bluuebunny/crossref_metadata_2025 huggingface dataset:
Insecticide resistance patterns among colorado potato beetle, leptinotarsa decemlineata (Say) (Coleoptera: chrysomelidae), populations in north carolina
Authors: French Ned M. , Heim D. Craig , Kennedy George G.
Published: November 2006

A residual bioassay was used to determine insecticide susceptibility in populations of Colarado potato beetle, Leptinotarsa decemlineata (Say), in eastern North Carolina. Mean bioassay mortalities were subjected to correlation analysis to assess patterns of resistance among tested insecticides. Within insecticide classes, cross‐resistance patterns were observed between carbaryl and carbofuran (carbamates), fenvalerate and permethrin (pyrethroids), and among azinphosmethyl, methamidophos, and phosmet (organophosphates). Significant associations between insecticides from different insecticide classes were concluded to be due to multiple resistance. Knowledge of multiple and cross‐resistance patterns are discussed in relation to the bioassay as a tool for monitoring insecticide resistance.
Evidence of synergy between prochloraz and deltamethrin in apis mellifera L.: a convenient biological approach
Authors: Colin Marc‐Edouard , Belzunces Luc P.
Published: November 2006

We have studied the synergistic action of deltamethrin and prochloraz in bees in laboratory experiments that allowed us to express dosages in terms of field rates (g ha−1). It was established that, used alone, deltamethrin at 0·125 g ha−1 and prochloraz at 25 g ha−1 did not produce mortalities different from that of the control during 96 h of observation. Sprayed as a mixture of these doses, deltamethrin and prochloraz produced 67·5% corrected mortality within 24 h and 74·1% corrected mortality within 50 h. Sequential treatments of deltamethrin and prochloraz spaced by a 0·8‐day interval reduced the synergistic action of both molecules. At 50 h, the lethal effects were 27·5% corrected mortality for the treatment of deltamethrin followed by prochloraz and 23·8% corrected mortality for the treatment of prochloraz followed by deltamethrin. Results are discussed in terms of mode of action and sub‐lethal effects.
A mechanistic model to describe organosilicon surfactant promotion of triclopyr uptake
Authors: Buick Rosalind D. , Robson Bruce , Field Roger J.
Published: November 2006

The foliar uptake by field bean (Vicia faba L.) of triclopyrtriethylammonium formulations with and without the organosilicon surfactant “Silwet L‐77” was assessed over 24 h. The Michaelis‐Menten formalism was found to describe the data well and enabled a mechanistic explanation of the effects of L‐77 on triclopyr uptake to be established. L‐77 significantly reduced the time to reach half the maximum uptake of herbicide, k (by 2·8 times), by providing an alternative route via stomatal pores for herbicide entry into the plant. The use of an abscisic acid pretreatment, which artificially closed the stomata, confirmed this route as being the principal contributor to L‐77‐enhanced triclopyrtriethylammonium uptake.
The Use of Artificial Neural Networks in QSAR
Authors: Salt David W. , Yildiz Nihat , Livingstone David J. , Tinsley Chris J.
Published: November 2006

Artificial neural networks (ANN) have their origins in efforts to produce computer models of the information processing that takes place in the brain. They have found application in a wide variety of fields such as image analysis of facial features, traffic management of underground station platforms, hand‐writing verification of cheques, stock market predictions, etc. They have also been applied to computer‐aided molecular design, notably protein structure prediction, and more recently ANN have been used to perform statistical tasks such as discriminant analysis and multiple linear regression in the investigation of Quantitative Structure‐Activity Relationships (QSAR).

We have begun a study of the properties of ANN when used to perform such multivariate statistical analyses. The most popular network used in QSAR‐type applications is the multi‐layer feed‐forward network, also known as the back propagation multi‐layer perceptron (MLP). The approaches of MLP and multiple linear regression to modelling are discussed. In order to give some insight into the operation of MLP networks we have carried out experiments with artificial data. Finally, we report two examples of MLP in computer‐aided design, a QSAR analysis and the prediction of secondary protein structure.
Residue behaviour of fenvalerate, tau‐fluvalinate, lambda‐cyhalothrin and monocrotophos in eggplant (Solanum melongena L.) fruits
Authors: Mukherjee Irani , Gopal Madhuban
Published: November 2006

The persistence patterns of three synthetic pyrethroids—fenvalerate, tau‐fluvalinate, lambda‐cyhalothrin—and an organophosphorus insecticide, monocrotophos, on eggplant (Solanum melongena L.) have been evaluated. The extractable residues ranged from 0.05 to 0.45, 0.01 to 0.40, 0.003 to 0.09 and 0.09 to 0.32 μg g−1 for fenvalerate, tau‐fluvalinate, lambda‐cyhalothrin and monocrotophos, respectively. Fenvalerate was the most persistent among the four, followed by monocrotophos, lambda‐cyhalothrin and tau‐fluvalinate. The Maximum Residue Limit (MRL) of these pesticides on S. melongena has not yet been documented. The present data may be useful for establishing MRL and assessing the amount of pesticide residues in this vegetable.
Synthesis and acaricidal activity of novel fluorinated benzothiazolyl pyrethroids
Authors: Chen Guang‐Ming , Chen Fu‐Heng
Published: November 2006

A series of novel pyrethroids containing a benzothiazole ring which replaces the phenoxy substituent in the benzyl ester portion have been synthesised. The compounds prepared were from four types of acid substituent, and were screened for acaricidal activity against Tetranychus viennenist, Zacher. Several compounds showed good activity at 250 mg litre−1. As expected, it was found that the highest activity was associated with substitution at the 3‐position of the benzyl ring. A fluoro‐or trifluoromethyl‐substituent in the benzothiazole ring usually enhanced potency. α‐Cyano substitution also increased activity.
The interactions between routes of exposure and physicochemical properties of four water‐dilutable permethrin formulations in relation to their activities against Trichoplusia ni (Hubner)
Authors: Thacker J. Richard M. , Hall Franklin R. , Downer Roger A.
Published: November 2006

A series of laboratory experiments were undertaken to compare the activities of four water‐dilutable permethrin formulations against the cabbage looper Trichoplusia ni (Hubner). The formulations used were “Pounce 3.2 EC”, “Ambush 2.0 EC” and two novel formulations (containing evaporation retardants) supplied, for comparison, by Roussel Uclaf Environmental Health Ltd, Berkhamsted, UK (formerly Wellcome Environmental Health Ltd).

Bioassays were developed to investigate the activity of the insecticides via topical, residual and residual/dietary routes of exposure. The test insects were exposed to insecticide droplets, of 200 μm diameter, either directly or indirectly (on cabbage leaves or parafilm) using an on‐demand droplet generator. Following exposure to insecticide, the test species were confined in petri dishes and mortality assessments were made at 24 h after treatment. The results were analyzed using probits.

The results indicated that up to 15‐fold differences in activity between formulations may occur when exposure is via residual contact on an artificial waxy surface (parafilm). The novel formulations were found to be far more active than the standard EC formulations. These differences in activity were significantly correlated with the dynamic surface tension and droplet spread upon cabbage leaves of the formulations.

The results are discussed in terms of the bioavailability of pyrethroids upon waxy surfaces and also in terms of the potential for manipulating the pick‐up of pesticides from plant surfaces.
Development of integrated crop protection in glasshouse ornamentals
Authors: Fransen Joanne J.
Published: November 2006

The production of glasshouse ornamentals in the Netherlands occupies an area of 5278 ha. The total production value is 5·76 billion Dutch guilders. A characteristic of the Dutch ornamental industry is the wide range of products. About 110 species of cut flower and 300 species of pot plant are grown. Reduction of pesticide use can be achieved by the development of alternative and additional methods, like the use of monitoring techniques, natural enemies, host‐plant resistance and closed systems. Information is presented referring to developments in research, extension and practical application of these methods.
Integrated control of diseases in closed systems in the sub‐tropics
Authors: Gullino M. Lodovica
Published: November 2006

The area of land under protected cropping in the sub‐tropical region is surveyed. In the northern part of the region, glasshouses are prevalent, while in the southern part, plastic houses are more common.

Integrated Pest Management (IPM) strategies under the different cultural and climatic conditions are presented, with special emphasis on the use of alternative control measures. The most important soil‐borne and foliar diseases of vegetable and ornamental crops grown in the area are considered with respect to the most effective and widely used control methods.

Use of resistant varieties and appropriate cultural practices is one of the control measures most frequently adopted. Particularly, control of environmental conditions can strongly decrease the severity of some foliar pathogens. In the case of soil‐borne diseases, soil solarization is already carried out in practice. Antagonists, isolated from suppressive soils, can be used successfully against some plant pathogens and, in the future, could provide another option.
Management strategies for controlling pests and diseases in glasshouse crops
Authors: Wardlow Leslie R. , O'Neill Timothy M.
Published: November 2006

Pest and disease control strategy is influenced by (i) the market demand for blemish‐free produce, (ii) the sources of pests and diseases, (iii) the availability of crop cultivars with genetic resistance to pests and diseases, (iv) the presence and availability of beneficial animals in the crop production system, (v) the lack of biological control agents for diseases and (vi) costs of Integrated Pest Management (IPM) and Integrated Disease Control (IDC) programmes. Although only 14000 ha of the potential world area of 75000 ha of protected crops employs IPM, this technique is likely to expand in future, and food and plants produced under IPM regimes will become the norm. During IPM, multiple introductions (MI) of natural enemies can be made regularly at affordable rates, whether pests are seen or not, to ensure that particular pests do not cause crop damage. In this manner, growers are better able to deal with circumstances beyond their control; better use will be made of any effective pesticides, and problems with statutory pest control will be easier to solve.

IDC in protected crops involves skilful manipulation and deployment of factors affecting the outcome of host–pathogen interactions. The most important of these are genetic resistance, control of the aerial and root environments, nursery hygiene, the health status of planting material and appropriate use of fungicides. The precise combination of factors used may vary with crop, time of year, the target spectrum of diseases to be controlled, the economics of alternative actions and between nurseries growing the same crop. Any action should have minimal effects on biological pest control agents. Unlike IPM, where introduction of predators and parasites is a major part of successful pest management strategies, the introduction of micro‐organisms for disease control is often less reliable and, with a few exceptions, rarely practised at present.

Strategies for integrated control of both pests and diseases can be improved by research to increase knowledge on the culture of crops, optimum glasshouse environments, thresholds of pests and diseases and the biology of pests, diseases and their natural enemies. Integration of pesticides with natural enemies has greater potential than is utilised at present and could help to prolong the life of some chemical pesticides.
Integrated pest management at the grower level
Authors: Jensen Egon
Published: November 2006

The development of integrated pest management in greenhouses in Denmark is discussed, together with factors that must be considered if satisfactory control is to be achieved. Current approaches to the control of spider mites, caterpillars, leaf miners, whiteflies, aphids and thrips are recorded.
Physico‐chemical factors determining the phloem translocation of benzoic acids
Authors: Tench Allen J. , Williams Roger H. , Bromilow Richard H. , Chamberlain Keith
Published: November 2006

A series of 14C‐labelled benzoic acids, chosen to permit assessment of the role of pKa and lipophilicity in determining movement in plants of these herbicide analogues, was synthesised and their phloem translocation investigated. Following application of substituted benzoic acids to castor bean, Ricinus communis L., by injection into the petioles, the compounds of intermediate lipophilicity (2‐fluoro‐, 4‐chloro‐ and 3,4‐dichlorobenzoic acids) gave highest concentrations in phloem exudates; 4‐methyl‐2,3,5,6‐tetrafluoro‐ and pentafluorobenzoic acids were less well translocated, perhaps because their pKa values are much less than those of the other benzoic acids studied. The polar 4‐ureidobenzoic acid and the lipophilic 3‐(4‐methylphenoxy)benzoic acid were much less efficiently translocated in phloem. These results are similar to those previously obtained for phenoxyacetic acids, and provide further support for the role of ionisation in the accumulation and retention of chemicals in phloem sieve tubes.
Effects of abamectin on intracellular potassium ion activity and membrane potential in dipteran skeletal muscle
Authors: Fitzgerald Elizabeth M. , Curry Jason , Djamgoz Mustafa B. A.
Published: November 2006

The effects of abamectin (AVMB1) on intracellular potassium ion activity (aKi) and resting membrane potential (Em) of the skeletal muscle cells of final instar larvae of Phormia terraenovae (Diptera) were investigated using K+‐selective micro‐electrodes. Bathing the preparation in 10− M AVMB1(+ 1 ml litre−1 dimethylsulfoxide) for 60 min caused a significant (31%) decrease in aKi, whilst Em depolarized on average by 19 mV (nearly 50% of the original control value). The difference EK‐Em increased by 9 mV, although EK (potassium equilibrium potential) remained more negative than Em. These results could be due to a cationic effect of AVMB1 possibly involving an increase in K+ and Na+ conductances of the muscle plasma membrane.
Determination of residues of endosulfan and endosulfan sulfate on eggplant, mustard and chickpea
Authors: Gopal Madhuban , Mukherjee Irani
Published: November 2006

Extractable residues of endosulfan stereoisomers and its toxic metabolite, endosulfan sulfate, on a vegetable, an oilseed and a pulse crop were determined by gas‐liquid chromatography. The study revealed that the alpha isomer degraded faster than the beta isomer. Beta‐endosulfan accumulated during the first three days following the treatment. Endosulfan sulfate residues appeared a few days after application and decreased with time. The total endosulfan residues in the seeds from treated mustard ranged from 0.08 to 0.12 mg kg−1 and were at or below the limit of determination (0.02 mg kg−1) in chickpea seeds following harvest.
The fungicide captan reduces nuclear DNA content in maize seedlings
Authors: Rayburn A. Lane , Pedersen Wayne L. , McMurphy Lisa M.
Published: November 2006

Captan, a major fungicide used by the US maize industry, was studied to determine its effect on the nuclear DNA content of maize (Zea mays L.) seedlings. Captan was applied to kernels at the recommended agronomic rates. The nuclear DNA content of the seedlings was determined by flow cytometry. In two maize hybrids examined, a reduction in nuclear DNA content was observed. Two different fluorochromes, with different staining mechanisms, were used to determine nuclear DNA content. Both of these fluorochromes revealed a reduction in nuclear DNA. Captan is reported to inhibit DNA synthesis in several animal systems. The reduction of maize nuclear DNA observed in this study may be a result of DNA synthesis inhibition induced by captan.
Correlation of endothal and fluorescent dye concentrations following concurrent application to tidal canals
Authors: Fox Alison M. , Haller William T. , Getsinger Kurt D.
Published: November 2006

Herbicide residue samples are expensive and time‐consuming to collect and analyze. The potential for using ‘Rhodamine WT’ to simulate endothal dissipation in moving water was tested in the weed‐infested Three Sisters tidal canals (Citrus Co., FL). Concurrent applications were made using a variety of application techniques. Significant correlations between dye and endothal concentrations were found in each treatment, indicating that ‘Rhodamine WT’ concentrations can be used to predict endothal movement and concentrations. The ratios of endothal:dye half‐lives were similar (0.2, 0.25, 0.17) for three of the application methods tested, indicating that estimations of dye half‐lives could be used to predict those for endothal.
Investigation of an emulsifiable oil adjuvant and its components on the activity of a new grass herbicide by factorial experimentation
Authors: Grayson B. Terence , Webb James D. , Pack Simon E.
Published: November 2006

The herbicidal activity of a new compound [(±)‐(EZ}‐2‐[1‐allyloxy‐imino)propyr]‐3‐hydroxy‐6‐(4‐cyanophenyl)cyclohex‐2‐ene‐1‐one] (I), selective to broad‐leaf plants, and partially selective in some cereal crops was enhanced by an emulsifiable paraffinic oil (HVI 60E).

In order to determine the amount of HVI 60E to be applied with an emulsifiable concentrate of I (IE) a factorial herbicidal assay involving six concentrations of I and five concentrations of HVI 60E (both sets including zero concentration) was conducted to obtain response surfaces of herbicidal activity. The total selectivity of IE in broad‐leaf species remained for all HVI 60E concentrations. The activity against grass weeds, except Poa annua L., increased markedly with increasing HVI 60E concentration and enhancement of performance of IE by HVI 60E in broad‐leaf crops could be pursued without fear of crop phytotoxicity.

However, the increases in activity against grass weeds were accompanied by increases in phytotoxicity against cereal crops. The response surfaces of Echinochloa crus‐galli(L.) Beauv. and Zea mays L. were coincident and this result terminated further testing in this outlet. However, the response surfaces of Avena fatua L. and Triticum aestivum L. were reasonably well separated. Further tests in this outlet and in broad‐leaf crops are planned around optimum cost‐performance ratios derived from combinations with cost‐response surfaces.

The results of a further lest showed that both components (oil and emulsifier) of HVI 60E were approximately equivalent in adjuvant enhancement activity and so, on cost grounds, a crop oil (low emulsifier content) would be preferred over a crop oil concentrate (high emulsifier content).
Environmental fate of mineral, vegetable and transesterified vegetable oils
Authors: Cornish Alex , Battersby Nigel S. , Watkinson Robert J.
Published: November 2006

Vegetable oils, synthetic esters (including transesterified oils) and mineral oils are the main classes of oil used in pesticide formulations. Biodegradation is a major route for the removal of oils from soil systems. Most of the oils used in pesticide formulations are degraded substantially in the laboratory tests that are used to assess aquatic biodegradability. The susceptibility of different oils to biodegradation can be explained in terms of the metabolic capacity of common microorganisms.

Fewer soil biodegradability tests have been carried out with oils, but the available data suggest that the mode of degradation is not very different from that in aquatic systems. Supplements of inorganic nutrients (in particular nitrogen) are needed to stimulate microbial activity in soils containing the high concentrations of oil that can be encountered in the event of a spill. However, oils are applied at such low rates in pesticide form illations (maximum of 5g oil m− soil) that nutrient availability is unlikely to affect the rate of biodegradation in the field.
The plasma membrane as a barrier to herbicide penetration and site for adjuvant action
Authors: Wade Brian R. , Riechers Dean E. , Liebla Rex A. , Wax Loyd M.
Published: November 2006

Adjuvants are traditionally thought to exert their main effect on the cuticle or spray droplet to enhance foliar‐applied herbicide penetration. However, considerable evidence exists indicating that the plasma membrane is a barrier to intracellular penetration of herbicides and a site of action for adjuvants. Surfactants may penetrate through the cuticle and into the region of the plasma membrane. Insertion into the membrane causes a general “ loosening” to provide greater penetration by highly polar herbicides such as glyphosate. Weak acid herbicides typically have a lipophilic moiety and, therefore, can move more easily through the membrane but the rate and accumulation is dependent on pH conditions across the membrane. Ammonium salts have been shown to affect the pH of the apoplast in a manner which allows faster penetration and greater accumulation of weak acid herbicides. Examination and understanding of the plasma membrane as a barrier to herbicide penetration will aid in defining the mechanisms of adjuvant action and improve the efficiency of agrochemical use.
Fungicidal activity of a series of chloroacetylanilidophosphonates
Authors: Ha Hyun‐Joon
Published: November 2006

Nine diethyl chloroacetylanilidomethylphosphonates and ten diethyl α‐(chloroacetylanilido)benzylphosphonates were prepared by N‐chloroacetylation of the corresponding diethyl anilinomethyl‐ and anilinobenzylphosphonates. These were tested for antifungal activity against six phytopathogenic fungi. Most of the compounds showed moderate protective properties. No significant difference in activity was observed for compounds with an extra aryl ring substituent on the methylene group of the backbone. Compounds with electron‐withdrawing substituents, especially chlorine, on the aniline site (R1) showed higher fungicidal activity than the other compounds with electron‐donating groups as substituents.
Effects of wind direction, wind speed and travel speed on spray deposition
Authors: Nordbo Ebbe , Kristensen Kristian , Kirknel Erik
Published: November 2006

Deposition variability from a conventional field sprayer, and effects of wind and travel speed were measured by collecting on small artificial targets in the swath. Whilst deposition on 0.1‐m2 plots varied by a factor of 3, deposition on single vertical targets typically varied by a factor of 10 and on horizontal targets by a factor of 6. Distinct transversal deposition patterns appeared according to wind direction. The quantity and structure of variability was compared with wind speed and turbulence intensity, but few significant trends were found. Deposition on vertical targets was enhanced by increasing wind speed or increasing travel speed, whilst effects on horizontal targets were inconsistent.
HPLC determination of fenoxaprop and fenoxaprop‐ethyl in different soils
Authors: Celi Luisella , Négre Michéle , Gennari Mara
Published: November 2006

This paper describes a method for the determination of fenoxaprop ethyl and fenoxaprop residues in four soil types using two extraction procedures: extraction with 0.1 M hydrochloric acid/methanol, partitioning with dichloromethane and extraction with ethyl acetate. The extracts were purified on florisil or alumina cartridge. The analyses were performed by reverse phase HPLC with UV detection at 280 nm.

The best results in terms of recovery, clean‐up efficiency and independence of soil characteristics were obtained with the combination ethyl acetate extraction alumina clean‐up. Under these conditions, the recoveries were higher than 70 % and the detection limit was 0.02 mg kg−1 soil.
Influence of diammonium sulfate and other salts on glyphosate phytotoxicity
Authors: Nalewaja John D. , Matysiak Robert
Published: November 2006

Diammonium sulfate is commonly used as an adjuvant with glyphosate, but reports vary regarding its effect on weed control, and its possible function in enhancing glyphosate phytotoxicity is not fully understood. Several experiments were conducted in the glasshouse to determine glyphosate phytotoxicity to various species as influenced by diammonium sulfate in distilled water and in the presence of antagonistic salts. Diammonium sulfate overcame sodium hydrogen carbonate, calcium chloride, and 2,4‐D antagonism of glyphosate phytotoxicity to wheat (Triticum aestivum L.). Sulfate anions were important for overcoming calcium antagonism, possibly by forming calcium sulfate. Scanning electron micrographs of spray droplets of glyphosate with calcium chloride and diammonium sulfate indicated the presence of crystals, presumed to be calcium sulfate, that were independent of the glyphosate deposit. Diammonium sulfate may also provide ammonium ions to form effective glyphosate‐ammonia complexes rather than less effective calcium, sodium, diethylamine, or other cation complexes. Diammonium sulfate also may influence susceptibility to glyphosate by affecting herbicide absorption into foliage of certain species. Glyphosate phytotoxicity to sunflower (Helianthus annuus L.) was increased whereas phytotoxicity to kochia [Kochia scoparia (L.) Schrad.] and soybean [Glycine max (L.) Merr.] was reduced by diammonium sulfate applied in the absence of antagonistic salts; diammonium sulfate apparently has several functions as an adjuvant with glyphosate.
Organosilicone surfactants as adjuvants for agrochemicals
Authors: Stevens Peter J. G.
Published: November 2006

The literature has been reviewed and 160 references are presented to provide an overview of organosilicones as adjuvants for agrochemicals. Early studies (1973–1981) elucidated the special properties of these compounds, notably their extreme spreading and, by virtue of the exceptionally low surface tensions of their aqueous solutions, the ability to induce infiltration of spray formulations into foliage via stomata. Subsequent research at the New Zealand Forest Research Institute explored these and other properties in‐depth, and demonstrated that they enabled the herbicide glyphosate to be used as a cost‐effective alternative to 2,4,5‐T for the control of forest scrubweeds. As a result, in 1985, ‚Silwet’︁ L‐77 was the first organosilicone adjuvant to be commercialised, and various other products have subsequently been introduced. The chemistry and synthesis of these organosilicones have been detailed. A mechanistic approach has been adopted to consider the effects of the distinctive properties of organosilicones in each of the processes involved in spray application of agrochemicals. Commencing with spray formulation, the topics of foaming, hydrolytic stability and interactions with coformulants are discussed. Progressing to spray application, consideration is given to the effects of organosilicones on atomisation and impaction (wetting, adhesion/reflection, spreading, retention/run‐off), and the resultant influences on the activity of protectant agrochemicals. An assessment of the use of organosilicones with systemic agrochemicals includes examination of effects on foliar uptake, via both cuticular and stomatal pathways, and the rainfastness which the latter provides. Also considered is the physiological behaviour of organosilicones, specifically phytotoxicity and effects on translocation of active ingredients. The current and potential future use of organosilicones with herbicides, foliar nutrients, growth regulators, insecticides and fungicides is discussed, as is the specificity of their effects. Additionally, the potential application of organosilicone chemistry to adjuvant classes other than the spreader/penetrant type investigated to date is considered. Finally, the issues of registration, handling hazards, both toxicological and chemical, and environmental impact are discussed. The literature reviewed demonstrates the sound science base on which this novel class of organosilicone adjuvant chemistry rests.
The influence of a fatty amine surfactant on foliar absorption and translocation of the trolamine salt and iso‐octyl ester of 2,4‐D
Authors: de Ruiter Hans , Straatman Kees , Meinen Esther
Published: November 2006

The influence of the surfactant ‚Armoblen’︁ 600 (tallow amine block polymer containing a block of polymerized propylene oxide groups (12PO) and a block of polymerized ethylene oxide groups (5EO)) on the foliar absorption and translocation of 2,4‐dichlorophenoxyacetic acid trolamine salt (2,4‐D TR) and 2,4‐dichlorophenoxyacetic acid iso‐octyl ester (2,4‐D IOE) was investigated. Absorption and translocation were monitored for 48 h after application. During this period, without surfactant the leaves of black nightshade (Solanum nigrum L.) absorbed 2.4 times more 2,4‐D IOE than 2,4‐D TR whereas pea leaves (Pisum sativum L.) absorbed 1.3 times more 2,4‐D IOE than 2,4‐D TR. Pea leaves absorbed more of both compounds than did those of black nightshade. Addition of surfactant (5 g litre−1) enhanced the absorption of 2,4‐D TR by black nightshade (4.8‐fold after 48 h) and pea (1.7‐fold after 48 h) but reduced the absorption of 2,4‐D IOE. Without surfactant the absorption of 2,4‐D TR and 2,4‐D IOE was not affected by drying of the drops. Addition of surfactant enhanced absorption of 2,4‐D TR after the drops had dried. Translocation of 2,4‐D TR in black nightshade and in pea, expressed as percentage of the amount absorbed, was reduced by the presence of surfactant. At the end of the observation period this reduction was no longer observed. The translocation efficiency of 14C from 2,4‐D IOE was not influenced by the surfactant. The effects of the surfactant are discussed in relation to its possible mode of action.
Effects of monodisperse alcohol ethoxylates on mobility of 2,4‐D in isolated plant cuticles
Authors: Schönherr Jörg
Published: November 2006

Effects of monodisperse ethoxylated n‐alcohols on the mobility of 2,4‐dichlorophenoxyacetic acid (2,4‐D) in cuticular membranes isolated from pear (Pyrus communis L.) and bitter orange (Citrus aurantium L.) leaves, and from green pepper (Capsicum annuum L.) and tomato (Lycopersicon esculentum L.) fruits were measured. The surfactants were of the type C1Ej, where i is the number of carbon atoms of the alcohol, j is the number of ethylene oxide groups and i = 2j. Surfactant effects on mobility increased with time and were inversely proportional to the mobility of 2,4‐D in cuticles prior to surfactant treatment. C4E2 was barely effective. C6E3, C8E4 and C10E5 were the most effective surfactants, as they increased the mobility of 2,4‐D by 15‐ to 20‐fold and the effects were established very rapidly. As the molecular weights of the surfactants increased, their effects decreased and the time‐dependence of effects became more pronounced. Response (susceptibility) of cuticles to surfactant treatment varied among plant species and increased in the order bitter orange < tomato < pear < pepper. Surfactant effects did not correlate with HLB or with cuticle‐water partition coefficients of surfactants tested. It is argued that penetration of surfactants into cuticles is a prerequisite for increasing 2,4‐D mobility and that effects should be proportional to the surfactant concentration in the cuticles. Since rates of foliar penetration are proportional to solute mobilities in cuticles it is expected that the surfactants that were most effective in this study would be suitable accelerator adjuvants for systemic pesticides.
Antagonism of the foliar uptake of glyphosate into grasses by organosilicone surfactants. Part 1: Effects of plant species, formulation, concentrations and timing of application
Authors: Gaskin Robyn E. , Stevens Peter J. G.
Published: November 2006

Radiolabelled glyphosate was used to investigate the antagonistic effects of an organosilicone surfactant, ‚Silwet’︁® L‐77™, on the foliar uptake of the formulated herbicide into four grass species, over a 24‐h time‐course. While the effect of L‐77 addition was generally to increase the initial rate of uptake of glyphosate, thereafter the rate was slowed or even halted, such that an overall decrease in uptake was evident as early as 4 h after application in one of the species tested. Further extensive studies on wheat investigated L‐77 effects on uptake of the herbicide as both the pure mono‐isopropylammonium salt, and as the formulated product containing a tallow amine polyethoxylate surfactant. The addition of L‐77 initially increased, but after 1 h reduced the rate of glyphosate uptake, regardless of formulation. There was no evidence that antagonism resulted from any surfactant interaction between the organosilicone adjuvant and the tallow amine co‐formulant. Antagonism was directly related to the concentration of L‐77, and inversely related to that of the formulated herbicide and of its tallow amine co‐formulant. Applied prior to glyphosate application, L‐77 reduced the amount of herbicide in the foliage, and failed to increase substantially the initial rate of uptake. When applied after the a.i., instant enhancement of glyphosate uptake took place with some stomatal infiltration observed, but thereafter no significant cuticular penetration occurred. The mechanisms by which L‐77 could interfere with the cuticular penetration of glyphosate are discussed in light of these results.
Effect of organosilicone‐based adjuvants on herbicide efficacy
Authors: Singh Megh , Mack Robert E.
Published: November 2006

Laboratory and field experiments were conducted to evaluate the efficacy of the post‐emergence herbicides, fluazifop‐P‐butyl, glyphosate‐isopropyl‐ammonium, paraquat, and glyphosate‐trimesium (sulfosate) as influenced by organosilicone‐based adjuvants, ‚Dyne‐Amic’︁ and ‚Kinetic’︁. Conventional adjuvants ‚Agri‐Dex’︁ and ‚Induce’︁ were included in all experiments for comparison. The experimental plots were naturally infested with bahiagrass, camphorweed, common lambsquarters, Florida pusley, Jerusalem oak, hairy beggarticks, pigweed, and teaweed. Herbicides were applied alone or in combination with ‚Dyne‐Amic’︁, ‚Kinetic’︁, ‚Agri‐dex’︁, or ‚Induce’︁ using a tractor‐mounted boom sprayer. ‚Dyne‐Amic’︁ (2.5 ml liter−1) was as effective as ‚Agri‐dex (10 ml liter−1) in increasing the efficacy of herbicides on grass and broadleaf weeds studied. ‚Kinetic’︁ at 2.5 ml liter−1 was as effective as ‚Induce’︁ at 2.5 ml liter−1 in increasing the efficacy of herbicides on the weeds studied. Paraquat tank‐mixtures with the pre‐emergence herbicides bromacil and diuron were more effective when applied at a spray volume of 280 liter ha−1 than at 140 liter ha−1. Fluazifop‐P‐butyl and glyphosate‐isopropylammonium were more effective at 186 than at 93 liter ha−1. Addition of ‚Kinetic’︁ or ‚Induce’︁ to the herbicide spray solution had no effect on pH, but fluazifop‐P‐butyl reduced pH to 5.1 or increased it to 7.7 when added to the 93 and 186 liter ha−1 preparations, respectively. Glyphosate‐isopropylammonium reduced pH to 5.0 at the lower, but had little effect on pH at the higher rate. Reduction in static surface tension and contact angle was greater with organosilicone‐based adjuvants than with conventional adjuvants.
Feeding behavior of Plutella xylostella and Leptinotarsa decemlineata on leaves treated with Bacillus thuringiensis and esfenvalerate
Authors: Hoy Casey W. , Hall Franklin R.
Published: November 2006

Studies were conducted to examine interactions between esfenvalerate and Bacillus thuringiensis Berl. in their effects on feeding behavior of larvae of Plutella xylostella L. and Leptinotarsa decemlineata Say. Droplets containing esfenvalerate, B. thuringiensis, the two in combination, and water controls were individually applied to leaf disks. Third‐instar P. xylostella larvae were allowed to feed for 24 h on cabbage disks and third‐instar L. decemlineata larvae were allowed to feed for approximately 18 h on potato leaf disks. For each insect species and each treatment, the proportion of leaf area removed during the feeding period was regressed on the proportion of droplets removed during that period to test for avoidance of droplet residues. No significant differences were found between treatments in these regressions for L. decemlineata. In contrast, B. thuringiensis, either alone or in combination with esfenvalerate, significantly affected the relationship of leaf and droplet consumption for P. xylostella. No evidence of individual droplet avoidance, i.e. a consistently greater proportion of leaf than droplets consumed, was found for any of the treatments. Proportions of leaf consumed and proportions of droplets consumed were compared among treatments to test for effects on feeding rate. B. thuringiensis significantly reduced feeding rate, both alone and in combination with esfenvalerate for P. xylostella and alone for L. decemlineata. We found no statistically significant differences in feeding rate due to esfenvalerate. The species studied can be expected to consume the same amount of B. thuringiensis whether it is mixed with esfenvalerate or not, whereas esfenvalerate dose by ingestion would be reduced if it were mixed with B. thuringiensis.
A study of the possible interconversion of hexachlorocyclohexane stereoisomers on chickpea
Authors: Gopal Madhuban , Mukherjee Irani
Published: November 2006

A field trial was conducted to study (i) whether there is interconversion of stereoisomers of hexachlorocyclohexane (HCH) on a plant and (ii) the rate of dissipation of lindane on chickpea in a sub‐tropical climate. The lack of formation of the beta and delta isomers on application of pure alpha‐ or gamma‐HCH showed that these stereoisomers of HCH did not interconvert on chickpea. The residues of the alpha and gamma isomers dissipated rapidly on chickpea leaves with half‐lives of three and four days respectively.
A comparative study of carbofuran metabolism in treated and untreated soils
Authors: Talebi Khalil , Walker Colin H.
Published: November 2006

Soils which have been pretreated with carbofuran can degrade the insecticide more rapidly than untreated soils, with a consequent loss of efficacy. In laboratory studies, soils pretreated with carbofuran were found to degrade the chemical more rapidly than soils which were not so pretreated. When pretreated soils were sterilised, the rate of carbofuran degradation was much reduced, indicating that most of it was due to microbial action. Incubation of pretreated soil with [phenyl‐U‐14C]carbofuran led to the rapid disappearance of the parent compound (3 % left after seven days). Most of the 14C was accounted for as bound residue after seven days, whilst smaller amounts were recovered as carbon dioxide, 3‐hydroxycarbofuran, 3‐ketocarbofuran, and an unknown metabolite. Incubation of pretreated soil with [carbonyl‐14C]carbofuran led to rapid loss of the parent compound and the recovery of 73% of 14C as carbon dioxide by five days.

Most of the bound 14C (>90%) arising from [phenyl‐U‐14C]carbofuran treatment of pretreated soil was extracted by 1 M sodium hydroxide and about half of the extracted 14C was precipitated with ‘humic acids’ after acidification. These and other results suggest that the major metabolic route for carbofuran in pretreated soils involves hydrolysis of the ester bond leading to (1) release of carbofuran phenol which rapidly binds to soil organic matter and, (2) release of the carbonyl moiety which quickly degrades to generate carbon dioxide.
Control of Spodoptera spp. using ULV formulations of the acylurea insect growth regulator, flufenoxuron: Field studies with Spodoptera exempta and effect of toxicant concentration on contact activity
Authors: Fisk Tanya , Cooper Jerry , Wright Denis J.
Published: November 2006

Field trials in Kenya showed that an ultra‐low‐volume (ULV) application of flufenoxuron (25 g a.i. litre−1; 1–0 litre ha−1) gave consistently good control of late‐instar larvae (L4‐L6) of the armyworm, Spodoptera exempta Walk. Flufenoxuron gave equivalent or greater control of S. exempta than did cypermethrin (24 g a.i. litre−1; 1–0 litre ha−1) from 96 h after ULV application. While initial (24–48 h) levels of larval mortality were greater with cypermethrin, many larvae treated with flufenoxuron showed signs of incomplete moulting after 48–72 h and would have been unable to feed normally. Laboratory spray bioassays with L3 Spodoptera littoralis suggested that the ULV formulation of flufenoxuron was most active at 25 g a.i. litre−1 when compared with higher (50 g) or lower (6.25 and 12.5 g a.i. litre−1) rates. Topical application studies with ULV formulations containing [14C]flufenoxuron showed that the accumulation of pesticide by L3 S. exempta over 1–4 h was consistently greater in larvae treated with 25 g than with 12.5 g flufenoxuron litre−1 and while initially lower, accumulation of pesticide appeared to be greater in larvae treated with 25 g than with 50 g flufenoxuron litre−1 after 2–4 h. The potential of ULV formulations of flufenoxuron for control of S. exempta is discussed.
Concurrent events in the uptake by insects of cypermethrin from a microemulsion formulation
Authors: Lankford William , Dawson Bernard
Published: November 2006

Changes in formulation composition at the site of in‐vivo applications of an oil‐in‐water cypermethrin microemulsion have been determined on American cockroaches (Periplaneta americana). Surface washes of 0.6‐μl deposits on femur cuticle recovered decreasing amounts of radio‐labelled diluent water, toluene and cypermethrin with time. After 30 min, only cypermethrin (22.5 % w/w initial dose) could be removed in significant amounts. Extraction of cuticle underlying the site of application indicated similar but independent, patterns of initially increasing levels followed by a decline from the maximum, for all three compounds.

Recoveries of formulants in the surface washes were utilised to describe the post‐application nature of the microemulsion deposit as provided by the formulation phase diagram. The initial and most rapid movement of cypermethrin away from the surface deposit apparently took place via the intact oil‐in‐water microemulsion. Some 6 min after application, the deposit entered a viscoelastic gel phase with no further phase change indicated.
Natural products as a source of agrochemicals and leads for chemical synthesis
Authors: Pillmoor John B. , Wright Kenneth , Terry Adrian S.
Published: November 2006

The use of natural products as a source of new agrochemicals and the procedures that can be undertaken to discover such compounds are reviewed using examples from both the literature and our own experiences. The commercial successes obtained to date show that natural products are a powerful source of new agrochemicals. The results from a survey of the views of the agrochemical industry of natural product work indicated a high level of interest, with 16 of the 19 companies that replied being involved in natural product work either through in‐house or external programmes of work. Possible approaches to the key challenges of atural product work, for example choice of sources and screens, avoiding known metabolites and obtaining sufficient compound for biological evaluation, are discussed.
Plant products to control plant parasitic nematodes
Authors: Birch A. Nicholas E. , Robertson Walter M. , Fellows Linda E.
Published: November 2006

Plants produce a wide range of defensive compounds (allomones) to protect themselves from predators and pathogens. Selected allomones have been screened against plant parasitic nematodes for a range of activities such as anti‐hatching, repellent, nematotoxic, anti‐feedant or anti‐viurs vectoring activities and inhibition of female development. Plant‐growth stimulation and anti‐nematode activities complementary to host‐plant resistance were also studied. Examples are presented of ways in which plant‐derived compounds can interfere with the life cycles of nematodes and their close relationships with host plants. The potential of plant‐derived compounds in future environmentally benign integrated pest management of nematodes is discussed.
Algae as a source of biologically active products
Authors: Cannell Richard J. P.
Published: November 2006

Algae are a large and diverse group of organisms from which a wide range of secondary metabolites have been isolated. A number of these compounds possess biological activity such as toxicity, antibacterial, antifungal, antiviral, antitumour and other specific activities. An indication of the range and diversity of algal metabolites and their biological activities is given and the potential of algae as a source of useful biologically active products is discussed.
Investigation of relative rates of solvent and solute penetration through protective glove materials
Authors: Watkinson Adam C. , Brain Keith R. , Walters Kenneth A. , Hadgraft Jonathan
Published: November 2006

Pesticides are often formulated as a concentrate in volatile organic solvents. The most important means of preventing the contamination of workers using the concentrate is by the use of protective clothing, particularly gloves. The influence of formulation solvent on solute permeation rates across selected protective glove materials has been investigated. In one of the cases studied, the solute penetrated the glove material appreciably faster than the formulation solvent. This result, therefore, questions the manner in which gloves are often selected for protection against pesticide formulations (by selecting the glove that offers the best protection against the formulation solvent rather than the active ingredient). Although this is a preliminary study, it is recommended that, to gain the maximum protective effect, all selected gloves are tested using the formulation of choice and that the permeation of all components of the formulation is monitored and reported. It may, therefore, be necessary for glove and pesticide manufacturers to re‐examine the way in which these tests are carried out and the processes of product selection used.
Chemical precursors for studying the effects of glucosinolate catabolites on diseases and pests of oilseed rape (Brassica napus) or related plants
Authors: Dawson Glenn W. , Doughty Kevin J. , Hick Alastair J. , Pickett John A. , Pye Barry J. , Smart Lesley E. , Wadhams Lester J.
Published: November 2006

A range of 3, 5‐disubstituted 1,3, 5‐thiadiazinane‐2‐thiones are described which decompose in moist air to give organic isothiocyanates. Organic isothiocyanates are the main biologically active catabolites from the glucosinolate components of crucifers. The thiadiazinanethiones provide a source of organic isothiocyanates for biological studies and examples of tests with pathogens and insect pests of oilseed rape are given.