bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of insecticide resistance in the peach‐potato aphid, Myzus persicae (Sulzer)
Authors: Sawicki Roman M. , Devonshire Alan L. , Payne Roger W. , Petzing Stephanie M.
Published: November 2006

Anholocyclic Myzus persicae (Sulz.) from the glasshouse and field can be classified into six variants, each with a characteristic carboxylesterase activity and consequent resistance to carbamate and organophosphorus insecticides. Overlapping activity distributions prevent unequivocal identification of an individual from measurements of its enzyme activity, but this may be done by cloning and measuring the frequency distribution of the enzyme activity in its progeny. Although each of the four lowest esterase variants has a frequency distribution with a single peak, only the susceptible (USLL) is best described by a single Normal distribution. Those of the other three clones (MSIG, French R and T1V) correspond better with two Normally‐distributed components. However, these are not well separated and the lower component accounts for only 10‐25% of the individuals. The very resistant clones from glasshouses have higher mean activities but with very broad distributions covering the whole range observed in this aphid. These broad distributions have peaks corresponding to those of the less resistant variants and arise from the appearance at each generation of a small proportion of individuals with much less active enzyme than their parents. Careful monitoring of the changes in activity between parents and offspring of the most resistant variant (clone G6) showed that complete loss of resistance can occur either in a single step or over several generations, and that below a threshold value, reversion to higher levels is very rare. Such reversion could only be detected by selection, with insecticide, of large clonal populations from an individual that had lost activity. High esterase activity was not stabilised by breeding for 16 generations only from individuals with high esterase activity, and is probably maintained in glasshouses by continuous exposure to insecticides. Spontaneous loss of esterase activity and resistance was observed only in glasshouse populations.
The bromination of highly halogenated chrysanthemic acid analogues
Authors: Bentley Philip D. , Cheetham Rex , Huff Roger K. , Swanborough Joe
Published: November 2006

(Z)‐cis‐ and (Z)‐trans‐3‐(2‐chloro‐3,3,3‐trifluoroprop‐1‐enyl)‐2,2‐dimethylcyclo‐propanecarboxylic acids react with bromine under radical conditions predominantly to open the cyclopropane ring; the stereochemistry and reactions of the dibromides thus formed are described.
Recent topics in the chemistry of synthetic pyrethroids containing certain secondary alcohol moieties
Authors: Matsuo Takashi , Nishioka Toshio , Hirano Masachika , Suzuki Yukio , Tsushima Kazunori , Itaya Nobushige , Yoshioka Hirosuke
Published: November 2006

Four important classes of synthetic pyrethroids containing certain secondary alcohol moieties, namely the α‐cyano‐3‐phenoxybenzyl esters, the analogous α‐ethynyl esters, 1‐(3‐phenoxyphenyl)prop‐2‐ynyl esters and 2‐methyl‐4‐oxo‐3‐(prop‐2‐ynyl)‐cyclopent‐2‐enyl esters and their most active isomers, are introduced with essential descriptions of synthetic pathways, optical resolution and determination of absolute configuration. The relationship between stereochemistry and the biologically active enantiomers of esters formed from the major secondary alcohols is discussed.
The vinylogous relationship in some pyrethroids
Authors: Farooq Saleem
Published: November 2006

Attention is drawn to a vinylogous relationship between the structure of certain biologically‐active pyrethroids. A series of racemic α‐cyano‐3‐phenoxybenzyl 2‐(2,2‐dichlorovinyl)‐1‐phenylcyclopropanecarboxylates, based on this relationship, were synthesised and were found to be only moderately toxic to Musca domestica, Spodoptera littoralis and Leptinotarsa decemlineata.
A novel series of O,O‐diethyl O‐(1,3‐disubstituted‐1,2,4‐triazol‐5‐yl) phosphorothioates. Part II. Quantitative structure–activity relationships
Authors: Gozzo Franco , Masoero Marcella , Quadrelli Luciana , Zagni Angela
Published: November 2006

The in‐vivo toxicity data of 33 O,O‐diethyl O‐(1‐alkyl‐3‐R″‐1,2,4‐triazol‐5‐yl) phosphorothioates, reported in Part I of this series, were subjected to multiregression analyses for the following organisms: Leptinotarsa decemlineata (larvae), Macrosiphum euphorbiae (aphids), Culex pipiens (adults), Spodoptera littoralis (larvae) and the rat. The activities were found to depend mainly on the steric parameters of R″, these being best expressed by the values L, B1 and B4 of the computer program STERIMOL. It was shown that there were different steric requirements for each species and these are discussed. The predictive values of the best equations were also estimated.
An analytical procedure for bromoxynil and its octanoate in soils; persistence studies with bromoxynil octanoate in combination with other herbicides in soil
Authors: Smith Allan E.
Published: November 2006

A method is described for the analysis of the herbicide bromoxynil and its octanoate in soils. Following extraction with aqueous acidic acetonitrile, the octanoate was separated from the phenolic bromoxynil by solvent partitioning. The ester and the phenol were assayed by gas‐liquid chromatography without further modification or preparation of a derivative. Recoveries in excess of 93% were obtained from soils treated with the phenol and the ester at levels of 0.5 or 0.1 μg g−1. The persistence of bromoxynil octanoate applied at a rate of 3 μg g−1 was studied in the laboratory on a heavy clay and a sandy loam at 85% of field capacity moisture and 20°1°C, both alone and in the presence of 2,4‐D (2 μg g−1); MCPA (2 μg g−1); MCPA+asulam (both at 2 μg g−1); and MCPA+difenzoquat (both at 2 μg g−1). In each soil there was a rapid conversion of bromoxynil octanoate to the free phenol, which then underwent a rapid degradation, so that after 7 days, over 90% of the original treatment had disappeared. There appeared to be no effect on bromoxynil breakdown by any of the herbicides added in combination. Small field plots were treated, in early May 1977 and 1978 at two locations in Saskatchewan, with a combination of commercial formulations containing asulam, bromoxynil octanoate, and MCPA at rates of 1 kg ha−1 each. After 10 weeks the plots were sampled and analysis showed that in all cases, no asulam, bromoxynil, or bromoxynil octanoate could be extracted from the top 10 cm of soil.
Fungi in stored barley treated with systemic fungicides
Authors: Niles Eric V.
Published: November 2006

Six fungicides (benomyl, carbendazim, fuberidazole, thiabendazole, thiophanate and thiophanate‐methyl) were applied as dusts to barley in concentrations of 100, 1000 and 10 000 μg g−1 and the barley then stored at 20°C and 90% relative humidity for 60, 105 and 150 days, respectively. Fungal development during storage was assessed by counting the visible patches of developing mould and by dilution plating. None of the fungicides completely prevented fungi developing but for the period up to 60 days, all provided a degree of control that was generally greatest for the highest concentration of fungicide. Benomyl was the most effective of the fungicides but no clear pattern was established for the others. Of the fungi that developed, species of Aspergillus and Penicillium accounted for 94% of the total count.
Fenitrothion plus (1R)‐phenothrin, and pirimiphos‐methyl plus carbaryl, as grain protectant combinations for wheat
Authors: Bengston Mervyn , Connell Melville , Davies Richard A. H. , Desmarchelier James M. , Phillips Mervyn P. , Snelson Jack T. , Sticka Rex
Published: November 2006

Duplicate field trials were carried out on bulk wheat in commercial silos in Queensland and New South Wales. Laboratory bioassays on samples of treated grain at intervals over 9 months, using malathion‐resistant strains of insects, established that treatments were generally effective. Fenitrothion (12 mg kg−1)+ (1R)‐phenothrin (2 mg kg−1) was more effective than pirimiphos‐methyl (6 mg kg−1) + carbaryl (10 mg kg−1) against Sitophilus oryzae (L.) and Ephestia cautella (Walker); the order of effectiveness was reversed for S. granarius (L.). Against Rhyzopertha dominica (F.), Tribolium castaneum (Herbst), T. confusum Jackquelin du Val and Oryzaephilus surinamensis (L.), both treatments effectively prevented the production of progeny. The order of persistence was pirimiphos‐methyl> (1R)‐phenothrin>carbaryl or fenitrothion. During processing from wheat to white bread, residues were reduced by 98% for carbaryl, >44% for (1R)‐phenothrin, 98% for fenitrothion and 85% for pirimiphosmethyl.
Gamma‐HCH in eggs and poultry arising from exposure to thermal vaporisers
Authors: Bernard Fishwick F. , Hill Edward G. , Rutter Irene , Warre Peter R.
Published: November 2006

Levels of gamma‐HCH have been determined in poultry tissue and eggs taken from poultry houses in which thermal vaporisers were operated. During continuous operation for 14 months, residue levels of gamma‐HCH in both substrates were related closely to changing levels of insecticide in the vaporiser; up to 46 mg kg−1 (on a fat basis) was found in tissue and up to 4.0 mg kg−1 (on a whole liquid basis) in eggs. Where the vaporisers were operated discontinuously, maximum levels were 6.7 mg kg−1 in tissue and 0.53 mg kg−1 in eggs.
The synthesis and insecticidal activity of carbamates of 2‐dialkylamino‐4‐nitrophenols
Authors: Baillie Alister C.
Published: November 2006

A description is given of the synthesis, acetylcholinesterase inhibition, insecticidal activity and field trial results with 2‐diethylamino‐4‐nitrophenyl dimethylcarbamate and related compounds.
Effect of short exposures to a high concentration on the subsequent toxicity of low concentrations of methyl bromide to diapausing larvae of the warehouse moth, Ephestia elutella (Hübner)
Authors: Bell Christopher H.
Published: November 2006

Ephestia elutella larvae in diapause were exposed at 25°C to methyl bromide at 12 mg litre−1 for 3.5 or 7.5 h and then immediately exposed to a lower concentration. The minimum effective concentration (that at which Haber's rule, concentration × time = k, a constant for mortality, still applied) was about 3 mg litre−1 in tests with no previous exposure toa high concentration, but it was about 2.5 mg litre−1 for individuals surviving a 3.5 h exposure to 12 mg litre−1, and was about 1.6 mg litre−1 for those surviving a 7.5 h exposure to 12 mg litre−1. These exposures to 12 mg litre−1, respectively, killed 2–20% and 50–75% of larvae exposed, and hence the smaller the proportion of survivors of exposure to a high concentration, the lower the minimum effective concentration needed against them. Thus the low concentration persisting at the end of a practical fumigation should contribute significantly to the success of the treatment and be much more effective than any similar low concentration present soon after the introduction of gas.
Effects of pesticides on 1,3‐β‐glucanase and urease activities in soil in the presence and absence of fertilisers, lime and organic materials
Authors: Lethbridge Gordon , Bull Alan T. , Burns Richard G.
Published: November 2006

The effect of four herbicides (2, 4‐D, di‐allate, benzoylprop‐ethyl and glyphosate) and one insecticide (malathion) on 1, 3‐β‐glucanase and urease activities in soil was investigated in the laboratory. Concentrations equivalent to five times the recommended field application rates of the pesticides, applied as their formulations, had no effect on the activity of either enzyme, under a variety of incubation conditions, which included various moisture regimes and soil treatments. The soil enzyme systems could only be disrupted by unrealistically high dosage rates of the active ingredients (0.1–1.0 g kg−1 of soil), Thus 1, 3‐β‐glucanase activity was enhanced by 2, 4‐D, inhibited by di‐allate, benzoylprop‐ethyl and malathion, but unaffected by glyphosate; whereas urease activity was inhibited by 2, 4‐D, but unaffected by di‐allate, benzoylprop‐ethyl and glyphosate.
Simultaneous estimation of bioresmethrin and piperonyl butoxide by gas‐liquid chromatography with chemical‐ionisation mass spectrometry
Authors: Cave S. Jane
Published: November 2006

A technique using gas‐liquid chromatography combined with chemical‐ionisation mass spectrometry is described for the simultaneous quantitative measurement of bioresmethrin and piperonyl butoxide. It is sensitive to 0.2 ng bioresmethrin and 2 ng piperonyl butoxide. The amounts of these compounds, in extracts of 50‐g samples of laboratory‐fortified wheat, were determined.
Spider mite webbing. Part IV: The effect of acaricides on spinning by the carmine spider mite Tetranychus cinnabarinus (boisduval)
Authors: Gerson Uri , Aronowitz Arieh
Published: November 2006

Cyhexatin, dienochlor and four experimental acaricides, U‐25322 (1‐benzoyl‐3‐phenylhydrazine), U‐27415 1‐benzoyl‐3‐(2, 4, 6‐trichlorophenyl)hydrazine, U‐42558 [N1(4‐chloro‐o‐tolyl) N2‐methyl‐N1‐(phenylthio)formamidine], and U‐42564 [N2‐methyl‐N1‐(phenylthio)‐ N1‐(2, 4‐xylyl)formamidine], at 125 mg litre‐1, induced spindown by the carmine spider mite, Tetranychus cinnabarinus (Boisduval). Cyhexatin caused the largest number of mites to spin‐down, dienochlor the least. Spinning occurred only during the first 6 h after treatment. Mites spun the same average length of threads in response to all compounds. The pattern of spin‐down was even and similar for all the compounds except dienochlor for which it was sporadic. Acaricide‐induced spin‐down is postulated to be an ‘all‐or‐nothing’ reaction.
Determination of carbofuran residues and metabolites in plant material
Authors: Tannock James , Wessels Carol L.
Published: November 2006

An improved method for the analysis of carbofuran residues and its metabolites in plant material has been developed. Critical evaluation of previously published methods has enabled the elimination of unnecessary procedures, and practical difficulties have been overcome or minimised without loss of sensitivity. Separate extraction of bound and non‐bound residues is followed by clean‐up by coagulation, preparation of a derivative with 1‐fluoro‐2,4‐dinitrobenzene, and gas‐liquid chromatography using a thermionic nitrogen‐selective detector system. The method can be used in general screening for carbamates as well as analysis for specific carbamate pesticide residues.
Kinetics and products of the hydrolysis of 3,4‐dihydroprecocene I 3,4‐epoxide in aqueous organic solvents
Authors: Hamnett Anthony F. , Ottridge Anthony P. , Pratt Grahame E. , Jennings Richard C. , Stott Katherine M.
Published: November 2006

The hydrolysis of 3, 4‐dihydroprecocene I 3, 4‐epoxide (3, 4‐dihydro‐7‐methoxy‐2, 2‐dimethyl‐3, 4‐epoxy‐2H‐benzo[b]pyran), the putative ultimate cytotoxin of the insect growth regulator precocene I (7‐methoxy‐2, 2‐dimethyl‐2H‐benzo[b]pyran), has been studied and found to exhibit first‐order kinetics [k = 0.17 s−1 in 10 mm‐phosphate buffer pH 7.0, containing 1, 4‐dioxane (1 + 1 by volume), ionic strength 0.1]. Plots of log k versus pH, and k versus buffer concentration, suggest that the reaction is subject to both specific and general acid catalysis. High‐performance liquid chromatography showed the reaction products to be predominantly the corresponding stereoisomeric diols (3, 4‐dihydro‐7‐methoxy‐2, 2‐dimethyl‐2H‐benzo[b]pyran‐3, 4‐diol), the trans : cis ratio of which varied from 1.8: 1 to 2.2: 1 but was constant over the pH range 6‐8, at a given buffer concentration. The results indicate that acid‐catalysed hydration of 3, 4‐dihydroprecocene I 3, 4‐epoxide is an SN1 reaction, involving a trigonally hybridised carbocation at C4, even at physiological pH. Similar studies on 3, 4‐dihydroiso‐precocene I 3, 4‐epoxide (3, 4‐dihydro‐6‐methoxy‐2, 2‐dimethyl‐3, 4‐epoxy‐2H‐benzo‐[b]pyran), a biologically inactive isomer of 3, 4‐dihydroprecocene I 3, 4‐epoxide suggest that an SNI mechanism also contributes to its hydrolysis, but the rate constant is 4000 times lower than that for 3, 4‐dihydroprecocene I 3, 4‐epoxide. Knowledge of the reactivity and mechanism of reaction of such compounds forms an important part of the basis for rational prediction of biological activity in precocene analogues, and hence their possible use as pest control agents.
The kinetics of insecticide action. Part II: The relationship between the pharmacokinetics of substituted benzyl (1RS)‐cis, trans‐chrysanthemates and their relative toxicities to mustard beetles (Phaedon cochleariae fab.)
Authors: Ford Martyn G. , Greenwood Richard , Thomas Peter J.
Published: November 2006

A mathematical model describing insect pharmacokinetics has been applied to data describing the penetration and elimination of a series of pyrethroid analogues [the methylbenzyl (1 RS)‐cis, trans‐chrysanthemates], applied to mustard beetles. The three parameters of the model (kp, ke and λ) have been estimated for each compound. The influence of chemical structure on pharmacokinetics, investigated using canonical correlation analysis, is discussed in relation to relative toxicity and knockdown action. In general, physicochemical properties which result in a slow flow of insecticide through the insect are associated with high toxicity. A large proportion (84%) of the variation in relative toxicity has been explained by resistance to elimination (1/ke), implying that exposure of the site of action to insecticide is related to the total integral IM2 for material (M2) inside the insect. The remaining variation has been attributed to differences in behaviour at receptor sites. An optimum partition value (Δπ0 ≈ 1.6) seems necessary for maximum pharmacodynamic activity in this series of compounds.
Extensive pilot use of the grain protectant combinations, fenitrothion plus bioresmethrin and pirimiphos‐methyl plus bioresmethrin
Authors: Desmarchelier James , Bengston Mervyn , Connell Melville , Henning Ronald , Ridleye Edward , Ripp Eric , Sierakowski Charles , Sticka Rex , Snelson Jack , Wilson Arnold
Published: November 2006

Each of the combinations, bioresmethrin (1 mg kg−1) plus pirimiphos‐methyl(6 mg kg−1) or fenitrothion (12 mg kg−1), was applied in 1976 to grain in 21 commercial storages. Grain condition and protectant residues were regularly monitored. Three storages became infested with Rhizopertha dominica (F.), but all storages remained free of other insect species. In two of the three infested storages, application of protectant was uneven, and the third became infested only after 8 months of storage. Despite some variations in recovered residues between sites, the mean residue levels were accurately described by predictive models. Falls in temperature during storage varied considerably, and were related to factors other than climate and bin size. There was a marked effect by aeration with ambient cold air on both the grain temperature and the rate of loss of residues. Results of collaborative studies on the determination of residues indicate a need for regular check programmes of analysis, and confirm previous conclusions that residues of fenitrothion and pirimiphos‐methyl can be accurately and conventionally determined.
The influence of soil and other physical factors on the antifungal activity of carbendazim against Rhizoctonia solani
Authors: Hans Jatender K. , Tyagi Prem D. , Kataria Hans R. , Grover Rajendra K.
Published: November 2006

The inhibition of the growth of Rhizoctohia solani in vitro by carbendazim was maximal at 20°C and at pH 8. In pot tests using mung bean, maximum protection against ‘damping‐off’, caused by R. solani, was obtained when seeds were treated with carbendazim. at 1 g a. i. kg−1 (as a wettable powder) and sown in river sands of pH 7 and 8, kept at a 20°C. Better disease control was obtained in soils kept moist by frequent watering than in soils under water stress. Disease control was best in sandy soil and least in clay loam. The implications of these results, for the antifungal efficacy of carbendazim under diverse soil conditions, are discussed.
The diastereomeric ratio in the triadimenol produced by fungal metabolism of triadimefon, and its role in fungicidal selectivity
Authors: Gasztonyi Maya
Published: November 2006

The ratio of the two diastereomeric forms of triadimenol, produced by the reduction of triadimefon in various fungi, was studied. The reduction of triadimefon in fungi seems to be a concentration‐dependent process, the virtual irreversibility of which is proved. Not only the degree of triadimefon reduction, but also the ratio of the triadimenol diastereomers produced, was characteristic for each of the fungal species. A direct correlation, between the production of the more active diastereomeric form and the sensitivity of the fungal species to triadimefon, was observed.
The interaction between bactericidal chemicals and the wound healing process of potato tuber tissue
Authors: Harris Royston I.
Published: November 2006

In‐vitro tests of dichlorophen against Erwinia carotovora, vars. atroseptica and carotovora, have shown good antibacterial activity; in‐vivo tests on potato tubers, however, showed poor control of bacterial soft rotting. Under aerobic or near anaerobic conditions, wounded potato tubers dipped in dichlorophen showed significant increases in soft rotting over water‐treated tubers. Under near anaerobic conditions, neither dichlorophen‐dipped nor water‐dipped tubers showed evidence of wound healing. However, when incubated aerobically, a distinct wound barrier was evident in the water‐dipped but not the dichlorophen‐dipped tubers. To investigate the possibility that dichlorophen was inhibitory to the initiation of wound healing, an image analysing computer was used to measure the accumulation of fluorescent products in the walls of sectioned tuber tissues treated with dichlorophen. Dichlorophen treatment resulted in very low levels of fluorescence, indicating little phenolic accumulation in the walls. Other bactericides also decreased fluorescence to some extent.
Fungitoxicity of hydroxy‐ and methoxy‐substituted phenyl‐ and naphthyl‐benzofurans, phenylbenzo[b]thiophenes and phenylindoles
Authors: Chamberlain Keith , Carter Geoffrey A.
Published: November 2006

The antifungal activities in vitro of 43 methoxy‐ and hydroxy‐substituted aryl‐benzofurans, phenylbenzo[b]thiophenes and phenylindoles were compared with those of the unsubstituted compounds. Monohydroxy derivatives were usually the most fungitoxic against Alternaria brassicicola, Botrytis cinerea, Septoria nodorum, Cladosporium cucumerinnum, Fusarium culmorum and Uromyces fahae but the precise effect of substitution upon activity varied with the nature of the parent aryl‐hetocyclic compound, with the position in the molecule, and with the presence of other substituents. Fangitoxicity did not correlate significantly with the partitioning properties of the molecuie as measured by reversed‐phase thin‐layer chromatography.
The effective dominance of resistance genes in relation to the evolution of resistance
Authors: Wood Roger J. , Mani Gopalakrishnan S.
Published: November 2006

Field selection for a rare insecticide resistance (R) gene can be substantially delayed if R is rendered effectively recessive [if all or most heterozygotes ( R + ) are killed by the field dosages] and if a representative sample (+ +, R +, RR) of the population is permitted to escape exposure. The relationship between heterozygote mortality and escape in influencing selection rates has been considered at various frequencies of R. The cases when mating precedes selection, and when selection precedes mating, have been calculated using computer simulations. It is concluded that when R genes are rare it is advantageous (a) to apply the highest possible doses of insecticide in such a form that all exposed insects pick up an amount sufficient to kill all or most heterozygotes, (b) to apply the insecticide to adults after they have mated, rather than to younger adults or to larvae, and (c) to ensure that the proportion of insects given the opportunity to escape contact is as high as practical considerations allow. Once resistance is obvious (when samples are brought into the laboratory for tests), the R gene frequency will have risen to a level which makes the suggested strategy no longer valuable. Alternative strategies are briefly discussed.
Initial pesticide residues in relation to vapour pressure
Authors: Ritcey Gwen , McEwen Freeman L. , Braun Heinz , Frank Richard
Published: November 2006

Field tests, in which several insecticides were applied at equal rates by ground sprayer to oats, rye and alfalfa, showed that residues 1 h after application were much lower for highly volatile compounds than for those of lower volatility. Varying the distance from spray release to target canopy from 10 to 40 cm did not significantly affect the deposits. Results indicate that applying insecticides with a vapour pressure greater than about 10−4 mmHg (20°C) in aqueous media is very inefficient.
Structure‐activity relationships in fungitoxicants related to triforine and chloraniformethan. Part IV: Evaluation of the predictive power of the Hansch analysis by the preparation and testing of further chloraniformethan analogues
Authors: Loeffler R. S. Thomas , Woodcock David , Carter Geoffrey A. , Johnson Diana M.
Published: November 2006

Seven chloraniformethan analogues, which were predicted, on the basis of the quantitative Hansch analysis performed previously, to be as active as the parent compound against barley powdery mildew (Erysiphe graminis), were prepared. Their activity as leaf sprays against E. graminis was much lower than that calculated using the regression equations, indicating that the Hansch analysis is not a suitable method for predicting fungitoxicity in this chloraniformethan series of compounds.
Depletion of residues of benzoylprop‐ethyl in soil
Authors: Bosio Pierre G. , Elgar Kenneth E. , Mathews Brian L. , Woodbridge Austin P. , Wright A. Neill
Published: November 2006

The depletion of residues of benzolyprop‐ethyl (I) and its hydrolysis product N‐benzoyl‐N‐(3,4‐dichlorophenyl)‐DL‐alanine (II) in soils is reported from various trials following applications of I to soil and crops at up to 3 kg ha−1. Quite rapid hydrolysis of I to II occurred in most soils and depletion of II followed. The total residue of I and II in the soil often initially increased, probably because of transfer of chemical from the crop to the soil, but the time for 50% disappearance of the total residue (I+II) was normally between 4 and 16 weeks. When four sites were treated for three successive years, carry‐over of residues was negligible in three sites and showed no progressive increase in the fourth.
Relative toxicities of phorate and some of its metabolites to Aphis fubae Scop
Authors: Ho Shuit H. , Galley D. John
Published: November 2006

An aqueous solution of bromine was used to oxidise 14C‐labelled phorate to its metabolites. A substantial amount of [14C]phorate sulphone (O,O‐diethyl S‐ethylsulphonyl[14C]methyl phosphorodithioate) with minute quantities of [14C]phorate sulphoxide (O,O‐diethyl S‐ethylsulphinyl[14C]methyl phosphorodithioate) and [14C]phoratoxon sulphoxide (O,O‐diethyl S‐ethylsulphinyl[14C]methyl phosphorothioate) were recovered using this method. Various concentrations of [14C]phorate and these toxic metabolites were individually incorporated in an artificial diet and fed to Aphis fabae Scop. Mortality was recorded after 48 h. The toxic fractions of the compounds were extracted from the diet and their radioactivity was measured to determine the dose unit. The aphids feeding on diet containing high concentrations of [14C]phorate sulphoxide and [14C]phoratoxon sulphoxide were seen wandering restlessly, which suggested that the acceptability of the diet had been changed by the presence of these metabolites. Phorate appeared to be the most toxic to the aphids, followed by phorate sulphone, phorate sulphoxide and phoratoxon sulphoxide in that order; the reasons for this are discussed.
Photochemical Degradation of Picloram
Authors: Gear James R. , Michel Joseph G. , Grover Raj
Published: November 2006

The rate of photochemical degradation of aqueous solutions of picloram under ultraviolet light was measured by five different methods of analysis. These were chosen to assay the loss of picloram, dechlorination, alteration or loss of the aromatic amino group, loss of aromaticity, and decarboxylation. The initial rate and mean rate of reaction were determined in each case, and their relationship to each other was used to assess the significance of that particular reaction to the overall degradation of picloram and its early degradation products. Results suggest that dechlorination is the major photochemical process, with decarboxylation, loss of aromaticity, and deamination all being significant subsequent reactions.
Transformation of the herbicides propanil and chlorpropham by micro‐algae
Authors: John S. , Wright L. , Maule Andrew
Published: November 2006

Two species of green algae and four of blue‐green algae hydrolysed the acylanilide herbicide propanil to the aniline derivative, 3,4‐dichloroaniline. Of the cultures tested, only the blue‐green alga Anacystis nidulans was shown to be capable of converting the phenylcarbamate herbicides propham and chlorpropham to the corresponding anilines. The green alga Ulothrix fimbriata was apparently unable to hydrolyse propanil or chlorpropham.
Antagonistic and synergistic activities of various chemicals on the toxicity of fenarimol to Aspergillus niduluns
Authors: de Waard Maarten A. , van Nistelrooy Johannes G. M.
Published: November 2006

A variety of chemicals were tested for their antagonistic, independent, or synergistic effect, on the toxicity of fenarimol to fenarimol‐sensitive and resistant strains of Aspergillus nidulans. The chemicals that antagonised fenarimol toxicity included natural lipids and non‐ionic surfactants; those with synergistic activity were anionic and cationic agents (including dodine), some conventional fungicides, hydrochloric acid, sodium hydroxide, and respiratory inhibitors. All these synergists also potentiated the toxicity of fenarimol to fenarimol‐resistant mutants of A. nidulans. In addition, resistance to fenarimol was negatively correlated with dodine sensitivity. Possible mechanisms of antagonism and synergism are discussed. The results may have implications, for fungicides that inhibit sterol biosynthesis, in respect of their efficacy to plant pathogens.
Uptake and residues of aldicarb in sugarbeet leaves
Authors: Dejonckheere Willy , Melkebeke Guy , Steurbaut Walter , Kips Renté H.
Published: November 2006

The breakdown of aldicarb and its oxidation products (the sulphoxide and the sulphone, aldoxycarb), under field conditions in 1976, were studied on three different types of soil (a sandy loam, a silt loam and a sandy clay loam that were normally cropped with sugarbeet). Residues were determined in leaves, stems, roots and soil, and related to aphid counts. Higher doses were needed on heavy soils in order to obtain a sufficient concentration in the leaves and thus provide an efficient treatment for aphid control. Weather conditions, especially rainfall, also affected the residue content. At harvest, the sugar beet tops used for fodder can contain residues which vary widely, depending on dosage, soil type and climatic conditions.
Genetic and biochemical studies of resistance to permethrin in a pyrethroid‐resistant strain of the housefly (Musca domestica L.)
Authors: Nicholson Russell A. , Sawicki Roman M.
Published: November 2006

One or more weak factors of resistance on autosome 2, and barely detectable resistance on autosome 3, confer moderate resistance to several pyrethroids (5–13‐fold) in the field‐collected Ipswich strain of houseflies. In these flies, which unlike other pyrethroid‐resistant strains lack kdr or super‐kdr, pyrethroid resistance probably developed in response to prolonged treatment of buildings for animals with pyrethrins synergised with piperonyl butoxide. Substrains, isolated genetically from Ipswich flies and with resistance only on autosome 2, degraded permethrin more rapidly than susceptible flies and produced larger amounts of very polar metabolites. In this, they differed from flies with kdr or super‐kdr which resembled susceptible flies in their metabolism of permethrin. NIA 16388 (propyl prop‐2‐ynyl phenylphosphonate) was a better synergist and reduced the metabolism of permethrin more than piperonyl butoxide in both the susceptible and resistant insects. The slight increase in synergism and minimal decrease in metabolism when piperonyl butoxide was applied with NIA 16388 indicated that the latter also inhibited detoxication that was sensitive to piperonyl butoxide.
Pesticide residues in foodstuffs in Great Britain; organochlorine pesticides, organophosphorus pesticides and fumigant residues in home‐produced and imported wheat
Authors: Bailey Sidney , Collins Geoffrey B. , Fishwick F. Bernard , Hart Harold V. , Horler David F. , Scudamore Keith A.
Published: November 2006

Residue levels of organochlorine pesticides, organophosphorus pesticides, fumigants and bromide were determined in home‐produced and imported wheat during the period October 1978 to April 1979. A total of 281 samples was analysed of which 133 contained low levels of carbon tetrachloride, 112 contained low levels of gamma‐HCH and 26 contained low levels of malathion. One sample contained a residue of carbon tetrachloride, and another a residue of 1,2‐dichloroethane, both of which were above the Codex Alimentarius guide‐line levels. No other residue approached the proposed Codex Alimentarius maximum residue limits.
Foliar residues and toxicity to Aphis citricola of three systemic insecticides applied to the soil in a citrus grove
Authors: Neubauer Ilan , Aharonson Nadav , Ishaaya Isaac , Raccah Benjamin , Soroksi Larisa
Published: November 2006

A study was made of the accumulation of aldicarb, ethiofencarb and dimethoate in citrus leaves and fruit; the toxicity of these insecticides to the spirea aphid (Aphis citricola Van der Goot) was also studied. The effectiveness of the treatments was affected mainly by the rate of accumulation of the toxicant in the leaves. At 18 g a.i. per tree, the greatest residues found in the leaves were 106, 12.2 and 1.3 μg 8−1 fresh weight for aldicarb, ethiofencarb and dimethoate, respectively. The concentration in mature leaves was very similar to that in young leaves. The residue levels in the mature fruits were much lower than in the leaves. The main components of the residues in the leaves were aldicarb sulphoxide [2‐methyl‐2‐(methylsulphinyl)‐ propionaldehyde O‐methylcarbamoyloxime], dimethoate, omethoate and ethiofencarb sulphoxide [2‐(ethylsulphinylmethyl)phenyl methylcarbamate]. A laboratory study with synthetic diets showed similar toxicity for all three insecticides, whereas in detached leaves, or when taken up by citrus trees, ethiofencarb was the least toxic to the aphids.
Insecticide resistance in houseflies from the middle east and North Africa with notes on the use of various bioassay techniques
Authors: Taylor Robert N.
Published: November 2006

The susceptibility to pyrethroid, organochlorine, organophosphorus and carbamate insecticides, of 20 strains of houseflies (Musca domestica L.) collected in the Middle East and North Africa, was assessed by topical application. No resistance to pyrethroids was found but most flies were resistant to DDT, gamma‐HCH, organophosphorus and carbamate insecticides. Numerical factors of resistance for a susceptible and two different resistant strains, obtained using different bioassay techniques, were compared. High mortality (≥95%) was achieved with ‘resisted’ insecticides in tests with space sprays, but only low, variable mortality resulted from deposit tests. If this occurs under practical field conditions, moderately resistant populations of flies could be controlled by using space sprays containing comparatively high concentrations of active ingredient, but increased levels of deposit would be ineffective.
The ultrastructure of sporidia of Ustilago avenae after treatment with the fungicides nuarimol and imazalil nitrate
Authors: Hippe Sigrun , Grossmann Friedrich
Published: November 2006

Ultrastructural changes were observed in sporidia of Ustilago avenue (Pers.) Rostr. after treatment with the fungicides nuarimol and imazalil nitrate. Electron microscopic studies of ultrathin sections, as well as of freeze‐fracture replicas, showed that nuarimol caused the following marked changes in the ultrastructure of the cells: increased cell wall thickness and invaginated plasmalemma, with concentrations of extracytoplasmic vesicles in some places between plasmalemma and the cell wall; pores were visible in the septa. Nuarimol‐treated sporidia were characterised by vacuolisation and accumulation of lipid bodies. Compared with nuarimol, imazalil nitrate caused small cytological changes; elongation of the sporidia and enlarged cell diameters, as well as an increased thickness of the septa, were observed, and an enhanced number of mitochondria with reduced diameters were found.
The use of a computerised digitiser for the analysis of spray droplet sizes on oat leaf surfaces
Authors: Nguyen N. Trung , Jarvis Lynn R.
Published: November 2006

The use of fluorescence photomicrography, and a graphic digitiser tablet controlled by a minicomputer, is suggested as the means of rapid and accurate measurement of deposits traced by fluorescence on plant leaves; this method gives the added advantage of a permanent record of the deposits. As an example of the technique, an analysis of 1630 droplets on the upper and lower surfaces of oat leaves, traced with reversibly soluble fluorescent pigments, is described. Measurement on the digitiser, and computer analysis of droplet size data, took less than 20 min.
Synthesis of some 3‐phenyl‐1‐substituted(or 1,1‐ disubstituted)prop‐2‐yn‐1‐ols and their in‐vivo activity against some phytopathogenic fungi
Authors: Arnoldi Anna , Betto Eliseo , Farina Gandolfina , Formigoni Attilio , Galli Remo , Griffini Alberto
Published: November 2006

Thirty‐two 3‐phenyl‐1‐monosubstituted(or 1, 1‐disubstituted)prop‐2‐yn‐1‐ols, mostly with heterocyclic substituents, and four derivatives, were synthesised and tested in vivo against eight fungal plant pathogens of different taxonomic classes. No compound showed a wide spectrum of activity, however, nine of them were effective against Sphaerotheca fuliginea on Cucumis sativus, both in direct protectant tests and in systemic protectant tests by root application.
Comparative fungitoxicity of the insecticide permethrin and ten degradation products
Authors: Stratton Glenn W. , Corke Charles T.
Published: November 2006

The toxic effects of permethrin and ten of its degradation products on the growth of ten fungi were determined. Permethrin was relativelynon‐toxic, with an EC50 of > 100 mg litre−1 but six of the degradation products were significantly (P= 0.05) more inhibitory. The ester hydrolysis products, 3‐phenoxybenzyl alcohol and 3‐(2,2‐dichlorovinyl)‐2,2‐dimethylcyclopropanecarboxylic acid, had EC50 values ranging from 8 to > 100 and 20 to > 50 mg litre−1, respectively. Other degradation products that were more toxic than permethrin included 3‐phenoxybenzaldehyde and 3‐phenoxybenzoic acid, with EC50 values as low as < 1 mg lite−1. Hydroxylated and substituted‐benzene metabolites were non‐toxic. Combinations of selected test compounds yielded both synergistic, antagonistic and additive interaction responses, depending upon the test system employed.
Approaches to relieving aeration stress in waterlogged plants
Authors: Jackson Michael B.
Published: November 2006

A fertile soil contains sufficient water‐filled pores to replenish losses by evapotranspiration and to sustain growth. However, too many such pores can be detrimental because the exchange of gases between the soil, plant roots and the aerial environment is impaired by the water they contain (waterlogging). The consequences include an accumulation of metabolically generated gases (such as ethylene), oxygen deficiency and the production of potentially toxic substances. Knowledge of these effects, and their consequences for growth, hormone production and inorganic nutrient uptake, enhance the prospects for ameliorating flooding injury by prophylactic or restorative means. Theexamples described are (a) the use of more porousmedia for plant containers in the nutrient film technique (NFT) of glasshouse crop production; (b) fungistatic, acid neutralising and oxygen‐releasing seed coatings; (c) boron and nitrogen fertilisation; (d)foliar applications of cytokinins and gibberellins; (e) the inhibition of ethylene action or stimulation of ethylene production in aquatic species.
Electric charge, image‐charge forces, and the deposition of pesticide drops
Authors: McCartney H. Alastair , Woodhead Terence
Published: November 2006

A simulation model has been developed and used to assess the importance of induced image‐charge forces in enhancing the deposition on plant stems and leaves of charged, as compared to uncharged, pesticide drops. The model, through calculations of the dynamics and trajectories of individual drops, allows separate determinations of enhancements of the deposit on the upper and lower leaf surfaces. Trajectories and rates of deposition were computed for water drops having diameters within the range 20 to 100 μm, for charges q between 0.1 and 1.0 times the maximum charge Q that can be retained on a drop of specified radius r, for wind speeds μo of the order of 0.1 to 1 .O ms−1, and for plant stems (represented by vertical cylinders) 2 and 10 mm in diameter, and for plant leaves (horizontal plates) of various along‐wind lengths I. It is shown that the rates of impaction to stems can be described in terms ot two dimensionless parameters that respectively relate to the properties of the particle and of the image force, and the rates of sedimentation to horizontal leaves in terms of the parameters q, r and l/μo. The model predicts that, inside crop canopies, considerable increases in the rates both of impaction and sedimentation can be achieved if drops, particularly small drops, can be given charges close to their respective Q. Thus for drops of 20 μm in diameter, sedimentation under typical within‐canopy conditions is predicted to increase five‐fold as a result of charging the drops, one‐half of the enhanced deposit being on the underside of the leaves. For drops of 40 μ in diameter, predictions for the enhancement of deposition on the uppermost leaves of a field bean crop are shown to agree with published results from a field trial of an electrostatic crop spray system.
Busulphan and thiourea as chemosterilants for the snail lymnaea acuminata
Authors: Singh Ravindra , Agarwal Ram A.
Published: November 2006

Treatment of the snail Lymnaea acuminata with an alkylating agent (busulphan) or a thiocarbamide (thiourea), for 3 days, significantly reduced the number of eggs and prevented embryonic development. Both the drugs caused a dose dependent reduction in the levels of protein, DNA, RNA and the activity of the alkaline phosphatase of the ovotestis, and a dose‐dependent enhancement in the levels of amino‐acids and the activity of the acid phosphatase. Discontinuation of the drug treatment for 7 days resulted in a near complete recovery in DNA and RNA levels, while there was no change in the levels of protein, amino‐acids and the activities of the acid and alkaline phosphatases.
Photodecomposition of chlorothalonil in benzene
Authors: Khan Shahamat U. , Akhtar M. Humayoun
Published: November 2006

Chlorothalonil (2,4,5,6‐tetrachloroisophthalonitrile) in benzene was photodecomposed by sunlight or low energy ultraviolet irradiation to a monophenyl adduct identified as 3,5,6‐trichlorobiphenyl‐2,4‐dicarbonitrile. However, irradiation with a 100‐W high‐energy ultraviolet lamp yielded an additional compound identified as 2′, 5′ ‐dichloro‐m‐terphenyl‐4′, 6′‐dicarbonitrile. Photolysis was followed by a steady decrease in the chlorothalonil and monophenyl adduct concentrations, with a concomitant increase in the diphenyl adduct.
Effects of some foliar fungicides on the chrysomelid beetle Gastrophysa polygoni (L.)
Authors: Vickerman G. Paul , Sotherton Nicholas W.
Published: November 2006

The effects of the fungicides benomyl, thiophanate‐methyl and triadimefon on the chrysomelid beetle Gastrophysa polygoni were investigated in the laboratory. Contact with a suspension of benomyl (1.5 g a. i. litre−1 did not affect the hatchability of the eggs. Larvae were reared on shoots of knotgrass (Polygonum aviculare) that had been sprayed with suspensions of benomyl, ranging in concentration from 0.1 to 5.0 g a. i. litre−1. The mortality to the adult stage, of larvae reared on shoots treated with concentrations of benomyl of 0.5 g a. i. litre−1 and above, was significantly higher than that of control larvae. At concentrations of 2.0 g a. i. litre−1 and above, no larvae survived to the adult stage. The LD50 was 0.78 g a. i. benomyl litre−1. The LT50 values at concentrations of 1.0, 2.0 and 5.0 g a. i. benomyl litre−1 were 22.6, 12.6 and 5.3 days, respectively. The mean weights of adults bred from larvae that had been reared on shoots treated with benomyl (0.5 and 1.0 g a. i. litre−1) were significantly less than those of adults bred from control larvae. The mortality of larvae, reared on shoots of P. aviculare treated with triadimefon (0.5 g a. i. litre−1) or thiophanate‐methyl (1.0 g a. i. litre−1), was also significantly higher than that of control larvae. Females kept on plants of P. aviculare treated with benomyl (1.5 g a. i. litre−1) laid similar numbers of eggs to those kept on untreated plants, and the hatchability of the eggs was not affected.
The effect of the physico‐chemical stability of emulsions of an ester of 2, 4‐D on their biological activity
Authors: Boize Linda M. , Lee Geoffrey W. J. , Tadros Tharwat F.
Published: November 2006

The phytotoxicity of oil‐in‐water emulsions containing the ‘iso‐octyl’ ester of 2, 4‐D [(2, 4‐dichlorophenoxy)acetic acid], prepared by the dilution of emulsifiable concentrates, to Phaseolus vulgaris, was found to be independent of the surfactant concentration (‘Synperonic NPE 1800’ + ‘Ethoduomeen T20’) and of the emulsion stability. Moreover, spray retention was also independent of the surfactant concentration within the range studied (0.01‐150 g litre−1); this could be accounted for in terms of the energetic processes involved during impaction, and the subsequent adhesion of the spray droplets to the target surface. However, the independence of the phytotoxicity of the surfactant concentration and emulsion stability was not expected, and some tentative explanations are given for these results.
Residues of aldicarb in coconut
Authors: Singh Kshatra P. , Pandey Shiv Y. , Khan Mazhar M. , Singh Satendra
Published: November 2006

Determinations were made of aldicarb residues in coconut cultivated on soils containing aldicarb granules. The quantitative estimations in coconut milk and kernel were made by colorimetry and gas‐liquid chromatography; samples harvested at various times were analysed. Residues in samples of kernel did not exceed 0.04 mg kg−1 (total toxic aldicarb residues), while milk samples showed no detectable residues.
Effects of synthetic media on the growth of Neurospora crassa isolates carrying genes for benomyl resistance and vinclozolin resistance
Authors: Grindle Morris
Published: November 2006

A vinclozolin‐resistant mutant (Vin‐1) was derived from a wild type strain of Neurospora crassa by ultraviolet mutagenesis, and the mutant was crossed with a benomyl‐resistant strain (Bml). Progeny carrying the four possiblecombinations of Bml, Bml+, Vin‐1 and Vin‐1+ genes were compared with respect to their radial growth on dishes of synthetic media. The benomyl‐resistant progeny Bml, Vin‐1+ were indistinguishable from the phenotypically normal progeny Bml+, Vin‐1+, and the vinclozolinresistant progeny Bml+, Vin‐1 were indistinguishable from the double mutants Bml, Vin‐1 on most media. Growth and sporulation of isolates carrying the mutant Vin‐1 gene were poor, especially on media of high osmotic pressure and on media enriched with ammonium salts or amino‐acids. Vinclozolin‐resistant isolates were also resistant to chloroneb, dicloran and procymidone. Possible effects of Vin genes on cell wall biogenesis and on the biological fitness of mutants are discussed.