in vitro. Whereas the presence of α‐unsaturation in the side chain is essential for the in‐vitro activity against the non‐obligate fungi tested, it is of virtually no importance for the curative effect against Erysiphe graminis on barley. Only the corresponding acetates had activity against the latter pathogen.
Residues of dalapon and TCA in sediments and irrigation water
Authors: Bowmer Kathleen H.
Published: November 2006

When dalapon and TCA are used for the management of aquatic weeds in irrigation distribution systems, they are often applied to established stands of Typha spp. and Phragmites australis in autumn or early winter, after draining water from the system. It has been assumed that the herbicides would dissipate from the sediments within 6 weeks, so that water supplies could be safely restored. In field experiments the decay of dalapon and TCA in sediments followed the classical pattern for a microbially mediated process, with a slow lag‐phase, followed by a rapid phase of decline, but not to completion. Particularly for TCA, there was a final slow phase in which residues were sufficient to contaminate eluting water at concentrations much greater than the legally prescribed tolerance, even when the interval between herbicide treatment and water re‐supply was more than 6 weeks. Although the overall pattern of dissipation in the sediment was similar for the two herbicides, concentrations of TCA were higher than those of dalapon in the elution water, probably reflecting differences in herbicide mobility and elution efficiency. Dye tracers were used in three field experiments to investigate the efficiency of herbicide elution and carryover of contaminated water when canals were filled to capacity, drained and refilled. Together with the rate of dissipation from sediments, canal topography and draining efficiency determined the safety of the elution process in removing surplus residues before re‐supply of water for irrigation. In large‐scale management operations, where the dissipation interval was only 17‐19 days, the TCA was eluted from the sediment into flowing water in proportion to the square root of time, giving average concentrations over 3 days of discharge of more than 0.4gm−3. Ideally, the interval between spraying and water re‐supply should be extended beyond 6 weeks. Alternatively, herbicide use should be restricted, or provision made for elution of surplus residues and disposal of contaminated water to waste, or onto tolerant crops or fallow land.
A note on the bimodal concentration response of Pythium aphanidermatum to carboxin and carbendazim
Authors: Panwar Roopali , Singh Rama S. , Singh Uma S.
Published: November 2006

The concentration/respone curve for carboxin and carbendazim against mycelial growth of Pythium aphanidermatum measured in vitro is bimodal, suggesting the involvement of more than one concentration‐dependent site of action.
High resolution g.l.c. specifications for plant spray oils
Authors: Furness Geoffrey O. , Walker David A. , Johnson Paul G. , Riehl Louis A.
Published: November 2006

High resolution g.l.c. chromatograms of a series of reference plant‐spraying oils were used for the development of proposed g.l.c standards for spraying oils in Australia. The mean size and size‐range of molecules in the oils have been specified in relation to carbon number positions for reference n‐paraffins. Problems with reproducibility and precision with reduced pressure distillation (10 mm Hg) of plant‐spraying oils have been demonstrated and discussed.
Synthesis and insecticidal activity of lipophilic amides. Part 6: 6‐(disubstituted‐phenyl)hexa‐2,4‐dienamides
Authors: Elliott Michael , Farnham Andrew W. , Janes Norman F. , Johnson Diana M. , Pulman David A.
Published: November 2006

By using a phosphonate containing an N‐(2,2‐dimethylpropyl) instead of an N‐(2‐methylpropyl) group, rearrangement during the Wadsworth‐Emmons condensation step was restricted to an acceptable level even with products from disubstituted phenylacetaldehydes. Previous results had shown that this change in N‐group did not alter insecticidal activity drastically, so structure‐activity relationship conclusions could be drawn from both series in combination. The presence of methyl groups on the phenyl lowered activity, confirming results in the mono‐substituted series, so attention was directed primarily to the numerous possible di‐halo combinations. Many were active, especialty those with 3,4 or 3,5 substitution patterns, but beyond this no simple correlations could be detected relating position or nature of substituents to activity. Varying both the phenyl substituents and amine group gave results approximately in agreement with additivity principles.
Permethrin treatments in canadian forests. Part 1: Impact on stream fish
Authors: Kingsbury Peter D. , Kreutzweiser David P.
Published: November 2006

The effects of permethrin on native and caged fish when aerially applied directly to forest streams at dosages between 8.8 and 70 g ha−1 were studied between 1976 and 1981. None of the applications caused mortality of caged or native fish in streams. Trout and salmon diets were altered by the treatments due to effects on fish food organisms. The duration of the effects varied from several months to over a year with increasing dosage. Reductions in salmonid growth rates and reductions in fish densities in treated areas, presumably due to emigration, were documented following severe impacts on aquatic invertebrates in salmon nursery streams. Growth rates and population densities both recovered within four months after treatment.
The photodegradation of parathion and chlormephos
Authors: Buckland Simon J. , Davidson R. Stephen
Published: November 2006

Irradiation (∼350 nm) of oxygenated acetonitrile solutions of parathion containing sensitisers such as benzoin and α‐dicarbonyl compounds leads to oxidative desulphurisation at phosphorus, producing paraoxon in reasonable yield. Other degradation reactions also occur, probably as a result of the presence of the 4‐nitrophenyl group in parathion. Under similar irradiation conditions, chlormephos is desulphurised at both the thionate and thiolate moiety. The reactions are rationalised as occurring via peroxy radicals which are generated from the sensitisers. Reaction was not observed when dyes, e.g. rose bengal, were used as sensitisers, which accords with the view that thionates and thiolates are not reactive towards singlet oxygen.
Physico‐chemical factors affecting uptake by roots and translocation to shoots of weak acids in barley
Authors: Briggs Geoffrey G. , Rigitano Renê L. O. , Bromilow Richard H.
Published: November 2006

The uptake from solution of maleic hydrazide, flamprop and a series of phenoxyacetic acids by roots, and their subsequent translocation to shoots, was measured in barley. Both uptake and translocation increased as the pH of the solution decreased, the magnitude of the change varying amongst the chemicals tested. Uptake by roots could be accounted for by the ion‐trap mechanism, which assumes that entry of the chemicals occurs largely by passive diffusion of the undissociated form of the acids, with passage of the anions across the cell membranes being very slow. The ratio of the permeability of the cell membranes to the undissociated and dissociated forms of the acids was estimated from the accumulation in roots, and in the phenoxyacetic acid series this ratio was maximal (4×105) for compounds of intermediate lipophilicity. Maleic hydrazide and flamprop had much lower ratios, 1.8×102 and 103 respectively; the value for flamprop was much less than for phenoxyacetic acids of similar lipophilicity, such as 2, 4‐ dichlorophenoxyacetic acid, indicating that lipophilicity may not be the sole factor determining the behaviour of weak acids in plants. Translocation to shoots was approximately proportional to the chemical concentrations in the roots.
Characterization of the structure‐activity relationship of kdr and two variants of super‐kdr to pyrethroids in the housefly (Musca domestica L.)
Authors: Farnham Andrew W. , Murray Alistair W. A. , Sawicki Roman M. , Denholm Ian , White Jean C.
Published: November 2006

Structure‐activity relationships (SARs) for 10 pyrethroids against susceptible, kdr and super‐kdr strains of houseflies (Musca domestica L.) were investigated by Principal Components Analysis. In the three strains with kdrLatina' all only slightly to moderately (2.6 to 26‐fold) resistant to pyrethroids, no correlation between the structure and Levels of resistance could be discerned. In flies with super‐kdr, SARs were influenced by the nature of the alcoholic portion of the ester. Resistance was strongest to esters of a‐cyano‐3‐phenoxybenzyl alcohol (74 to 430‐fold) and to permethrin (48 to 55‐fold). It was weak (6.2 to 11‐fold) to cyclopentenone derivatives, being barely stronger than for flies with kdr (2‐6 to 6.3‐fold). Two variants of super‐kdr (3D and A2) were distinguished on the basis of their differential response to esters of 5‐benzyl‐3‐furylmethanol. It is presumed that kdrLatina, super‐kdrA2 and super‐kdr3D form an allelic series in which kdrLatina represents ground level insensitivity, and the two super‐kdrs the progressive extension of strong resistance to more types of ester. The strong differences in resistance to different pyrethroid esters by super‐kdr flies provides scope for improving management of resistance to pyrethroid insecticides and for modifying the SAR of pyrethroids to favour weak resistance.
Determination and persistence of imazalil in post‐harvest‐treated apples during cold storage
Authors: Cano Maria P. , De la Plaza Josê L. , Muñoz‐Delgado Luis
Published: November 2006

A method to determine imazalil (allyl 1 ‐(2, 4‐dichlorophenyl)‐2‐imidazol‐ 1‐ylethyl ether) on apples using high performance liquid chromatography is described. After harvest, fruits were immersed in an aqueous suspension (1 g litre‐1) and cold stored (0‐2°C) at 85‐90% r.h. Samples were taken monthly and imazalil was determined in the peel, outer pulp, inner pulp and on whole fruit. Residues were 3.8‐4.9 mg imazalil kg‐1 and decreased during storage. Most imazalil was found on the peel and amounts in the pulp decreased toward the core.
Studies on octylphenoxy surfactants. Part 2: Effects on foliar uptake and translocation
Authors: Stevens Peter J. G. , Bukovac Martin J.
Published: November 2006

The effects of octylphenol (OP) and four of its ethoxylated derivatives on uptake into, and distribution within, maize leaf of 2‐deoxy‐glucose (2D‐glucose), atrazine and o, p′‐DDT are reported. The surfactants and OP (2 g litre−1 in aqueous acetone) increased the uptake, at both 1.5 and 24 h, of the three model compounds (applied at 1 g litre−1) having water solubilities in the g, mg and μg litre−1 ranges. The uptake of 2D‐glucose was positively correlated with the hygroscopicity of the surfactants. The uptake of DDT and atrazine increased with the uptake of the surfactants, being inversely related to their hydrophile:lipophile balance (HLB). Uptake of 2D‐glucose and atrazine was enhanced at high humidity, the relative enhancement for atrazine increasing with increasing ethylene oxide (EO) content of the surfactants. A significant proportion of the atrazine and DDT entering the leaf was recovered from the epicuticular wax, the amount of atrazine recovered from the wax increasing with the EO content of the surfactants. The proportion of the surfactants taken up which was recovered from the epicuticular wax was minimal at an EO content of 12.5–16 mole equivalents. The appearance of the deposits on the leaf surface differed markedly among the surfactants, with similar trends for all three chemicals and without visible evidence for infiltration of the stomatal pores. The total quantities of glucose and atrazine translocated were increased by all surfactants but that of DDT was not, despite increases in uptake of up to 7.5‐fold. Relative translocation (export from treated region of leaf as a percentage of chemical penetrating beyond the epicuticular wax) was reduced in all cases in the presence of surfactant. Up to 30% of the applied [14C]chemicals was not recovered from the treated leaf after 24 h. The reduced recovery of 2D‐glucose, but not that of atrazine and DDT, was largely attributable to movement out of the treated leaf, with approximately 70% of the chemical taken up being translocated basipetally. Loss of atrazine and DDT was a result of volatilisation. There was no evidence that either [14C]2 D‐glucose or [14C]atrazine was metabolised to [14C]carbon dioxide.
Influence of temperature on physical properties of non‐aqueous pesticide formulations and spray diluents: Relevance to u.l.v. applications
Authors: Sundaram Alam
Published: November 2006

The viscosity, surface tension and volatility of a range of ultra‐low‐volume (ULV) spray diluents and pesticide formulations were measured at 5°C and 20°C. For u.l.v. application of 1.0 to 1.5 litre ha−1 through conventional boom and nozzle systems or rotary (Micronair) atomisers, it is concluded that the spray medium should have a viscosity of ⩽30 mPa s at 20°C. The surface tension values covered only a narrow range and showed little temperature dependence. There was no clear optimum and all surface tensions within the range measured would appear to be acceptable for ULV applications. The volatility factor, 1/(A.T1/2), where A represents the percentage of non‐volatile material in the spray mixture and T1/2, the half‐life (minutes) of evaporation, should be <40 times; 10−5.
Triadimenol soil residues following tobacco seedbed drenches to control sore shin of transplants
Authors: Cole James S. , Zvenyika Zvenyika , Toet Leendert
Published: November 2006

Triadimenol residues were monitored during a four‐year period in sandy soil following annual drenches (2 litre m−2) over tobacco seedbeds and in rotatinos with one or two years of Rhodes grass (Chloris gayana) followed by tobacco. Residues in the 0–10 cm zone were proportional to rates of application and did not accumulate during the four‐year period. Maximum concentration two months after treatment was found in the 5–7–5 cm zone. They inhibited the emergence and growth of Rhodes grass, though not permanently. Recolonization of the soil by Rhizoctonia solani was delayed and there was little effect on emergence and growth of tobacco seedlings.
Influence of physical properties on droplet size spectra and deposit patterns of two mexacarbate formulations, following spray application under laboratory and field conditions
Authors: Sundaram Alam , Sundaram Kanth M. S. , Leung John W. , Holmes Stephen B. , Cadogan Beresford L.
Published: November 2006

The influence of viscosity, density, surface tension, volatility and apparent viscosity‐shear rate relationship on droplet‐size spectra and deposit characteristics of two mexacarbate (4‐dimethylamino‐3,5‐xylyl methylcarbamate) formulations, one oil‐based and one water‐based, was studied following spray application under laboratory and field conditions. The oilbased formulation had a higher viscosity, a higher apparent viscosity at high shear rates and a lower volatility than the water‐based formulation; application through rotary atomisers gave larger droplet sizes, more droplets cm−2 and deposits of the active ingredient ha−1 than those from the water‐based formulation in both the laboratory and field studies. Both formulations had similar surface tensions and densities and, therefore, the contribution of these properties to droplet‐size spectra could not be determined. Among the three properties (viscosity, apparent viscosity‐shear rate relationship and volatility), volatility contributed most to the deposit patterns of the two formulations.