bluuebunny/crossref_metadata_2025 huggingface dataset:
The toxicity of benomyl and some related 2‐substituted benzimidazoles to the earthworm Lumbricus terrestris
Authors: Stringer Austin , Wright Michael A.
Published: November 2006

Benzimidazole and its 2‐amino analogue were non‐toxic to Lumbricus terrestris when administered orally. The fungicidal 2‐substituted benzimidazoles (benomyl, carben‐dazim, fuberidazole and thiabendazole) and l‐(benzimidazol‐2‐yl)‐3‐butylurea were highly and equally toxic. The equitoxicity of compounds with widely differing substituent groups suggests a common mode of action—the benzimidazole moiety being the active part of the molecule. It is likely that there is a common mode of action for benzimidazole analogues for both fungicidal activity and earthworm toxicity. There was no detectable effect on the cholinesterase levels of earthworms poisoned by benomyl. But it is confirmed that the cholinesterase inhibitory activity of benomyl in vitro is due to formation of butyl isocyanate.
Pyridyl terpenoid ethers with high juvenile hormone activity
Authors: Solli Hauk , Madsen Hans Berg , Hoist Preben L. , Klemmensen Per D.
Published: November 2006

Pyridyl terpenoid ethers have outstanding juvenile hormone activity in Tenebrio molitor compared with their phenyl analogues (6,7‐epoxy‐3,7‐dimethyloct‐2‐enyl 6‐ethyl‐3‐pyridyl ether and 7‐ethoxy‐3,7‐dimethyloct‐2‐enyl 6‐ethyl‐3‐pyridyl ether are active at 100 pg/larva). The compounds were also active in Galteria mellonella and Culex pipiens.
Determination of bromide ion content of cereals and other foodstuffs by specific ion electrode
Authors: Banks H. Johnathon , Desmarchelier James M. , Elek Jane A.
Published: November 2006

A method is presented which determines the bromide ion content of foodstuffs using a bromide specific ion electrode. For low levels of bromide (< 10 mg/kg) or for accurate work, bromide was extracted from the ground commodity with water and then separated from interfering compounds by ion‐exchange chromatography before estimation. Alternatively, bromide ion can be estimated approximately by direct measurement on the aqueous extracts after heating to denature proteins. The method was checked against three standard methods of bromide estimation in foods, using wheat that had been repeatedly fumigated with methyl bromide. The equipment required is inexpensive and can be adapted for field use. The method has been used to determine the bromide and chloride contents that occur naturally in wheat, maize, copra, soya beans and sorghum.
Transformations of 4‐chloro‐o‐toluidine in soil: Generation of coupling products by one‐electron oxidation
Authors: Iwan Jorg , Hoyer Georg‐A. , Rosenberg Douwe , Goller Dieter
Published: November 2006

Four coupling products formed by one‐electron oxidation of 4‐chloro‐o‐toluidine were isolated from soil samples after 90 days of incubation with [14C]chlordimeform (200 mg/kg). The metabolic compounds were identified as 4,4′‐dichloro‐2,2′‐dimethyl‐azobenzene, 4‐chloro‐6‐nitro‐o‐toluidine, N‐(4‐chloro‐o‐tolyl)‐2‐methyl‐p‐benzoquin‐one monoimine and 2‐(4‐chloro‐o‐toluidino)‐N‐(4‐chloro‐o‐tolyl)‐6‐methyl‐p‐benzo‐quinone monoimine, respectively. Mechanisms of formation and possible significance of these substances as indicators for metabolic pathways to mineralisation of aniline derivatives are discussed. The chlordimeform soil concentrations (70–100 mg/kg) necessary for the formation of the azobenzene and the benzoquinone monoimines are at least 10 times higher than those occurring after actual field application.
Sex pheromones for the control of lepidopterous pests using microencapsulation and dispenser techniques
Authors: Campion Derek G.
Published: November 2006

Sex pheromones may be used for the control of insect pests by causing communication disruption for long enough to decrease mating and therefore diminish subsequent larval infestations. Such an approach presents the problem of maintaining the pheromone concentration at a high enough level in the field for weeks or even months. To overcome this difficulty two systems are at present generally employed; the establishment of a relatively small number of large pheromone sources in suitable dispensers at fixed points in the treatment areas, or using a very large number of small sources by microencapsulating the pheromone which can then be applied directly to the crop by conventional methods. Recent field experiments carried out using both these methods are described, and problems and future prospects discussed.
Experience with pheromone trapping and disruption of moths
Authors: Minks Albert K.
Published: November 2006

Maxima in the population of the summerfruit tortrix moth, Adoxophyes orana, have been detected in orchards in the Netherlands using traps containing its pheromones. Attempts to disrupt the pheromone communication of A. orana in orchards using geometrical isomers of the pheromone have given variable results. Factors, in particular temperature, affecting pheromone communication in A. orana are discussed.
Factors favouring the choice of flamprop‐methyl, methyl (±)‐2‐[N‐(3‐chloro‐4‐fluorophenyl)benzamido] propionate for the control of avena species in wheat
Authors: Jeffcoat Brian , Norton Harries W. , Thomas David B.
Published: November 2006

The post‐emergence herbicide, methyl (±)‐2‐[N‐(3‐chloro‐4‐fluorophenyl)benzamido]‐propionate, flamprop‐methyl, showed good activity against oat with selectivity in wheat. It was superior in performance to flamprop‐isopropyl and benzoylprop‐ethyl already being marketed for wild oat control. It gave even more effective control of seed set in the oat than did the other compounds, prevented tiller growth and as a result of its higher activity was less dependent on crop competition. Selectivity of flamprop‐methyl, however, was similar to that previously reported for related compounds, i.e. it was dependent on its rate of degradation and the subsequent detoxication of the biologically active acid to inactive conjugates. The rate of degradation of flamprop‐methyl is comparable to that of benzoylprop‐ethyl but the more active acid produced accounts for the improved performance of the former. The corresponding ethyl ester showed the highest rate of degradation and although generally comparable in performance to the methyl ester there was a tendency for the inhibition on the oat to last for a shorter period. Performance of flamprop‐methyl is influenced by environmental factors such as temperature or water stress. These factors had an effect during the first 2 weeks after compound application, reducing the translocation of the active metabolite to its site of action and having a small but detectable effect on the amount of acid produced.
Seasonal Fluctuations in the Concentration of BHC Residues in Butter
Authors: Harper David B. , McAnally Robert J.
Published: November 2006

Marked seasonal changes in the BHC content of butter in Northern Ireland are reported. Levels of alpha‐BHC rise to a maximum of between 0.5 and 0.9 mg/kg on a fat basis in January and February, falling to between 0.02 and 0.04 mg/kg in late summer and early autumn. The use of veterinary preparations containing technical BHC for the control of lice infection in the winter months would appear to be responsible for such fluctuations. Maximum BHC contamination of milk in January and February probably arises by direct ingestion or skin absorption of externally applied BHC and subsequent transfer from the bloodstream to the milk fat. A later smaller contamination peak in the April/May period is probably due to mobilisation of BHC stored in the body fat of the animals during the first weeks after parturition.
The metabolism of mebenil in rats, rabbits and guinea‐pigs
Authors: Warrander Alan , Waring Rosemary H.
Published: November 2006

The metabolism of mebenil (o‐toluanilide) was studied in rats, rabbits and guinea‐pigs. The major metabolite in all three species was 4′‐hydroxy‐o‐toluanilide, both free and as glucuronide and sulphate conjugates. Traces of aniline were also excreted, showing that the amide bond was hydrolysed in vivo.
Pesticide residues: Food surveys in the United Kingdom
Authors: Egan Harold , Weston Ralph E.
Published: November 2006

The development of food surveys for levels of pesticide residues, toxic metals and polychlorobiphenyls and related compounds is outlined. The role of the surveys in monitoring the effect on the levels of compounds in specific foods following changes in pesticide usage is explained. Studies over 8 years on levels in the total diet show they are well below the acceptable daily intakes recommended by the Food and Agriculture Organisation/World Health Organisation for organchlorine and other pesticides. During this period the levels found have in general declined.
Plant growth regulators and the physiological limitations to yield in sugar beet
Authors: Lenton John R. , Milford George F. J.
Published: November 2006

Improvements in seed germination, the early establishment of leaf cover, storage root development and the control of bolting would all increase the yield of sugar beet in the UK. Plant growth at these stages of development is controlled by genotype and by climatic factors acting through endogenous growth substances and is potentially capable of modification by applied growth regulators. For example, sugar beet responds to changes in daylength and spectral quality of light at the end of the day by increasing lamina and petiole growth, light interception and plant growth rate. Changes in endogenous gibberellins in young leaves of plants growing in different photoperiods and the responses of these leaves to applied gibberellic acid are presented as evidence for the involvement of gibberellins in leaf expansion in sugar beet.
The new nrdc pyrethroids as agricultural insecticides
Authors: Ruscoe C. N. E.
Published: November 2006

The extremely high insecticidal activity and favourable toxicology of the synthetic pyrethroids are properties which have always made them attractive insecticides. However, their marked instability, coupled with a relatively high cost of manufacture, has always precluded their widespread use in agriculture. The new synthetic pyrethroids, typified by permethrin (NRDC 143), thus represent a significant advance in agricultural insecticide terms, since they show greatly increased stability while retaining the favourable properties of high insect and low mammalian toxicity. A considerable amount of knowledge has been obtained from laboratory and field experiments with the new pyrethroids over the last two years. This paper surveys the results obtained, which have confirmed the high level of efficacy of this series of compounds against some of the most important pests of agriculture.
Problems faced by the pesticide manufacturer in relation to social and economic aspects of crop protection
Authors: Marmet Jurg P.
Published: November 2006

The following questions are discussed: Is the research‐based part of the chemical crop protection industry still a business proposition? If it is not, why should it stay in this business any longer? If it is, what will its future be?
Social and economic aspects of alternative insect control methods
Authors: Lindquist D. A.
Published: November 2006

The development of alternative pest control methods offer a number of advantages over the conventional methods of pest control, under certain circumstances. These advantages will be discussed in the light of current social and economic pressures. In addition, the method of developing these alternative methods of pest control will be discussed in relation to the development of conventional methods of pest control. The so‐called area‐wide insect control schemes will be compared with farmer applied methods of insect control in relation to industry, training and economics.
Designing laboratory screens for biologically active chemicals in the pharmaceutical industry
Authors: Ferguson Robert A.
Published: November 2006

The design of laboratory tests to screen large numbers of chemicals, in the hope of finding a few which are biologically active, presents special problems of optimisation. These may be studied using mathematical formulations or, less formally, by the examination of operating characteristic curves. Screening strategies which use two or more stages are often very efficient.
Methods of testing rodenticides in the field against rats
Authors: Rennison Brian D.
Published: November 2006

Poisons used in bait to control rats are of two kinds; single‐dose acute poisons and those with a slow or cumulative action lethal only if two or more daily doses are consumed. The two types require different baiting techniques and different methods must be used for testing them in the field. For acute poisons, the relative sizes of rat infestations have to be measured by baiting with unpoisoned bait both before and after poison baiting and the pre‐treatment sizes taken into account when analysing the results. When testing possible cumulative or multiple‐dose poisons, pre‐treatment baiting is unnecessary and the method used was that originally devised for field testing for anticoagulant resistance in rats. Examples of published results of field trials of both types of poison are discussed.
Fumigation of tobacco in polyethylene lined cases with methyl bromide
Authors: Hill Terence W.
Published: November 2006

Experimental fumigations of cased tobacco with methyl bromide to control the Cigarette beetle (Lasioderma serricorne) were conducted at low temperatures. Two stowages, each of 120 × 181 kg cases, were built and made gas‐tight with seamless polyethylene film. Methyl bromide was introduced into each stowage at a concentration of 64 g/m3. Gas concentrations were monitored at a depth of 15 cm into the tobacco and at the centre of cases. Six cases (two open, two with folded polyethelene liners and two with heat‐sealed polyethylene liners) were sampled in each stowage. Good penetration was achieved when atmospheric temperatures ranged from 6.5 to 8.5°. It is concluded, therefore, that tobacco fumigations with methyl bromide may be carried out satisfactorily in cold weather, providing that temperatures do not fall to a level at which insects become highly tolerant to the fumigant. However, amounts of fumigant reaching the centre of the heat‐sealed cases were insufficient to ensure the effectiveness of such treatments in all situations. It is recommended, therefore, that the procedure of slitting polyethylene liners of heat‐sealed cases before fumigation be continued.
The action of allethrin on the peripheral nervous system of the frog
Authors: Van Den Bercken Joep
Published: November 2006

A study was made of the neurotoxic effects of the pyrethroid insecticide allethrin on the peripheral nervous system of the frog by means of electrophysiological techniques. The principal action of allethrin is to induce repetitive activity, not only in sensory nerve fibres and in sense organs, but also in the distal part of the motor fibres, leading to pronounced repetition in the motor end‐plate. Measured by the number of repetitive nerve impulses allethrin shows a marked negative temperature coefficient of activity in the lateral‐line sense organ and in the motor nerve terminal.
Some effects of cismethrin on the rabbit nervous system
Authors: Carlton Margaret
Published: November 2006

The effects of cismethrin, 5‐benzyl‐3‐furylmethyl (1 R)‐cis‐chrysanthemate, in the spinal rabbit have been investigated at the level of the sensory receptors, in an afferent nerve, and in the spinal cord. Cismethrin causes a lowering of the threshold of some sensory receptors and the appearance of spontaneous activity, which may be in bursts, in some afferent fibres that were previously silent. When recordings were made from the afferent nerve, in addition to phenomena arising from the effects on sensory receptors, there was repetitive firing in the nerve when action potentials were evoked by electrical stimulation. The effects on the spinal cord were such as to increase the excitability of reflex arcs. There was also a change in the normal pattern of facilitation and inhibition as measured by the amplitude of the second of two suitably spaced monosynaptic responses and it is suggested that this is an indirect effect of cismethrin intoxication. The cumulative effect of the changes brought about in nervous activity in the system described here could account at least in part for the convulsions observed in intoxicated animals.
Factors governing the toxicity of putative synaptic transmitters and their analogues when injected into the haemocoel of adult male Lucilia sericata
Authors: Hart Richard J. , Potter Charles , Wilson Roger G.
Published: November 2006

Acetylocholine, arecoline, 2‐(dimethylamino)ethyl acetate, L‐glutamic acid, L‐4‐methyl‐eneglutamic acid, (±)‐quisqualic acid, 4‐aminobutyric acid, and dicrotophos were injected into the haemocoel of adult male Lucilia sericata. Large doses of the putative transmitters and their analogues were required for toxicity. The water soluble organo‐phosphate dicrotophos was much more toxic than any of the other compounds. Electrophysiological experiments indicated that the putative transmitters were reaching their presumed site of action in the nervous system and that their toxicity could be correlated with the intensity and duration of their effect at this site. Biochemical measurements of the rate of loss of the putative transmitters from the haemolymph indicate that, in vivo, the test insect possesses efficient mechanisms for removing these compounds from the system being studied. It is concluded that the low toxicity of the putative transmitters, which are presumed to interact reversibly with post synaptic receptor sites, may be largely due to their rapid removal from the system, resulting in a rapid fall in concentration at the receptor site.
The synthesis of potential insecticides designed to bind to the acetylcholine receptor
Authors: Baillie Alister C. , Corbett John R. , Sharpe Trevor M.
Published: November 2006

A variety of compounds designed to bind to the acetylcholine receptor, a largely unexploited target for new insecticides, have been prepared. These are related to either the isothiocyanates prepared previously in our laboratory, which probably bind to the receptor, or to nereistoxin, which is known to do so. Many of the compounds are insecticidal, and electro‐physiological studies on a candidate compound, N,N‐dimethyl‐3‐thiocyanato‐2‐(thiocyanatomethyl)propionamide, suggest they may have the predicted mode of action.
Comparison of solvent systems for extracting herbicide residues from weathered field soils
Authors: Smith Allan E.
Published: November 2006

The extraction from several field soils of the four herbicides benzoylprop‐ethyl, nitrofen, profluralin, and tri‐allate applied at least 6 months previously was compared using six solvent systems. The residues extracted were quantified using gas chromatographic techniques. Similar recoveries were achieved using 30% aqueous acetonitrile or acetonitrile + water + glacial acetic acid mixtures. The presence of the acetic acid was found to increase residues extracted only in the case of tri‐allate. Methanol and 10% aqueous acetonitrile were slightly less efficient in recovering residues from the weathered field soils whereas acetone tended to be a poor solvent for the extraction of the chemicals studied.
Loss of fenitrothion on grains in storage
Authors: Desmarchelier James M.
Published: November 2006

Loss of fenitrothion from post‐harvest application to wheat, oats, paddy rice and sorghum followed a second‐order rate process, with rate of loss being proportional, at a fixed temperature, to the amount of fenitrothion and the activity of water, which was obtained from the equilibrium partial pressure of water vapour. The effect of temperature on loss was of the form of the Arrhenius equation. A chart relating half‐life to temperature and relative humidity is presented in a form suitable for field use, and a mechanism is proposed for loss of fenitrothion.
Toxicity of calciferol, warfarin and their combinations to Rattus norvegicus (albino) and R. rattus
Authors: Bai K. Muktha , Krishnakumari Mandyam K. , Majumder Suvendu K.
Published: November 2006

The response of Rattus norvegicus and R. rattus to calciferol, warfarin and a combination of these compounds was tested. Both species succumbed to the recommended bait concentrations of calciferol (1000 mg/kg) and warfarin (250 mg/kg) when tested individually. However, R. rattus was more susceptible to lower concentrations of calciferol (500 and 750 mg/kg) as compared to R. norvegicus, which was sensitive to lower concentrations of warfarin (12.5 and 25 mg/kg bait). Addition of calciferol at different concentrations did not affect the toxicity of warfarin against R. norvegicus. However, with R. rattus calciferol (250–350 mg/kg) or warfarin (50 mg/kg bait), which individually produced partial mortality, in combination produced a complete kill besides accelerating death. Combination of higher dosages of calciferol with warfarin (1000 + 250 mg/kg bait) tested against both species showed no advantages, resulting in neither lower bait consumption nor speedier death, though individually the components gave complete kills.
The pyrethrins and related compounds. Part XXII. Preparation of isomeric cyano‐substituted 3‐phenoxybenzyl esters
Authors: Elliott Michael , Janes Norman F. , Pulman David A. , Soderlund David M.
Published: November 2006

Preparation of 3‐phenoxybenzyl chrysanthemates and their dihalovinyl analogues substituted with a cyano group at the 2‐, 6‐, (R)‐α‐, or (S)‐α‐ positions is described. The (R)‐ and (S)‐ isomers of α‐cyano‐3‐phenoxybenzyl esters of 2,2‐difluoro‐, ‐dichloro‐, and ‐dibromo‐vinyl analogues of cis‐ and trans‐ chrysanthemic acid are separated chromatographically, as are the separate pairs of enantiomers of fenvalerate, (RS)‐α‐ cyano‐3‐phenoxybenzyl (RS)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate. An optically active ester of α‐cyano‐3‐phenoxybenzyl alcohol (obtained using D‐oxynitrilase) with 2,2,3,3‐tetramethylcyclopropanecarboxylic acid is synthesised.
Phosphinate inhibition studies of cholinesterases
Authors: Horton Gary L. , Lieske Claire N. , Lowe John R.
Published: November 2006

The kinetic constants, Kd, k2, and ki, were determined for the inhibition by 4‐nitro‐phenyl methyl(phenyl)phosphinate of three cholinesterases: butyrylcholinesterase, bovine erythrocyte acetylcholinesterase and eel acetylcholinesterase. Stopped‐flow kinetic evaluations and automated data acquisition and processing were employed. A broad range in affinity for the phosphinate inhibitor was observed as reflected by the binding constants, Kd. A similar wide range in the k2 values for the unimolecular inhibition step was obtained. The net bimolecular rate constants, ki, indicate equal overall reactivity for butyrylcholinesterase and eel acetylcholinesterase with a smaller inhibition rate constant for bovine erythrocyte acetylcholinesterase.
Movement and distribution of ethylene in plants in relation to the regulation of growth and development
Authors: Jerie Peter H. , Zeroni Moshe , Hall Michael A.
Published: November 2006

Work is described showing that ethylene does not move about the plant in physiologically significant amounts due to resistance in the longitudinal direction and loss by emanation from the surface of the plant. Nevertheless, changes in ethylene concentration in one part of the plant may influence concentrations in other parts. It is shown that the partition coefficients for ethylene between air and various plant organs are relatively high and may change in the course of development. These results are discussed in relation to compartmentation of ethylene within the plant and the possible implications of such compartmentation for the control of plant growth and development.
Lipid changes in plants at temperatures inducing chill‐hardiness
Authors: Wilson John M.
Published: November 2006

Phase transitions in the membrane lipids of chill‐sensitive plants at 12°C and below are considered to result in an increase in the activation energy of membrane‐bound enzymes and membrane permeability, leading to cell death. In agreement with this hypothesis, chill‐hardening at 12°C results in an increase in the degree of unsaturation of the fatty acids associated with the membrane phospholipids of Phaseolus vulgaris and Gossypium hirsutum leaves. However, drought‐hardening P. vulgaris leaves at 25°C is as effective in preventing chilling injury as chill‐hardening at 12°C but drought‐hardening produces no increase in the degree of unsaturation of the membrane fatty acids suggesting that lipid phase changes are not the primary cause of chilling injury. Furthermore, a re‐examination of the conditions under which water and electrolytes leak from P. vulgaris leaves indicates that phase changes in the membrane lipids of the plasmalemma and other organelles at 5°C are only of minor importance in determining the extent and speed of chilling injury. The primary cause of chilling injury to P. vulgaris leaves on transfer from 25°C, 85%r.h. to 5°C, 85%r.h. is leaf dehydration due to the opening of the stomata at a time when the permeability of the roots to water is low. The primary factor inducing hardening against chilling injury in P. vulgaris is a water stress and not low temperature per se. Phase transitions in the membrane lipids of a chill‐resistant species have now been detected within the same temperature range as those reported for chill‐sensitive species. Therefore, the ability of temperate species to withstand chilling injury cannot be explained solely on the maintenance of a high degree of unsaturation of the membrane fatty acids.
The antifungal activity of polyoxin B and iprodione against phytopathogenic fungi recently isolated from diseased plants in Japan
Authors: Sakurai Hisashi , Fujita Shoko
Published: November 2006

A comparison was made of the minimum inhibitory concentrations (MICs) of polyoxin B and iprodione against Alternaria mali, A. kikuchiana and Botrytis spp. isolalated from diseased plants from various regions of Japan. Several of these fungal isolates differ markedly in their sensitivity to iprodione and polyoxin B. A study was made of the relationship between the MIC values of polyoxin B and iprodione against several isolates and disease control obtained when these materials were applied to plants infected with the same isolates.
The usage of pesticides on vegetables grown as part of an arable farm rotation
Authors: Sly John M. A.
Published: November 2006

The usage of pesticides on vegetable crops grown mostly on arable holdings in Norfolk in 1972 is reviewed. During the spring of 1973, visits were made to about 300 holdings which grew vegetables for human consumption in 1972. Of these, 74 holdings were in Norfolk. An analysis has been made of the cropping on the holdings in Norfolk and it was shown that vegetables were usually grown as part of an arable rotation rather than as a mainly horticultural enterprise. The usage of pesticides to control pests, diseases and weeds has been examined for the more important vegetable crops together with the reasons for usage and methods of application. A comparison is made between the usage in 1972 and that of 1969.
The computation of concentration–time products for fumigations
Authors: Chanter Dennis O.
Published: November 2006

A recently published method for computing ct products is based on an equation which is dimensionally inconsistent. The errors involved in using such an equation are pointed out, and an alternative method, based on a rectangular hyperbola, is presented. The alternative method is not subject to dimensional inconsistencies and the computation is easier.
Residues of diuron and phytotoxic degradation products in aquatic situations. I. Analytical methods for soil and water
Authors: Bowmer Kathleen H. , Adeney John A.
Published: November 2006

Thin‐layer and gas‐liquid chromatography, ultraviolet analysis and bioassay with Chlorella spp. have been used to investigate the pathway of degradation of diuron to phytotoxic derivatives when diuron was used as a soil‐residual herbicide in irrigation canals. Observations suggest that 1‐(3,4‐dichlorophenyl)‐3‐methylurea and 1‐(3,4‐dichlorophenyl)urea make a contribution to total residues equivalent to a maximum of about 40 and 55%, respectively, of diuron concentrations. Application of a phyto‐toxicity rating suggests that in this environment, measurement of diuron specifically would underestimate the total phytotoxicity of residues by a maximum of about 7%.
Studies on poly(acrylic acid) induced resistance to viral and non‐viral plant pathogens
Authors: Cassells Alan C. , Flynn Theresa
Published: November 2006

Studies on polymer size, concentration and mode of application, either as foliar spray or soil drench, in relation to the induction of resistance to tobacco mosaic virus (TMV) in Nicotiana tabacum cv xanthi‐nc by poly(acrylic acid) (PA) are reported. PA also induced resistance to TMV in N. glutinosa, to pelargonium leaf curl virus in Datura stramonium, to cucumber mosaic virus in Vigna sinensis and to tobacco ring‐spot virus in N. tabacum cv White Burley. No TMV was detected in PA‐treated tomato cv Virocross 11 days after inoculation; but the susceptible cultivar Craigella became infected. PA treatment had no effect on TMV replication in White Burley tobacco but resistance was induced to Peronospora tabacina, a fungal pathogen of N. tabacum cv xanthi‐nc. The potential of PA‐induced resistance as a control measure for viruses and fungi is discussed.
Controlling pests of tropical legumes; current recommendations and future strategies
Authors: Gerard Brian M.
Published: November 2006

Legumes have evolved effective defences against many pests by accumulating high levels of poisonous or indigestible compounds, pubescence and vigorous growth. These defences are greatly reduced in many cultivars of cowpea and common bean, which are susceptible to a succession of pest complexes. Stem pests and defoliators may kill seedlings but well‐established plants tolerate heavy insect damage to leaves, flowers and green pods before pod or grain yields are reduced; virus vectors and root‐knot nematode may be of greater importance. Generally, pod‐borers, pod‐sucking bugs and seed beetles are the main key pests. Control programmes are based on post‐flowering treatments with broad spectrum insecticides. Battery‐powered, controlled‐droplet application machines are ousting knapsack sprayers in small‐scale farming and competing with tractors and aircraft in larger units; subsistence cropping is still predominant and most legume crops remain unsprayed. Consequently, current emphasis is placed on developing cultivars with high yield potential and multiple pest and disease resistance. Insect infestations are lower in most other major legume crops largely due to pubescence (e.g. soybean, blackgram, greengram), fruiting in the dry season (e.g. pigeonpea, chickpea) or geocarpy (e.g. groundnut). Future entomological research will presumably concentrate on assessing the status of pests on resistant cultivars and introducing integrated control methods for the key pests.
Pesticide usage on bananas with special references to fungicides
Authors: Waller James
Published: November 2006

Bananas (including plantains) are widely grown throughout the tropics both for local consumption and for export. Pesticide usage is confined largely to the export crop because of its value and the susceptibility to diseases of varieties suitable for the export market. Most of the bananas grown for export are produced in Latin America and the Caribbean. Weed control with herbicides is particularly valuable in young banana plantations before a mature canopy is produced and when weeds compete with the shallow rooting system. Insecticides are used to control high populations of the banana weevil and may be used against fruit thrips. Nematicides are used extensively to control the banana root nematode and granular applications are now replacing soil injections. Fungicidal control of Sigatoka leaf diseases and fruit diseases has been practised for many years and is essential for the production of high quality, exportgrade fruit. Changes in the chemicals used and in application techniques have brought important benefits in recent years and genetic resistance is likely to play a large part in disease control in the future.
Permethrin as a residual insecticide against cockroaches
Authors: Carter Stuart W. , Chadwick Peter R.
Published: November 2006

The pyrethroid permethrin was shown to be active against Blattella germanica, Periplaneta americana and Blatta orientalis. In laboratory tests on plywood panels the best formulation was a 25% wettable powder which showed an initial LC50 of 10 mg m−2 against B. germanica and lost activity at the weekly rate of 1.9 mg m−2. An initial deposit of 108 mg m−2 gave 50% kill after one year. The synergist piperonyl butoxide diminished residual performance. In one field trial, good control was maintained for more than four months with an initial deposit of 50 mg m−2, the smallest dose used. From this and other trials, the recommended rate of application for general use in long‐term control is 100 mg m−2. A distinctive slow expellent action against B. germanica was seen in field trials.
Degradation of the herbicide flamprop‐isopropyl in soil under laboratory conditions
Authors: Hitchings Eric J. , Roberts Terry R.
Published: November 2006

The degradation of the wild‐oat herbicide flamprop‐isopropyl, [isopropyl (±)‐N‐benzoyl‐N‐(3‐chloro‐4‐fluorophenyl)alaninate], in four soils has been examined under laboratory conditions with sampling times of up to 45 weeks after treatment. The major degradation product of [14C]flamprop‐isopropyl in all soils at up to 10 weeks after treatment was the carboxylic acid (±)‐N‐benzoyl‐N‐(3‐chloro‐4‐fluorophenyl)alanine. This compound in turn underwent degradation by loss of the benzoyl group and the propionic acid moiety, with evolution of [14C]carbon dioxide to form 3‐chloro‐4‐fluoroaniline (CFA). The CFA was formed slowly in soil and occurred mainly as a bound form. There was evidence to show that the CFA was subsequently converted into other polar products. The time for depletion of 50% of the applied herbicide was approximately 10 weeks in sandy loam and medium loam soils, 11 weeks in a clay loam soil and 23 weeks in a peat soil.
Direct observation of the distribution of radiolabelled ethirimol in soil by resin impregnation and autoradiography
Authors: Collier Graham F. , Graham‐Bryce Ian J. , Knight Brian A. G. , Coutts John
Published: November 2006

A procedure for examining the distribution of ethirimol in soil is described. Soil samples containing ethirimol are initially freeze‐dried at −5 to −10°C, impregnated with Araldite resin and hardeners under vacuum and then maintained for 16 h at room temperature followed by 24 h at 100°C, to complete curing. The impregnated soils may then be sectioned and the radiolabelled pesticide located by autoradiography. The distribution of ethirimol within the soil was found to be unaffected by either freeze‐drying or impregnation. The method enables the distribution to be determined on a small scale directly in undisturbed soil sections from both the laboratory and the field. It was used to investigate the effects of soil type on the movement of ethirimol. Structural and textural factors appear to have an important influence on the redistribution of this fungicide and may override the effects of adsorption.
Effect of pH on the degradation of atrazine, dichlorprop, linuron and propyzamide in soil
Authors: Hance Raymond J.
Published: November 2006

The rates of disappearance of atrazine, dichlorprop, linuron and propyzamide were measured in two soils incubated at 22°C and 80% water holding capacity. Observations were made at four pH levels in each soil. Atrazine degradation was relatively insensitive to pH; it increased slightly with increasing pH in one soil and decreased in the other. The other compounds all degraded more slowly at low pH in both soils although dichlorprop had essentially disappeared in 14 days under all conditions, so that the effect of pH is not unlikely to be of practical interest. The ratios of the degradation rates of atrazine, linuron, and propyzamide varied with the soil and the pH.
Action of pesticides on earthworms. Part II: Elimination of parathion by the earthworm Eisenia foetida (Savigny)
Authors: Stenersen Jørgen
Published: November 2006

The earthworm, Eisenia foetida, eliminated parathion and carbofuran at first order rates when continually rinsed in water after treatment with the pesticides. This experiment was also carried out on Lumbricus rubellus for comparison. Carbofuran which is more soluble in water, was eliminated quicker than parathion. The later rate of elimination was very similar for the two species, but immediately after injection the rate was much higher in E. foetida. The metabolism of 1‐ethyl14C labelled parathion and paraoxon (diethyl 4‐nitrophenyl phosphate) was studied in E. foetida. The worm was able to convert parathion to paraoxon by a rather slow process although this metabolite could not be detected in the worms due to its rapid transformation to diethyl hydrogen phosphate. Indirectly, paraoxon can be postulated as a parathion metabolite because of a progressive depression of cholinesterase level observed after treatment with parathion. Small amounts of diethyl hydrogen phosphate were detected as a metabolite of parathion; this is also an indication of paraoxon formation. During the 30 h following injection of parathion, only 4.4% of the applied dose was recovered as water‐soluble metabolites (2.8% in the worms and 1.6% in the sand surrounding them), while 52% was recovered as unmetabolised parathion. Because of inefficient injection, only 70‐59% of the dose thought to be injected was recovered. Therefore the part of the actual applied dose that remained unmetabolised was probably even greater (88%). Five days after injection of parathion, 15 and 9.3 % of the recovered radioactivity in the surrounding sand and in the worm extracts, respectively, was identified as O,O‐diethyl O‐hydrogen phosphorothioate, 3.7 and 7.0% as diethyl hydrogen phosphate, 8.8 and 3.3% as O‐ethyl O‐4‐nitrophenyl O‐hydrogen phosphorothioate (desethylparathion) and/or O‐4‐aminophenyl O,O‐diethyl phosphorothioate, while 70.3 and 80.4% was unmetabolised parathion. Paraoxon was very quickly hydrolysed to diethyl hydrogen phosphate in vivo and in vitro. The in‐vitro hydrolysis was associated with a microsomal fraction and was not inhibited by ethylenediaminetetra‐acetic acid or 4‐(chloromercuri)benzoic acid, and incompletely by aldicarb. Cholinesterase and arylesterase were therefore excluded as enzymes responsible for the activity.
Action of pesticides on earthworms. Part III: Inhibition and reactivation of cholinesterases in Eisenia foetida (Savigny) after treatment with cholinesterase‐inhibiting insecticides
Authors: Stenersen Jørgen
Published: November 2006

The degree of inhibition and the rate of recovery of total cholinesterase level were investigated after in‐vivo treatment of the earthworm Eisenia foetida (Savigny) with aldicarb, carbaryl, carbofuran, oxamyl, and the O‐analogues of bromophos (bromo‐phosoxon), parathion (paraoxon), parathion‐methyl (paraoxon‐methyl), and trichloronate (trichloronatoxon). The results can be explained by the presence of two cholinesterases (E1 and E2), which were demonstrated by in‐vitro inhibition studies. E1 was the most sensitive to all the inhibitors tested. The in‐vivo reactivation rate after inhibition with paraoxon was very high for E1 and very low for E2. Therefore, pretreatment with paraoxon probably increased the toxicity of carbaryl. It was concluded that the toxicity towards E. foetida can be explained in terms of cholinesterase inhibition, provided that the action on the two cholinesterases and the worms' tolerance for a transient but almost total cholinesterase depression are taken into account. Data are given showing that two other species of earthworms also contain different types of cholinesterases with respect to reactions with inhibitors.
Sites of action of photosynthetic inhibitor herbicides; Experiments with trypsinated chloroplasts
Authors: Pallett Kenneth E. , Dodge Alan D.
Published: November 2006

The effect of four photosynthetic inhibitor herbicides, bromacil, ioxynil, metribuzin and monuron, on chloroplast electron transport was investigated. All four compounds completely inhibited electron flow with tripotassium hexacyanoferrate as oxidant, but the inhibition caused by bromacil, metribuzin and monuron was almost totally reversed by trypsin treatment. With ioxynil, only a partial degree of reversability was shown. With a molybdosilicate as oxidant, electron transport was not completely inhibited by any of the herbicides. Whereas the partial inhibition was reversed by tryptic digestion in the presence of bromacil, metribuzin and monuron, there was virtually no reversal in the presence of ioxynil. The results suggest a common site of action for all four herbicides and an additional site for ioxynil nearer to photosystem II.
Synthesis, spectral properties and insecticidal, acaricidal and ovicidal activities of some O‐(1,5‐disubstituted‐ 6‐oxo‐12H‐pyridazin‐4‐yl) phosphorothioates
Authors: Konec̆ný Václav , Kovác̆ Štefan , Varkonda Štefan , Šustek Ján
Published: November 2006

A synthesis of O,O‐dialkyl, O‐alkyl O‐2‐chloroethyl (or O‐2‐ethoxyethyl) O‐(1,5‐disubstituted‐6‐oxo‐1H‐pyridazin‐4‐yl) phosphorothioates is described. Infrared, Raman and ultraviolet spectra of the compounds prepared are interpreted. The wave‐numbers of the v(CC) bands were correlated with substituent constants. Good linear correlations of v(CO) with σ, σF, σI and σR were observed for compounds containing various substituents in the neighbourhood of the keto group of the pyridazinone ring. The insecticidal, acaricidal and ovicidal activities of O‐(ethyl or isopropyl), O‐(alkyl, 2‐chloroethyl, or 2‐ethoxyethyl) O‐(5‐methoxy‐1‐methyl‐6‐oxo‐1H‐ pyridazin‐4‐yl) phosphorothioates, O‐ethyl O‐isopropyl O‐(5‐methoxy‐1‐substituted‐6‐oxo‐1H‐pyridazin‐4‐yl) phosphorothioates and O‐ethyl O‐isopropyl O‐(1‐methyl‐5‐substitutedd‐oxo‐1H‐pyridazin‐4‐yl) phosphorothioates are reported together with the toxicity of some of these compounds to rats.
Use of the scanning electron microscope and cathodoluminescence in studying the application of pesticides to plants
Authors: Hart Clifford A.
Published: November 2006

The efficacy of a pesticidal formulation is in part affected by the surface to which it is applied. During the drying process, spray drops can interact with the complex microenvironment of trichomes, secretory glands, stomata, epicuticular wax and cuticle of the leaf epidermis. The subsequent uptake and persistence of the deposit can be further influenced by the action of the microclimate, including humidity, temperature, rain and dew. The scanning electron microscope (SEM), which is an instrument ideally suited for the study of the surface of bulk specimens, has been used to show the spreading and distribution of pesticides applied as sprays and individual drops to leaf surfaces. Particle size, crystal growth and co‐precipitation of the active ingredient with surfactants and other adjuvants have also been investigated. The SEM can also show how some pesticides and their adjuvants continue to be taken up by the leaf long after the drops have visibly dried. Phytotoxicity, sometimes associated with the penetration of active ingredient or formulation adjuvant, can also be demonstrated using the microscope, especially if either specifically emits cathodoluminescence. These images can also supply complementary information concerning the persistence of deposits, provided that interpretation of the results is carried out with care and, if possible, in conjunction with residue and biological assays.
Microscopy and image analysis in the study of plant pathogens and the application of pesticides
Authors: Jones Philip
Published: November 2006

Problems associated with the preparation of diseased plant material for transmission electron microscopy (TEM) and the uses of TEM to meet the specific needs of plant virologists are discussed. Methods of collecting spray droplets for analysis by an image‐analysing computer method are described.
Mechanisms of DDT resistance in larvae of the mosquito Aedes aegypti L
Authors: McDonald Alan E. , Wood Roger J.
Published: November 2006

Larvae of eight strains of Aedes aegypti were exposed to DDT and compared for resistance, DDT uptake, in‐vivo breakdown of DDT and residual unmetabolised DDT. Resistance varied widely between strains, three being fully susceptible, two almost immune and three of intermediate resistance. Breakdown of DDT by dehydrochlorination to 1,1‐dichloro‐2,2‐bis(4‐chlorophenyl)ethylene (pp'‐DDE) occurred in all strains and was greater in the five resistant types, but there was no significant correlation between the extent of breakdown in the resistant strains and the level of resistance. Moreover the overall difference between susceptible and resistant strains disappeared when they were compared at a low, almost sublethal, concentration of DDT. Larvae of resistant strains carried a greater absolute quantity of unmetabolised DDT in the body and were able to tolerate levels of DDT that were lethal to susceptible larvae. However the two most resistant strains (T8 and B51) contained significantly less DDT plus pp'‐DDE than strains of intermediate resistance (T30 and BSJ) from which they had been derived. Addition of the synergist chlorfenethol to DDT increased its knockdown effect on all resistant strains, suggesting that dehydrochlorination was a factor in resistance. Three strains, two DDT‐resistant and one DDT‐susceptible, were tested with 1,1‐bis(4‐ethoxyphenyl)‐2,2‐dimethylpropane (I), an insecticide that cannot be dehydrochlorinated. All the strains were relatively tolerant to it although the DDT‐susceptible strains were less tolerant. Addition of the synergist sesamex decreased the level of tolerance to I in all strains which suggested that microsomal oxidation made some contribution to it. It is concluded that three factors contribute to larval DDT resistance in A. aegypti; (a) increased metabolism to pp'‐DDE; (b) increased tolerance to unmetabolised internal DDT; and (c) reduced content of DDT+pp'‐DDE (only in the most resistant strains and due either to reduced absorption or increased excretion). These factors are discussed in relation to known larval resistance genes RDDT1 and y.
The structural rearrangement of iprodione in ethanolic solution
Authors: Cooke Barry K. , Loeffler R. S. Thomas , Pappas Athanasios C.
Published: November 2006

Iprodione, in ethanolic solution, was found to undergo structural rearrangement over a period of days to give a solid product which was shown by mass spectrometry to be an isomer. Mechanistic considerations led to a proposed structure, which was verified by synthesis of an authentic specimen by an unambiguous route. The biological implications of these findings are discussed.
Measurement of petroleum oil deposits on citrus leaves by gas‐liquid chromatography
Authors: Furness Geoffrey O. , Howard Rex T. , Smith Peter J.
Published: November 2006

The quantity of oil deposited on citrus leaves when sprayed with oil‐in‐water emulsions was determined by gas‐liquid chromatography of a diethyl ether extract of the leaves. Recovery of oil diminished rapidly as the time interval between spraying and extraction increased; this effect must be recognised when the method is applied.
The extraction and assay of thiabendazole in strongly adsorbing soils
Authors: Cayley George R. , Lord K. Alan
Published: November 2006

Thiabendazole is strongly adsorbed on soils, and is not readily extracted by conventional solvents. two‐phase solvent system consisting of a mixture of aqueous ammonium chloride solution (pH 10), ethanol and chloroform was developed which extracted thiabendazole from a range of soils including high‐organic fen peat soils and mushroom compost. Subsequent partition of the extract between organic solvents and acid or alkaline solutions provided sufficient clean‐up for assay by ultraviolet or fluorescence spectroscopy, of concentrations of less than 1 mg thiabendazole kg−1 of soil. Investigation of the adsorption of thiabendazole from aqueous solution by soils indicated the importance of both soil organic and mineral matter and the adsorption of both neutral and protonated molecules.