bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance to inhibitors of sterol biosynthesis in field isolates or laboratory strains of the eyespot pathogen Pseudocercosporella herpotrichoides
Authors: Leroux Pierre , Gredt Michel , Boeda Philippe
Published: November 2006

Strains of Pseudocercosporella herpotrichoides collected in France on winter wheat give either fast‐growing mycelial colonies with regular margins or slow‐growing mycelial colonies with irregular margins. Most of the fastgrowing isolates were sensitive to triadimenol (EC50 below 2mg litre−1), but some of them were resistant to this inhibitor of sterol C‐14 demethylation. In contrast, all the slow‐growing strains were highly resistant to triadimenol (EC50 greater than 100 mg litre−1). This resistance was also expressed in inhibition of germ‐tube elongation. Positive cross‐resistance was observed between most of the inhibitors of sterol C‐14 demethylation, with the exception of some imidazole derivatives (clotrimazole, prochloraz). All the fast‐growing strains were tolerant to fenpropimorph and fenpropidin whereas the slow‐growing ones were susceptible; the reverse was true with piperalin and tridemorph. All the field isolates were inhibited to the same extent by the inhibitors of squalene‐epoxidase, nafifine and terbinafine.

Two types of mutant resistant to triadimenol have been induced under laboratory conditions from sensitive fast‐growing strains. The most common mutants were resistant to all the inhibitors of sterol C–14 demethylation and also in some conditions to fenpropimorph, tridemorph and the inhibitors of squalene‐epoxidase. The other mutants were characterised by a reduced spectrum of cross‐resistance between triadimenol and the other inhibitors of sterol biosynthesis.

The field isolates and laboratory mutants resistant to triadimenol and propiconazole were also resistant to each of the four enantiomers of these two fungicides.
Residues of diflubenzuron and two of its metabolites in a forest ecosystem after control of the pine looper moth, Bupalus piniarius L
Authors: Mutanen Ritva M. , Siltanen Hilkka T. , Kuukka V. Pekka , Annila Erkki A. , Varama Martti M. O.
Published: November 2006

Diflubenzuron, 1‐(4‐chlorophenyl)‐3‐(2,6‐difluorobenzoyl)urea was used to control the pine looper population in about 1160 ha of Scots pine stand in eastern Finland in summer 1984. The control measure was effective, resulting in the collapse of the population in the treated area. Residues of diflubenzuron and two of its metabolites, 4‐chloroaniline and 4‐chlorophenylurea, were determined in water, pine needles, litter, humus, boleti and other wild mushrooms, bilberry (Vaccinium myrtillus L.) and cowberry (Vaccinium vitis‐idaea L.) samples taken from this area. In water samples taken from the treated area diflubenzuron was still detected at concentrations of 0.1 μg litre−1 2 months after application. No diflubenzuron was detected in this area the following year, nor outside the treated area. Neither metabolite was detected at any time. The sum of diflubenzuron and its metabolites in the litter layer was, on average, 0.7mg kg−1 both 1 week and 1 month after the application. The next year, however, it had increased to 1.4 mg kg−1. Diflubenzuron and its metabolites were not detected in the humus layer. The amount of diflubenzuron residues in the pine needles was, on average, 3.0 mg kg −1 1 day after the application, but in 2 months the level had decreased to 0.2‐0.3 mg kg −1 or was not detectable. The following year the sum of diflubenzuron and its metabolites in two pine‐needle samples was 0.3 and 1.6 mg kg −1. The sum of diflubenzuron and its metabolites in wild mushrooms was, on average, 0.07 mg kg −1 1 week after the application, but the following year no residues were detected. No residues were found in the boletus samples. The residues of diflubenzuron and its two metabolites in bilberries totalled, on average, 0.2 mg kg −1 1 day after the application, and 6 μg kg −1 the following year. The sum of diflubenzuron and metabolites in cowberries was, on average, 0.2 mg kg −1 1 month after application.
Synthesis and plant growth regulating properties of derivatives of alkyl 3‐benzoyl‐3‐(3‐chloro‐4‐substituted phenyl)‐2‐methylcarbazates
Authors: Bergmann Harry , Strumpf Thomas , Lyr Horst
Published: November 2006

Alkyl 3‐benzoyl‐3‐(3‐chloro‐4‐substituted‐phenyl)‐2‐methylcarbazates (isoelectronic analogues of wild oat herbicides) have plant growth regulating properties for various weeds and crops. Some derivatives of carbazates, bearing halogen in the 4‐position of the phenyl group, have been shown to have the highest activity of the prepared compounds.
Insecticide/acaricide resistance: Industry's efforts and plans to cope
Authors: Voss Günther
Published: November 2006

The ‘Insecticide Resistance Action Committee’ (IRAC) is a consultative body to GIFAP on all technical/scientific matters relating to insecticide/acaricide resistance. IRAC coordinates industrial efforts to prolong the life of insect control agents, and fosters working relationships with non‐industrial research workers engaged in solving resistance problems. The activities of IRAC indicate that industry (1) is concerned about resistance reducing the benefit/cost ratio of valuable products, (2) is fully aware of existing and potential resistance problems in all areas where insecticides are being used, (3) plans to improve resistance monitoring in major crop/pests systems suffering from or being threatened by resistance in the field, and (4) is prepared to cooperate with external research institutions on carious practical and conceptual aspects.
Phenoxy ester herbicide identification and analysis
Authors: Noble Alan
Published: November 2006

A test for the identity of specific phenoxy ester herbicides was required. Work with packed column and capillary GLC showed that the retention times could be used to identify major ester components. An esterification method with acetyl chloride produced a mean yield of 98% with a range of phenoxy acids and alcohols. This method could be used to produce standards for the specific quantitative analysis of esters in formulations.
Catalytic hydrolysis of quinalphos on homoionic clays
Authors: Pusino Alba , Gessa Carlo , Kozlowski Henryk
Published: November 2006

The decomposition of quinalphos, O,O‐diethyl O‐quinoxalin‐2‐yl phosphorothioate, on homoionic Cu(II)‐, Fe(III)‐, Al‐, Na‐, K‐ and Cabentonites in hydroalcoholic solution has been investigated. The results show that the hydrolysis of the pesticide may involve two different mechanisms, both depending on the nature of the exchangeable cations. The pesticide hydrolyses to 2‐hydroxyquinoxaline on the Cu‐, Fe‐ and Al‐clays, whereas O‐ethyl O‐quinoxalin‐2‐yl thiophosphoric acid is the main product of hydrolysis on the Na‐, K‐ and Ca‐clays. The de‐ethylation reaction appears to be favoured by the hydrolysis of the Na‐and K‐clays. A bidentate complex formed by quinalphos and the interlayer exchangeable cations may be responsible for the formation of 2‐hydroxyquinoxaline. The presence of this product in the interlamellar region of clay was shown by infrared and X‐ray data.
Use of novel approaches for designing safer drugs in insecticide research: Soft alkylating agents
Authors: Matolcsy GyöRgy , Bélai Iván , Fónagy Adrien , Varjas LáSzló , Tombor Agnes , Laczay Ildikó
Published: November 2006

Based on the analogy between anticancer drugs and insect chemosterliants, both of them acting by virtue of their alkylating capacity, chloromethyl carboxylates (described by Bodor and co‐workers as potential anticancer drugs of the soft alkylating agent type) including the chloromethyl ester analogues of the juvenoids hydroprene and methoprene were prepared and tested for chemosterilant and morphogenetic juvenile hormone activity. While the chloromethyl esters of some simple carboxylic acids were inactive in this respect, the juvenoid chloromethyl esters revealed both chemosterilant and morphogenetic activity against Dysdercus cingulatus comparable with that of the known juvenoids hydroprene and methoprene. At the same time their activity against Pieris brassicae showed a sharp drop compared to the ‘parent’ compounds. The results suggest a species‐dependent rate of enzymatic hydrolysis of the chloromethyl ester group as a possible reason for their selective action. Thus, the chloromethyl ester group might function as a ‘selectivity factor’).
Factors affecting the foliar absorption and redistribution of pesticides. 2. Physicochemical properties of the active ingredient and the role of surfactant
Authors: Stevens Peter J. G. , Baker Edward A. , Anderson Nicholas H.
Published: November 2006

Uptake into and local translocation within leaves sprayed with radiolabelled glucose and fourteen agrochemicals dissolved in aqueous acetone has been measured for four species (maize, rape, strawberry and sugar beet). Uptake during droplet drying (2‐3 min after application) was small (mean value 4% of applied compound) and similarly only small amounts of compounds were found in the epicuticular wax 24 h after application. Total uptake into the leaf ranged from 1‐97% at 24 h, depending on compound and on species. Enhancement of uptake by addition of a non‐ionic surfactant was very variable. Regression analysis and graphical plots showed that uptake was inversely related to melting point, except into sugar beet, and for this species and for strawberry, uptake was also inversely related to water solubility. Both uptake and translocation passed through a maximum with increasing partition coefficient in most cases, with optimum values of log (partition coefficient) of c. 0 and 1.5‐2.2 respectively. The uptake of the four polar compounds used also appeared to be affected by their hygroscopicity and state of ionisation.
The fungitoxicity of chlorophenols to the pathogenic fungi, Fusarium oxysporum and Rhizoctonia solani: A structure‐activity relationship study
Authors: Cohen Ephraim , Gamliel Avraham , Katan Jaacov
Published: November 2006

Inhibition of hyphal growth of Fusarium oxysporum f. sp. melonis and Rhizoctonia solani by a series of chlorinated phenols was studied. Excluding the 2‐chloro derivative, R. solani was found to be more sensitive to chlorophenols than F. oxysporum. When the octanol‐water partition coefficients (expressed as π values) of the compounds were plotted against the effective median dose (ED50), a positive and linear relationship was disclosed. Fungitoxicity was enhanced with the increase in the number of chlorine substituents and their position on the phenol ring was an important factor in determining the biological activity. Toxicity was related to the undissociated (hydrophobic) state of the molecule. The toxicity of the chlorinated phenols varied with the pH of the medium: the relationship of this to the pKa of the compound indicated that permeation of the toxicant through the fungal cell walls and plasma membranes increased with increasing concentration of nonionized molecules. The different inhibition pattern of pentachlorophenol is discussed in light of its property as a lipophilic ion.
Neurotox '88‐An international symposium on neuropharmacology and pesticide action
Authors: Shukla S. P. , Tripathi G.
Published: November 2006

Organised by the Society of Chemical Industry on 10‐15 April 1988, at the University of Nottingham.

The following are summaries of posters presented at Neurotox '88, and as so presented, they are entirely the responsibility of the authors and do not reflect the views of the Editorial Board of Pesticide Science.
Photochemical transformation of phosalone
Authors: Walia S. , Dureja P. , Mukerjee S. K.
Published: November 2006

The photodegradation of the insecticide phosalone has been investigated under UV and simulated solar light conditions. Irradiation of phosalone in solvents such as hexane and methanol yielded a new photoproduct, dechlorophosalone formed as a result of photodechlorination of phosalone. Irradiation in methanol afforded, besides the usual hydrolytic products, three new compounds: phosalone‐oxon; O,O‐diethyl S‐methyl phosphorodithioate; and 6‐chloro‐3‐methoxymethyl‐2‐oxobenzoxazoline. Photolysis of phosalone in the solid state as a thin film on a glass surface produced a number of photoproducts including two new compounds: 6‐chloro‐3‐mercaptomethyl‐2‐oxobenzoxazoline and its dimeric disulfide. Under controlled laboratory conditions, the half lifes of disappearance of phosalone in UV and simulated solar light were found to be 2.5 and 4.75 days on the soil surface and 4.75 and 8.5 days on the glass surface.
The determination of coumaphos residues in honey by HPTLC with in‐situ fluorimetry
Authors: Barbina Taccheo M. , De Paoli Mauro , Spessotto Claudio
Published: November 2006

An HPTLC method for determining fluorimetrically the residues of coumaphos in honey samples is described. The active ingredient is solid phase extracted with a C‐18 disposable column and determined densitometrically on HPTLC pre‐coated silica plates. The method does not require additional clean‐up steps, is extremely quick and can easily be adapted to routine determinations of a large number of samples. The determination limit is 0‐01 mg kg−1 and recoveries are above 87%.
Inhibition of chitin synthesis in an insect cell‐line
Authors: Spindler‐Barth Margarethe , Spindler Klaus‐Dieter , Londershausen Michael , Thomas Herbert , Ag Bayer
Published: November 2006

An epithelial cell‐line from Chironomus tentans, able to synthesise chitin in considerable amounts, was used as a test system to study the influence of tunicamycin (I20=750 nM), the benzoylphenylurea derivative SIR 8514 (I50=100 nM), oligomycin (I50=200 nM), avermectin (I50=5 μM) and nikkomycin Z (I50,=50 μM) on the rate of glucosamine incorporation into chitin. Chitin synthesis was diminished by application of 20‐hydroxyecdysone.
Plant growth regulating activity of aromatic aminophosphonates and their short peptides
Authors: Kafarski Pawel , Lejczak Barbara , Slesak Edward , Przetocki Jacek
Published: November 2006

Phosphonic acid analogues of phenylalanine, tyrosine and 3,4‐dihydroxyphenylalanine exhibited interesting plant growth regulatory properties when tested on Cucumis sativus L. Depending on the chemical structure, they slightly inhibited or strongly promoted the growth of C. sativus roots, while their influence on hypocotyls was negligible. Phosphono peptides based on these acids showed less significant plant growth regulating activity.
Studies on the systemicity of [14C]metalaxyl in cowpea (vigna unguiculata (L.) walp.)
Authors: Singh Uma S.
Published: November 2006

[14C]metalaxyl applied to seeds, roots and leaves of cowpea was readily taken up by all plant parts and a major fraction of it was retained within the treated leaves and seeds but not in the roots. The fungicide exhibited ambimobility inside the plant. When applied to the middle of leaflets, metalaxyl mobilised towards proximal and distal parts of the leaflet. Intraleaflet movement seemed to result from translocation through veins and diffusion through cell walls and intercellular spaces. Accumulation of metalaxyl at tips and margins of primary leaves followed application to roots. Metalaxyl was readily extracted from most plant parts except cotyledons and only 0.8% of the fungicide applied as a seed treatment was recovered from 50‐day‐old plants.
On‐column esterification and N‐methylation of carbetamide with N,N,N‐trimethylanilinium hydroxide
Authors: Ogierman Leonard
Published: November 2006

Transesterification and N‐methylation of carbetamide was carried out using N,N,N‐trimethylanilinium hydroxide as an alkylation reagent. The final product of the on‐column methylation appeared as the dimethyl derivative of carbetamide which was qualitatively identified and quantitatively determined by means of gas‐liquid chromatography. The standard methyl N‐methylcarbanilate was analytically identified by a mass spectrometric method.
The pyrethrins and related compounds. Part XXXV. Esters of aryl‐substituted cyclopentane alcohols and analogues
Authors: Farnham Andrew W. , Janes Norman F. , Khambay Bhupinder P. S.
Published: November 2006

Synthesis of a range of 1‐, 2‐and 3‐phenyl, benzyl and phenethyl substituted cyclopentanols and cyclopentylmethyl alcohols and related unsaturated compounds is reported. Results of bioassays of their esters with known pyrethroidal acids against two species of insect lead to recognition of some structure‐activity relationships in this series. The distance and relative orientation between the alcoholic and aryl functions appears crucial, but in other respects the nature of the spacer group between them is less important. The most effective alcoholic components are based on cyclopentenes.
Insecticide application and insect control using a drip irrigation delivery system
Authors: Royer Tom A. , Edelson J. V. , Bogle C. R. , McCrate S.
Published: November 2006

The effect of pesticide delivery on the eficacy of equivalent rates of several insecticides was investigated by comparing broadcast foliar sprays to applications via drip irrigation in bell peppers, celery and cantaloupe.

Oxamyl applied through the drip line controlled green peach aphids, Myzus persicae (Sulzer) in bell peppers, Capsicum annum L. ‘Tambel‐2’, throughout the growing season, but did not control pepper weevil, Anthonomus eugenii Cano populations. Foliar applications of oxamyl controlled both insects. Foliar applications of cyromazine controlled leafminers, Liriomyza spp. in bell peppers late in the growing season. Drip applications of cyromazine suppressed leafiminers early in the growing season, but were ineffective in later applications.

In cantaloupe, Cucumis melo L. ‘Magnum 45’, populations of melon aphids, Aphis gossypii Glover were suppressed with oxamyl and oxydemeton‐methyl, but foliar applications were significantlymore effective in achieving reductions. Oxamyl controlled leafmminers in cantaloupe with both application methods after the first evaluation, but control was superior with foliar applications at the second evaluation.

Oxamyl suppressed populations of the western potato leafhopper, Empoasca abrupta DeLong in celery, Apium graveolens L. ‘5270’, using either delivery method. Oxamyl residues in drip‐applied celery were higher than USA regulations would allow, thus the rate of application would have to be modified.

A cost analysis comparing delivery systems indicated that a drip‐applied insecticide application was much less expensive than a foliar application with air or ground equipment. However, control was limited to phloem‐feeding insects, was slower in attainment, and at best, was equal to or less than that obtained with a foliar spray.
Development of insecticide resistance and cross‐resistance in fenvalerate‐, and cypermethrin‐selected strains of Earias vittella(fab.)
Authors: Saini R. K. , Chopra N. P. , Verma A. N.
Published: November 2006

First‐instar Earias vittella (Fab.) larvae were selected with fenvalerate and cypermethrin for 15 successive generations in the laboratory at 28(± 1)°C. The insect developed 7.8‐fold resistance to fenvalerate and no resistance to cypermethrin. The fenvalerate‐selected strain developed 2800‐fold and 1200‐fold cross‐resistance to endosulfan and carbaryl, respectively. This strain, however, did not manifest cross‐resistance to the organophosphorus insecticides, quinalphos, fenitrothion, monocrotophos and malathion, or to the synthetic pyrethroid, cypermethrin. The cypermethrin‐selected strain acquired 5‐, 4‐, and 3‐fold cross‐resistance to endosulfan, fenvalerate and carbaryl, respectively and no cross‐resistance to the above organophosphorus insecticides.
The fate of the rodenticide flocoumafen in the rat: Retention and elimination of a single oral dose
Authors: Huckle K. R. , Hutson D. H. , Logan C. J. , Morrison B. J. , Warburton P. A.
Published: November 2006

A single oral dose of 0.14 mg kg−1 of [14C] flocoumafen to rat, which gave a transient, non‐lethal, effect, was rapidly absorbed, radioactivity appearing in the blood maximally at 4 h and falling to half maximum value by 8 h. The maximum effect on prothrombin time was at 24 h and the value returned to normal by 48 h. Elimination of radioactivity was very slow, with less than 0.5% of the dose in the urine up to 7 days after dosing, and 23‐26% in the faeces (more than half of which appeared in the first 24 h). Most of the administered radioactivity (74‐76%) was retained 7 days after dosing. Approximately half of the dose was in the liver; it was eliminated with a halflife of 220 days. At 48 h after dosing, most of the hepatic radioactivity comprised unchanged flocoumafen. Treatments of flocoumafen‐dosed rats with warfarin or with cytochrome P450‐inducing doses of phenobarbitone were without effect on the hepatic residue of flocoumafen.
Some investigations of suspoemulsions
Authors: Wigger August , Gückel Walter
Published: November 2006

‘Suspoemulsions’ (SE) is the term used to describe combined formulations of solid and liquid active ingredients as dispersed systems. The parameters influencing an SE were investigated with reference to four examples (one solid and three liquid products) in various mixing ratios. Apart from the type and amount of the partners and the energy dissipation density used, the recipe and viscosity particularly had effects on the formation and properties of an SE. The solid particles in the suspension promoted the comminution of the liquid phase. However, they had practically no influence on the flow behaviour in the three degrees of comminution fineness investigated. The causes of the phenomena discovered are discussed. The storage stability of the SE was equal to that of suspension concentrate (SC) formulations. The advantageous effect of the addition of a thickener on storage stability was similar to that in the case of an SC.
A colorimetric version of the CIPAC method for measuring dilute emulsion stability
Authors: Hill Alistair C. , Twort Anthony R.
Published: November 2006

The characterisation of emulsions at dilution rates greater than the 1:20 used in most international specifications for agrochemical formulations is becoming increasingly important. The internationally‐agreed CIPAC MT 36.2 test depends upon the determination of the shift in bulk concentration between the upper and lower halves of an emulsion after a period of standing. An analytical method specific to the active ingredient is stipulated. This paper reports an investigation of the use of CIPAC MT 36.2 with an emulsifiable concentrate (EC)‐soluble dye which allows a colorimetric finish. This new method should be applicable to almost all ECs, and uses less costly instrumentation than the standard method. It could therefore allow more convenient use of CIPAC MT 36.2 for formulation development purposes. The limitations and range of applicability of the new method are discussed. For ECs of poor spontaneity it is shown that emulsion stability is strongly influenced by the emulsification technique used. Techniques within the frame of CIPAC MT 36.2 have been discovered which give repeatable results for such ECs.
Fenvalerate residues on cattle hair coat from impregnated ear tags
Authors: Yeung Jupita M. , Colwell Douglas D. , Shemanchuk Joseph A.
Published: November 2006

A simple small‐scale method for the determination of fenvalerate residues on cattle hair by gas–liquid chromatography with electron capture detection was developed and applied to the determination of fenvalerate residues from BovaidR ear tags. Recoveries were found to be 96–104% at 10–100 μg g−1 levels of fenvalerate. The minimum detection limit of this method was 1 pg g−1. With one ear tag, fenvalerate was adequately distributed over the entire body and persisted for at least 80 days on the hair of cattle.
Fate of carbofuran in model rice/fish ecosystems
Authors: Jinhe Sun , Jianying Gan , Ziyuan Chen
Published: November 2006

The distribution and fate of [14C]carbofuran were studied in model earlyseason rice/fish and late‐season rice/fish ecosystems after its application by respectively soil incorporation and broadcasting. The differences observed in the behaviour of the insecticide in these two rice/fish ecosystems indicated the important effect of the different application methods on the fate of the chemical in the environment. The radioactive residues in the paddy water, rice plants and fish were much lower when the pesticide was incorporated into the soil surface layer. An obvious vertical movement of carbofuran residues occurred in the paddy soil profile. Bound residues constituted the majority of the residues in the paddy soil, rice plants and fish tissues. 3‐Hydroxy‐ and 3‐ketocarbofuran and carbofuran phenol were tentatively identified as the main degradation products in the paddy water, paddy soil, rice plants and fish.
Off‐target deposition and drift of aerially applied agricultural sprays
Authors: Riley Christopher M. , Wiesner Charles J. , Ernst William R.
Published: November 2006

Off‐target drift and deposition of aerially applied deltamethrin sprays in an agricultural situation were determined using stainless steel (20 × 40 cm) ground deposit samplers and ‘Rotorods’. Off‐target spray deposition decreased exponentially with distance in situations where applications were made in winds with speeds equal to, or just above, maximum label limits for aerial application (8 km h−1). The results are compared with those of previous studies. The effectiveness of a 100‐m ‘no spray’ buffer zone in reducing off‐target deposit is evaluated.
Photolysis of quinalphos in ethanolic solution
Authors: Pusino Alba , Gessa Carlo , Frigerio Alberto
Published: November 2006

Photolysis of quinalphos, O,O‐diethyl O‐(quinoxalin‐2‐yl) phosphorothioate (I), in ethanolic solutions yields two products, O,O‐diethyl O‐(3‐ethoxy‐quinoxalin‐2‐yl) phosphorothioate (II) and O,O‐diethyl O‐(3‐(1‐hydroxyethyl)‐quinoxalin‐2‐yl) phosphorothioate (III). Both products derive from the reaction of photo‐excited quinalphos molecule with the solvent. The reactions follow first‐order kinetics. A mechanism that accounts for the formation of the above mentioned products is proposed.
Fungicidal activity of a series of phenyl pyridyl ketoximes and their O‐acetyl derivatives
Authors: Massolini Gabriella , Kitsos Mikes , Gandini Carlo , Caccialanza Gabriele
Published: November 2006

The free oximes and acetyl derivatives of a series of 4‐substituted phenyl pyridyl ketones were prepared and tested in vitro and in vivo against fungal plant pathogens of different taxonomic classes.

All compounds exhibited an interesting activity against some or all of the test fungi. The best results were given by the acetyl derivatives.
Synthesis and toxicological properties of some alkyl and aryl 3,4‐methylenedioxyphenyl N,N′‐thio‐bis‐N‐methylcarbamates
Authors: Wallace Guillermo C. , Zerba Eduardo N.
Published: November 2006

A series of asymmetrical thio‐bis‐N‐methylcarbamate derivatives were synthesised by combining 3,4‐methylenedioxyphenyl N‐methylcarbamate with different N‐methylcarbamates. Some of these derivatives combined good insecticidal activity against the housefly with reduced acute oral toxicity to mice.

The thio‐bis‐N‐methylcarbamates obtained exhibited a lower anti‐cholinesterase activity than the more toxic of the two carbamate moieties contained in each combination. The weak synergism of piperonyl butoxide on the insecticidal activity of the derivatives suggests the possibility of a self synergism phenomenon caused by the 3,4‐methylenedioxyphenyl group.
Effect of environment on efficacy of seed‐treatment fungicides for control of common bunt in spring and winter wheat
Authors: Gaudet Denis A. , Puchalski Byron J. , Entz Toby
Published: November 2006

The effectiveness of protectant and systemic seed‐treatment fungicides for control of common bunt caused by Tilletia caries (DC.) Tul. and T. foetida (Wallr.) Liro. in spring and winter wheats was evaluated at different locations from 1981 to 1987. The fungicides, tested at two rates (I and II), were of three types: (1) fungicides which were effective in all years and locations at levels approaching 100%; (2) fungicides which provided uniform bunt control in all years and locations at levels less than 100%, and (3) fungicides which were sensitive to environmental conditions within years and locations. Fungicides which were effective in all years and locations at levels approaching 100% were triadimenol II, myclobutanil I and II, diniconazole I and II, and flutriafol II, on spring wheat, and etaconazole and furmecyclox in the seed‐(SD), and seed‐ and soil‐ (SS) inoculation treatments, and triadimenol in the SD‐inoculation treatment on winter wheat. Fungicides which provided uniform bunt control in all years and locations at levels less than 100% included flutriafol I and triadimenol I in spring wheat, applied at rates below optimal, and carboxin dust and nuarimol on winter wheat, in SS‐ and SD‐inoculation treatments. Fungicides which were sensitive to environmental conditions within years and location included maneb, carboxin I and II on spring wheat, and carboxin solution and dust in the SD‐ and SS‐inoculation treatments on winter wheat. Comparisons of bunt levels in fungicide treatments with those in the infested controls revealed that some fungicides did not perform consistently across years and locations. Variation in efficacy of fungicides was classified into three types: (1) random environmental variation which occurred with all fungicide treatments tested; (2) non‐random environmental variation which occurred with maneb and carboxin fungicides, and (3) variation attributed to increasing bunt severity which occurred with the SS and SD carboxin fungicides used to control bunt in winter wheat. The implications of inadequate protection from currently registered seed‐treatment fungicides on wheat varieties that are highly susceptible to bunt are discussed.
Kinetics of the reaction of the first metabolite of fenitropan with some low molecular weight thiols
Authors: Gullner Gabor , Josepovits Gyula , Mikite Gyula
Published: November 2006

2‐Nitro‐I‐phenylpropen‐3‐yl acetate (NPPA), the first metabolite of the fungicide fenitropan, reacted readily with glutathione in aqueous ethanol solutions at room temperature, producing at least two products. The first reaction step, which is believed to be a bimolecular nucleophilic (Michael) addition, had a strongly pH‐dependent reaction rate.

Second‐order rate constants were calculated for the reactions of NPPA at pH 4 with glutathione and with some other low molecular weight thiols. Nucleophilic reactivity of the reacting thiolate anions is linearly related to the pKa values of the thiols. However, as the concentration of thiolate anion is also determined by the thiol pKa, there is no simple relationship between second‐order rate constants and thiol pKa. Thus the blocking rate of the various essential sulphydryl groups in fungi by NPPA is determined by the sulphydryl pKa values and the ambient pH value.
Design of new melanin biosynthesis inhibitors
Authors: Omata Kenzo , Tomita Hirofumi , Nakajima Tetsuo , Natsume Bunji
Published: November 2006

Structural requirements for melanin biosynthesis inhibition were analysed by comparing known melanin biosynthesis inhibitors (MBIs) and an intermediate of melanin biosynthesis (1,3,8‐trihydroxynaphthalene (1,3,8‐THN)), on the assumption that the enzymatic inhibition by MBIs occurs competitively with the biosynthetic intermediate. On this basis, new chemicals in the form of phthalazine derivatives were designed.

In biological tests, the synthesised phthalazine derivatives showed high activity against rice blast, caused by Pyricularia oryzae Cav. These compounds also inhibited the melanisation of this fungus at a low concentration, which suggested that they are similar to other MBIs in their mode of action.
Insect resistance to insecticides
Authors: Metcalf Robert L.
Published: November 2006

The past 40 years have seen insect resistance to insecticides develop from a scientific curiosity to an immense practical problem that threatens man's ability to control not only the insect pests of agriculture but also the insect vectors that transmit major human and animal diseases. The spread of genes for cross and multiple resistance among insect pests has rendered most of our present insecticides obsolescent and very few novel insecticides are under development as substitutes. The most feasible strategy to maintain adequate control of insect pests is integrated pest management or I P M, in which insecticide management is a useful component. However, much of our present planning for the future of insect control is carried out in ignorance of past failures. We must learn from the past if we are to retain the use of chemical insecticides as a viable component of IPM.
Synthesis and in‐vitro antifungal activity of 6‐trifluoromethyipyrazolo[3,4‐6d]pyrimidin‐4(5H)‐thiones
Authors: Vicentini Chiara B. , Poli Tiziana , Veronese Augusto C. , Brandolini Vincenzo , Manfrini Maurizio , Guarneri Mario , Giori Paolo
Published: November 2006

Twelve 6‐trifluoromethylpyrazolo[3,4‐d]pyrimidin‐4(5H)‐thiones were prepared by the reaction between 4‐thiocarbamoyl‐5‐aminopyrazoles and trifluoroacetic anhydride. They were tested in vitro for antifungal activity against a series of phytopathogenic fungi of different taxonomic classes. The EC50 and MIC values of four compounds were comparable or inferior to those of reference commercial fungicides in controlling Sclerotinia minor, Corticium solani and Phytium ultimum.
The discovery of new chemotherapeutic agents
Authors: Roberts Stanley M.
Published: November 2006

The strategy and tactics behind the discovery of salbutamol (treatment of asthma), β‐blockers (anti‐hypertensives), clavulanic acid (used in antibacterial preparations), buprenorphine (pain‐killer), cimetidine and ranitidine (anti‐ulcer agents) are described in brief.
Use of Bacillus subtilis and Related Organisms as Biofungicides
Authors: Pusey P. Lawrence
Published: November 2006

Use of a strain of Bacillus subtilis (designated B‐3) as a biological control agent is reviewed, with emphasis on the post‐harvest application to stone fruit for control of brown rot caused by Monilinia fructicola. Included are studies on the antifungal peptides (identified as Iturin antibiotics) produced by B‐3, laboratory tests to determine compatibility of the organism with current commercial procedures, and a pilot test on simulated and commercial peach‐packing lines. In the pilot test, B‐3 (2 × 108 to 7 × 108 colony‐forming units kg−1 fruit) in commercial wax was equal to benomyl (1‐2 mg kg−1 fruit) in controlling brown rot. The bacterium was screened for use against other fungal pathogens of stored plant products. In‐vivo activity against fungi was shown for apple rots caused by M. fructicola, Botrytis cinerea, and Glomerella cingulata, and for grey mould of grapes caused by B. cinerea.
Potential of biological control organisms as a source of antifungal compounds for agrochemical and pharmaceutical product development
Authors: Rodgers Paul B.
Published: November 2006

In many cases, the mode of action of micro‐organisms with biological control activity has been found to be the production of metabolites with biocidal activity. Thus, such organisms offer great potential as a source of novel lead compounds for agrochemical and pharmaceutical product development. A range of biological control agents is being developed and out of this research has come several natural products which have been considered for further development. Two examples discussed in some detail are a novel pyridone with fungicidal activity produced by Trichoderma harzianum and a novel metabolite of Bacillus subtilis which has a high level of broad‐spectrum fungicidal activity.
Secondary plant metabolites as targets for genetic modification of crop plants for pest resistance
Authors: Dawson Glenn W. , Hallahan David L. , Mudd Alan , Patel Madhavji M. , Pickett John A. , Wadhams Lester J. , Wallsgrove Roger M.
Published: November 2006

Three genetic manipulation strategies are described for enhancing the effectiveness of secondary metabolites of crop plants in reducing pest and disease damage. Targets for gene transfer studies are secondary metabolites of oilseed rape, lepidopteran sex pheromones and drimane anti‐feedants. Initial work towards isolation of genes for the biosynthesis of drimane anti‐feedants is described.
A note on the mosquito oviposition pheromone
Authors: Dawson Glenn W. , Laurence Brian R. , Pickett John A. , Pile Mary M. , Wadhams Lester J.
Published: November 2006

Mosquitoes of the genus Culex, e.g. Culex quinquefasciatus, release a volatile pheromone from their eggs that induces gravid females to oviposit around the pheromone source. Enantioselective synthesis by the Sharpless epoxidation method and chiral gas chromatography showed the major pheromone component to be (−)‐(5R,6S)‐6‐acetoxy‐5‐hexadecanolide. Shortening the alkyl chain resulted in a loss of behavioural activity, whereas perfluorination of the alkyl chain or substitution of the acetoxy groups with the trifluoroacetoxy group gave active analogues. A simple large scale synthesis was devised to provide material for a fìeld trial. The pheromone, formulated in effervescent tablets, was used to concentrate oviposition in specific breeding sites where the larvae were controlled with a juvenoid‐type insecticide.
Understanding the site of action of photosystem II inhibitors
Authors: Judson Philip N. , Rowson Graham P.
Published: November 2006

It is believed that the different classes of compound which interfere with photosynthesis system II (PS 11) must act by binding at different sites, because they appear to be structurally so dissimilar. However, it can be argued that some of the classes of compound of diverse structural type share very similar external surface features. Now that details about the binding oj PSII inhibitors are becoming available, it will be possible to see how many of the different compound classes actually bind similarly. In future, increasingly detailed knowledge of the structures of potential sites of action will be available. QSAR methods will need to be used together with molecular modelling to be effective tools for agrochemical design.
Insecticide resistance management: Relationship to integrated pest management
Authors: Phillips J. R. , Graves J. B. , Luttrell R. G.
Published: November 2006

Insecticide resistance management (IRM) is a component of integrated pest management (IPM) that has the goal of forestalling resistance development to all insecticides. Since the advent of the organochlorine insecticides in the 1940s, an average of about one class of insecticide has been lost every 10 years because of resistance. Effective insecticides are necessary for optimum IPM and are too important and too expensive a resource to be lost so rapidly. By adhering to the principles of IPM and utilizing other IPM components such as biological and cultural control, IRM has the potential of conserving the susceptibility of pests to insecticides. Although initial attempts of IRM appear to be successful, it is imperative that research to undergird IRM be greatly accelerated.
Mode of action of the fungicide flusilazole in ustilago maydis
Authors: Henry Matthew J.
Published: November 2006

Flusilazole is a potent inhibitor of Ustilago maydis sporidial growth (I50= 20 μg liter−1). Incorporation of [14C]acetate into ergosterol of growing sporidia is inhibited 50% by 0.5 μg liter−1of the fungicide. Inhibition of ergosterol biosynthesis is concomitant with the accumulation of the precursors eburicol, obtusifoliol and 14α‐methylfecosterol. A novel cell‐free assay has been developed to measure the 14α‐demethylation of [3H]dihydrolanosterol. Flusilazole inhibits the cell‐free demethylation with an I50of 15 μg liter−1. These data provide strong evidence that the mode of action of flusilazole is by inhibiting ergosterol biosynthesis through direct inhibition of the 14α‐demethylation of ergosterol precursors.
Conformational and intramolecular hydrogen bonding effects on post‐emergence and pre‐emergence selectivities of herbicidal pyrrole dicarboxylates
Authors: Andrea Tariq A. , Stranz David D. , Yang Alex , Kleier Daniel A. , Patel Kanu M. , Powell James E. , Price Thomas P. , Marynick Dennis S.
Published: November 2006

Dimethyl 2‐methyl‐5‐(chloropyridin‐2‐yl)pyrrole‐3,4‐dicarboxylates in which the chlorine atom is substituted at different positions of the pyridine ring have widely varying biological properties. The 3‐chloro analog (I) is a post‐emergence and pre‐emergence herbicide, the 4‐ and 5‐chloro analogs (II, III) are post‐emergence herbicides but not pre‐emergence, and the 6‐chloro analog (IV) is inactive. Computer graphic and molecular mechanics analyses of their molecular conformations showed that the 4‐ and 5‐chloro analogs adopt a coplanar, intramolecularly hydrogen bonded conformation whereas the 3‐chloro analog does not. High‐level quantum mechanical calculations of the conformational preferences of related model systems were in agreement with these results. Based on this, II and III were predicted to have higher octanol/water partition coefficients relative to I, leading to higher soil binding and weaker xylem transport, hence their observed weaker pre‐emergence activities. Experimental measurements of octanol/water partition coefficients, soil binding, and infrared hydrogen bonding studies verified these predictions. Molecular modeling techniques are usually used for designing compounds to fit enzyme active sites and designing putative receptor models. This study demonstrates the usefulness of these techniques for dealing with transport problems.
Effects of metaldehyde and acetaldehyde on feeding responses and neuronal activity in the snail, lymnaea stagnalis
Authors: Mills Janette D. , McCrohan Catherine R. , Bailey Stuart E. R. , Wedgwood Marilyn A.
Published: November 2006

The pond snail Lymnaea stagnalis was fed on maize pellets containing metaldehyde. With increasing concentration of metaldehyde there was a decrease in the meal length, number of bites per meal and amount of pellet eaten. The irregularity of biting and the amount of time spent pausing during the meal increased.

Meals on maize pellets in the presence of acetaldehyde (one of the metabolites of metaldehyde) were shorter than control meals on maize pellets alone.

The symptoms of poisoning after ingestion of metaldehyde or in the presence of acetaldehyde were similar. There was an increase in mucus secretion. Animals showed muscular spasms, undirected mouthing movements and uncoordinated locomotion. This was followed by a period of immobility.

The isolated central nervous system of L. stagnalis was used to study the effects of metaldehyde and acetaldehyde on the neural activity underlying feeding. Application of metaldehyde or acetaldehyde led to an increase in firing activity and development of paroxysmal depolarising shifts in buccal motoneurons. It is argued that this type of activity could explain some of the symptoms of poisoning seen in the whole animal after ingestion of metaldehyde, and that acetaldehyde may be responsible for some of the toxic effects of metaldehyde.

These results suggest that the CNS of L. stagnalis provides a useful model for screening molluscicides for their effects on a functional neuronal network.
The origins of selectivity and performance of a new pre‐emergence bleaching herbicide, WL 110547. Part I: Factors affecting uptake
Authors: Grayson B. Terence , Webb James D. , Deveson Malcolm R. , Blackman Peter G.
Published: November 2006

A novel compound, 1‐(3‐trifluoromethylphenyl)‐5‐phenoxy‐1,2,3,4‐tetrazole (WL 110547) is a pre‐emergence bleaching herbicide with selectivities in certain crops. These selectivities and the weed‐control spectrum are derived, in part, from features which influence the uptake of WL 110547 into sensitive tissue. WL 110547 is strongly adsorbed to soil with measured Koc values in the range 1500‐2500 and, following application, is confined to the surface layers of soil, especially when the organic matter content is high. Some plant species have anatomical features which protect their developing leaf tissue from contact with the soil during emergence and thus escape direct contact with these treated layers. Furthermore, some of these plants are deeply rooted and thus there is little opportunity for sufficient uptake of WL 110547 to cause a phytotoxic effect.

However some weeds, especially annual dicotyledons, germinate only from shallow depths and, during emergence, their cotyledons or leaves are in contact with the soil. In soils treated with WL 110547 they can thus absorb phytotoxic concentrations of herbicide directly into their cotyledons or leaves. Additional uptake may also occur through roots near the surface and allow WL 110547 to be translocated via the transpiration stream to the site of action in cotyledons and leaves and enhance phytotoxicity.

Knowledge of the features controlling uptake, combined with a knowledge of intrinsic susceptibility, have allowed an understanding of the spectrum of weed control and the selectivities between weeds and crops.
Non‐target effect of herbicides: I. effect of glyphosate and hexazinone on soil microbial activity. Microbial population, and in‐vitro growth of ectomycorrhizal fungi
Authors: Chakravarty P. , Chatarpaul L.
Published: November 2006

The effects of two herbicides, glyphosate (as a 359 g litre−1 SL) and hexazinone (as a 50gkg−1 granule) on soil microbial population, carbon dioxide evolution, and in‐vitro growth of five species of ectomycorrhizal fungi were investigated. Glyphosate at 0–54 and 3.23 kg a.i. ha−1 and hexazinone at 1. 2 and 8 kg a.i. ha−1 did not reduce soil microbial population or carbon dioxide evolution in the long term (6 months). However, there was a significant short‐term (2 months) effect of glyphosate on both fungal and bacterial counts at the 0.54 kg ha−1 treatment. In in‐vitro tests, Cenococcum graniforme. Hebeloma crustuliniforme and Laccaria laccata were more susceptible to both herbicides than was Suillus tomentosus. which was, in turn, more susceptible than Paxillus involutus. The growth of all five ectomycorrhizal fungi was significantly reduced when subjected to concentrations above 50 μl formulation litre−1 (glyphosate) or 50 μg formulation litre−1 (hexazinone).
Non‐target effect of herbicides: II. The influence of glyphosate on ectomycorrhizal symbiosis of red pine (Pinus resinosa) under greenhouse and field conditions
Authors: Chakravarty P. , Chatarpaul L.
Published: November 2006

The effects of the herbicide glyphosate [N‐(phosphonomethyl)glycine]on seedling growth of Pinus resinosa and on the ectomycorrhizal development of the symbiotic fungus Paxillus involutus were investigated under greenhouse and field conditions. Glyphosate at 0–54 and 3–23 kg ha−1 did not reduce seedling growth or ectomycorrhizal development under greenhouse conditions. There was no seedling mortality due to glyphosate treatment at either rate. Under field conditions, seedling growth of P. resinosa and ectomycorrhizal development of P. involutus were not affected by the above rates. Seedlings (46–48%) failed to survive in non‐glyphosate‐treated plots, presumably because of weed competition, whereas all survived in glyphosate‐treated plots. All the non‐mycorrhizal seedlings were colonized bv indigenous mvcorrhizal fungi within 2 months after planting in both control and glyphosate‐treated plots. The injection rates varied from 74–86 %.
Effect of 4‐amino‐6‐methyl‐3‐phenylamino‐l,2,4‐triazin‐5(4H)‐one on the lignification process catalysed by peroxidase from lupin (lupinus albus)
Authors: Muñoz Romualdo , Martinez‐Martinez Antonio , Ros‐Barcelo Alfonso , Pedreño Ma Angeles
Published: November 2006

The molecular action of herbicides with a triazine structure, such as atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐1,3,5‐triazine) and metribuzin (4‐amino‐6‐tert‐butyl‐3‐methylthio‐1,2,4‐triazin‐5(4H)‐one), has been related to their inhibition of the electron carrier system between chloroplastic photosystems II and I.

This report provides evidence that 4‐amino‐6‐methyl‐3‐phenylamino‐1,2,4‐triazin‐5(4H)‐one, a recently synthesised triazine, structurally analogous to metribuzin, causes a powerful inhibition of the cell‐wall lignification catalysed by peroxidase from lupin. The two reactions involved in this lignification process are: oxidative polymerisation of coniferyl alcohol and the generation of hydrogen peroxide at the expense of NADH oxidation.