bluuebunny/crossref_metadata_2025 huggingface dataset:
The evaluation of permethrin for wood preservation
Authors: Berry Roger W.
Published: November 2006

The toxicity of the synthetic pyrethroid permethrin (NRDC 143) to a range of wood destroying insects has been investigated. In tests using Hylotrupes bajulus, Anobium punctatum, Lyctus brunneus and Reticulitermes santonensis permethrin showed a similar order of toxicity to that of gamma‐BHC. Although the toxicity of permethrin to adult A. punctatum was of the same order as that of gamma‐BHC, the toxicity to larvae was rather lower. The implications of these results are discussed and it is concluded that, subject to further field evaluation, permethrin could provide an alternative to gamma‐BHC and dieldrin in wood preservatives.
Substituted 3‐furamides with specific activity against basidiomycetes
Authors: Pommer Ernst‐Heinrich , Zeeh Bernd
Published: November 2006

Substituted furanilides and furamides show very good activity against Basidiomycetes. Whilst N‐cyclohexyl‐x‐methyl‐3‐furamides (where x‐ is one or more of the vacant positions in the furan ring) further substituted on the amide nitrogen have specific activity against Basidiomycetes (e.g. Ustilago nuda, U. scitaminea, Tilletia tritici and Rhizoctonia solani), N‐cyclohexyl‐N‐methoxy‐2,5‐dimethyl‐3‐furamide also gives good control of other classes of fungi (e.g. Fusarium nivale and Helminthosporium gramineum). This compound is to be developed under the Code Number BAS 389 F as a mercury‐free seed dressing alone or in combination with other fungicides.
Confirmation of perfluidone residues in rice by gas‐liquid chromatography following the formation of derivatives
Authors: Tafuri Francesco , Businelli Mario , Patumi Maurizio , Marucchini Cesare
Published: November 2006

A simple and sensitive method for the confirmation of perfluidone residues in rice grains is described. The procedure involves extraction, purification on an anionexchange resin, chlorination, methylation and gas‐chromatographic analysis with electron capture detection. The recoveries from fortified rice grains varied from 84.0 to 92.4% in the range 0.01–0.20 mg/kg. The sensitivity was such that perfluidone could be detected down to a level of 0.005 mg/kg. The method can be used for confirmation of perfluidone quantitatively as well as qualitatively.
Routine methods for analysis of organophosphorus and carbamate insecticides in soil and ryegrass
Authors: Holland Patrick T.
Published: November 2006

The organophosphate insecticides dichlorvos, trichlorphon and isofenphos have been extracted from soil and ryegrass by blending with acetone+ benzene (19+1, v/v) and charcoal. After filtering, water and waxes were precipitated from the extract at − 78°. The extracts were analysed for insecticide by gas chromatography using alkali flameionisation detection. Trichlorphon was converted to the acetate by on‐column acetylation. Recoveries ranged from 73 to 93% for levels of insecticide from 0.1 to 10mg/kg. The carbamate insecticides methomyl and carbofuran plus the metabolite 2,3‐dihydro‐3‐hydroxy‐2,2‐dimethylbenzofuran‐7‐yl methylcarbamate have been extracted from soil and ryegrass samples by shaking with acidified ammonium acetate. Following filtration and neutralisation, the aqueous phase was extracted with dichloromethane. The carbamates in the extracts were determined by gas chromatography using on‐column trans‐esterification to methyl methylcarbamate. Recoveries ranged from 79 to 97% for levels of insecticide from 0.1 to 10 mg/kg.
A farmer's approach to the socio‐economic aspects of crop protection
Authors: Fell Henry R.
Published: November 2006

The period since 1945 has been one of extraordinary development in British agriculture. A period during which the science of Crop Protection has advanced from practically nothing to where it is today—an accepted and essential part of everyday farming. The speed of these developments has put pressure on the industry and on the individual farmer. At the same time the economic climate of the 1960's has sharpened the search for efficient, low‐cost production. The farmer has no choice but to use every weapon in his armoury. Safeguards against misuse of chemicals seem to be basically satisfactory up to the point of sale. There is, however, the basic point of whether the food producer has grown to be too dependent on chemical control, whilst neglecting good husbandry, which may be both cheaper and more effective.
The metabolism of the herbicide flamprop‐methyl in wheat
Authors: Roberts Terry R.
Published: November 2006

The metabolism of the wild oat herbicide flamprop‐methyl, methyl (±)‐2‐[N‐(3‐chloro‐4‐fluorophenyl)benzamido]propionate, in spring wheat grown to maturity has been studied under glasshouse and outdoor conditions. [14C]‐Flamprop‐methyl labelled separately in the halophenyl ring and the carbonyl of the benzoyl group was used. The major metabolite formed in plants was the corresponding carboxylic acid, II, which also occurred as conjugates. Other minor metabolites detected under glasshouse conditions only were the 3‐ and 4‐hydroxybenzoyl analogues of flamprop‐methyl and 3′‐chloro‐4′‐fluorobenzanilide. The soil in which the plants were grown contained residues comprising mainly flamprop‐methyl and II together with smaller amounts of unidentified polar material.
An equation for computing concentration‐time products of 1, 2‐dibromoethane (EDB) gas during fumigation
Authors: Swaine Gordon , Corcoran Robert J. , Pepper Patricia M. , Cranny Anne E. , Davey Marguerite A.
Published: November 2006

The concentration of 1, 2‐dibromoethane (EDB) gas in the air space during fumigation can be expressed by the empirical equation c = exp [k(t+ I)b]. In this equation c is the concentration of EDB in g/m3 and t is the lapsed time in minutes; k is the natural log of the nominal dosage and b is a parameter which depends on the contents of the fumigation chamber. The b value is obtained from the linear relationship In [(In c)/k] = b In (t+1). The concentration‐time product is obtained from the integral
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DDT‐resistant mosquito strains with cross‐resistance to pyrethroids
Authors: Prasittisuk Chusak , Busvine James R.
Published: November 2006

Various DDT‐resistant strains of mosquito, comprising 8 strains of Aedes aegypti from the Neotropics (tropical and South America) and one each of Anopheles gambiae and An. quadrimaculatus were tested for resistance to pyrethroids. Susceptibility was measured by LT50 values, after exposure to impregnated papers in the cylinders used in the WHO standardised test for adult mosquitoes. DDT‐resistance levels (by comparison with susceptible strains) ranged from × 2 to × 73, with simultaneous low resistance to permethrin (× 1.4 to × 3.4) except in one strain from Guyana which reached × 30. Further comparisons were made with this Guyana strain and one from Salvador with similar DDT‐resistance (about × 70) but low permethrin‐resistance. Tests with methoxychlor and I,I‐di‐(4‐chlorophenyl)‐2‐nitropropane and with the synergist I,I‐di‐(4‐chlorophenyl)‐2,2,2‐trifluoroethanol suggested that a considerable part of the DDT‐resistance of both strains was due to a dehydrochlorination mechanism. Tests with the synergist piperonyl butoxide (PB) suggested that microsomal oxidase systems were also involved, especially in the Guyana strain. The cross‐resistance in both strains extended to 3 other pyrethroids. Addition of the synergist PB had little effect on the Salvador strain, but substantially reduced permethrin‐resistance in the Guyana strain. It is concluded that an unknown mechanism associated with DDT‐resistance confers a low level cross‐tolerance to pyrethroids; this can be substantially augmented by the development of a microsomal oxidase mechanism, as in the Guyana strain.
An Example of Cross‐resistance to Pyrethroids in DDT‐resistant Aedes aegypti
Authors: Chadwick Peter R. , Invest John F. , Bowron Marcus J.
Published: November 2006

Comparisons of the susceptibility of several strains of adult Aedes aegypti were made. Mosquitoes from Bangkok and Jakarta were found to be highly resistant to DDT and resistant to pyrethroids relative to a laboratory strain. A strain from Singapore, where less DDT has been used, was susceptible to DDT and pyrethroids. Two strains from the Caribbean had LC50 values to DDT 3 times that of the reference strain while the LC50 values against bioresmethrin synergised with piperonyl butoxide were 1 1/2 times raised. Another two strains from central Africa were 2 times tolerant of DDT and 1 1/2 times tolerant of bioresmethrin plus piperonyl butoxide. Agents which block DDT‐dehydrochlorinase, esterases and oxidases each caused small increases in the mortality of the Bangkok strain due to DDT and bioresmethrin as well as augmenting toxicity to the susceptible reference strain. It is tentatively suggested that resistance in the Bangkok strain is due to a combination of the actions of these and perhaps other resistance mechanisms.
Studies on the control of groundkeeper potatoes with the soil‐applied herbicides chlorpropham, propyzamide and trifluralin
Authors: Lutman Peter J. W.
Published: November 2006

Chlorpropham, propyzamide and trifluralin were assessed in several trials, to test their potential for the control of groundkeeper potatoes (Solanum tuberosum L.). Chlorpropham was insufficiently active, but trifluralin and propyzamide at doses of 4 kg a.i./ha, or more, reduced and delayed the emergence of potato plants in the summer, after autumn/winter or spring applications. The highest dose (12 kg a.i./ha) prevented many tubers producing plants. Greatest activity was attained when the herbicides completely surrounded the tubers when active growth started in the spring. However, both residue and crop tolerance data indicated that the doses of trifluralin and propyzamide required to control the potatoes were so high that appreciable residues remained in the following summer. These damaged vegetable crops drilled in April and May, and affected cereals planted 12 months after application. Thus there is insufficient margin of selectivity between the doses required to control the potatoes and those tolerated by subsequent crops.
The action of pyrethroids in the insect central nervous system. I. Features of molecular structure associated with toxicity to cockroaches and to their giant fibre axons
Authors: Burt Paul E. , Goodchild Ralph E.
Published: November 2006

To investigate relationships between the molecular structure of pyrethroids and their mode of action, toxicities to adult male Periplaneta americana by topical application and injection were compared with toxicities to their giant fibre nerve axons. From the tests against intact insects it was concluded that: (i) although ED50S ranged from 0.04 to 65 μg/insect, each compound was equally toxic, with one exception, when administered by either route; (ii) esters of (1 R)‐cis‐ were more toxic than esters of the corresponding (1 R)‐trans‐3‐substituted‐2, 2‐dimethylcyclopropanecarboxylic acids; (iii) α‐cyano‐3‐phenoxybenzyl esters were more toxic than the corresponding 3‐phenoxybenzyl esters; (iv) changes in the alcoholic component of some compounds (particularly trans‐isomers of esters of 5‐benzyl‐3‐furylmethanol and esters of α‐cyano‐3‐phenoxybenzyl alcohol) affected a recovery phase in their ED50/time curves more than changes in the acid component; (v) the amount of recovery was positively correlated with molecular polarity. The concentration required to decrease the amplitude of the action potential of giant fibres by 30% in 1 h ranged from 0.26 μM for the most active compound to 100 μM for the least active. There was no clear relationship between neurotoxicity and toxicity to whole insects and little association between neurotoxicity and features of molecular structure. Neurotoxicity was, however, positively correlated with polarity. Giant fibre axons seem unlikely to be critical sites of action of pyrethroids.
The action of (S)‐3‐allyl‐2‐methyl‐4‐oxocyclopent‐2‐enyl (1 R)‐trans‐chrysanthemate, (S)‐bioallethrin, on single neurones in the central nervous system of the leech, Hirudo medicinalis
Authors: Leake Lucy D.
Published: November 2006

Intracellular recordings from identifiable neurones in the leech segmental ganglion in high (20 mM) magnesium Ringer solution showed that (S)‐3‐allyl‐2‐methyl‐4‐oxocyclopent‐2‐enyl (1 R)‐trans‐chrysanthemate, (S)‐bioallethrin, induced three phases of activity: (1) hyperexcitability; (2) repeated depolarisations accompanied by trains of action potentials; and (3) block of action potentials. A linear relation between log (time to onset) of both depolarisations and block and the log (applied dose) was observed over the range 3.44 × 10−7–1.10 × 10−3M. (S)‐Bioallethrin was toxic to leeches at similar concentrations to those effective on isolated ganglia. The possible role of repeated depolarisations in the poisoning process is discussed.
Eradication of apple powdery mildew (Podosphaera leucotricha) with dormant‐season sprays of surface‐active agents
Authors: Hislop Eric C. , Clifford Derek R. , Holgate Margaret E. , Gendle Peter
Published: November 2006

Of twenty non‐ionic surfactant formulations tested in 1974–75 several were successful as eradicants of overwintering apple mildew as were two ionic materials. The incidence of Nectria canker was increased by sprays applied in October but less so by the same materials applied in January or February when phytoxicity measured in terms of fruit yield was also less. PP 222, a non‐ionic surfactant introduced in 1975, proved to be an efficient eradicant of mildew in 1976. Although the yield of fruit from most sprayed trees was greater than from controls, the best mildew eradicants did not produce greatest yields in the same year, perhaps indicating adverse effects of treatments on the trees. However, significantly better yields of fruit obtained in the year following the dormant season eradication of primary mildew, suggest long term beneficial effects of these treatments.
Distribution and metabolic fate of [14C]‐daminozide injected into silver maple and american sycamore seedlings
Authors: Domir Subhash C. , Brown Galen K.
Published: November 2006

The distribution and metabolic fate of [14C]‐daminozide in silver maple and American sycamore seedlings were studied by use of autoradiography, ion‐exchange chromatography, thin‐layer chromatography (t.l.c.), and liquid scintillation spectrometry. Within one day after treatment with [14C]‐daminozide, radioactivity was detected in all parts of the plant. The 14C concentrated in meristematic regions of the leaves. Ion‐exchange and thin‐layer chromatographic analyses of the 50% methanol extracts indicated that no detectable metabolites of daminozide were formed in any of the plant parts but approximately 20% of the applied 14C, most of it in the stem tissue, was not extractable by aqueous methanol.
Inhibition of the hill reaction of isolated chloroplasts by herbicidal phenylureas
Authors: Dicks John W.
Published: November 2006

I50 values have been determined for inhibition of the Hill reaction of lettuce chloroplasts by thirteen phenylurea herbicides, all of which are potent inhibitors. The compounds fall into two groups on the basis of the relationship between pI50 and log (water solubility).
A rapid analytical method for the detection of hexachlorobenzene contamination in agricultural chemicals
Authors: Baker Harvey J. , Courtney Graham F.
Published: November 2006

A rapid screening method was developed to detect possible low level (0.1 mg kg−1) hexachlorobenzene contamination in agricultural chemicals utilising a unique thinlayer chromatographic separation followed by gas‐liquid chromatographic detection.
The algaecidal activity of some substituted 1,3‐diphenylureas, 1‐phenyl‐3‐(2‐pyridyl)ureas and the corresponding thioureas
Authors: Goulding Kenneth H. , Badami Nasi V. , Cremlyn Richard J. W.
Published: November 2006

Twelve ureas and thioureas with 1,3‐diphenyl‐ and 1‐phenyl‐3‐(2‐pyridyl) were tested as potential herbicides in a simple screen against two species of algae Chlorella fusca and Anabaena variabilis. Several were shown to inhibit growth at 100 mg litre−1 but only 1‐[2,4‐bis(azidosulphonyl)phenyl]‐3‐(2‐pyridyl)urea and 1,3‐bis(4‐isopropyl‐ idenehydrazinosulphonylphenyl)thiourea showed any activity at 1 mg litre−1. This compares with the well‐established urea herbicide diuron which, in identical tests, gives similar inhibition of growth at concentrations as low as 0.01 mg litre−1.
The effect of diflubenzuron upon larvae of the geometrid Boarmia (Ascotis) selenaria on avocado leaves
Authors: Ascher K. R. Simon , Wysoki Manes , Nemny Nadia E. , Gur‐Telzak Leah
Published: November 2006

Small (70 mg) Boarmia selenaria larvae fed for 4 days on avocado leaves or alfalfa dipped in aqueous diflubenzuron suspensions suffered from severe developmental disturbances. Similar results were obtained with leaves sprayed in an avocado orchard, with which, in addition, the considerable persistence of diflubenzuron under field conditions could be demonstrated. The substance was also active by topical application against large (500–600 mg) B. selenaria larvae, whereas by contact it was only moderately toxic. Some other non‐conventional control agents, viz., the antifeedant AC‐24055 and several juvenile hormone analogues, were of medium and negligible activity, respectively, against this insect.
Procedures and potentialities in sugar beet production
Authors: Hull Raymond
Published: November 2006

Cultivation procedures for the sugar beet crop continue to change considerably in England. The average contract per grower has increased from 3.4 in 1936 to 8.2 ha in 1973. Within the last decade the use of genetic monogerm seed has extended to 65% of the area sown, and pelleted seed to 90%. Seed spacing has doubled and the hand work needed to establish the crop drastically decreased. Much of the crop is now sown in March, instead of April or even May. The average yield of sugar has increased since 1936 from less than 3.6 to over 6 t ha−1. These changes have been associated with routine usage of fungicide and insecticide on seed and chemical weed control on 90% of the crop in recent years; insecticide, mainly organophosphorus, has been used to control aphids and virus on 36 000 to 125 000 ha of crop annually on the basis of spray warnings; sporadic pesticide control has been used against an abundance of seedling, leaf‐ and root‐eating pests and fungi. The changes in cultural practices have been paralleled by changes in the relative importance of the various pests and diseases—for instance, wide seed spacing and the use of herbicide have intensified seedling pest problems. The extent to which crop losses from weeds, pests and diseases have been assessed as a basis for recommendations for control is discussed, as well as the economics of control by pesticides.
The effects of diflubenzuron on the growth of insect cuticle
Authors: Ker Robert F.
Published: November 2006

Cuticle consists of chitin microfibrils embedded in a matrix composed largely of hydrated proteins. The effect of diflubenzuron, an inhibitor of chitin synthetase, on the deposition of both these components is reviewed. The polymerisation reaction is but one step in the pathway leading to chitin microfibrils. Possibly interactions to other steps in the pathway serve to enhance the consequences of the inhibition. Such enhancement could help to explain the abrupt changes in the rate of chitin synthesis that can be observed as diflubenzuron is cleared from epidermal cells. Cuticle proteins differ widely in their ability to form a stable layer when chitin is largely absent. In the most stable regions, diflubenzuron has no effect on the amount or nature of the proteins deposited. In contrast, there are many regions where the deposition of solid cuticle is stopped, presumably because the proteins involved cannot form a coherent layer. Intermediate degrees of stability are found. There is an association between the regions of stability and those of high sclerotisation; though sclerotisation often takes place long after deposition. Even when the protein layer is fairly stable it may not be deposited in a regular manner. This statement is illustrated by electron micrographs of cuticle from the hind tibiae of adult locusts. These micrographs also show that diflubenzuron can affect epidermal cells. In normal cells the plaques are in contact with the newly secreted cuticle; they are still present but this contact is not maintained after treatment with diflubenzuron.
The prospects of pest control by disruption of arthropod development
Authors: Busvine James R.
Published: November 2006

Disruption of arthropod development is considered under the action of juvenoids (synthetic analogues of juvenile hormone), ecdysones (a class of compounds interacting with the hormone), diflubenzuron and its analogues and, finally, compounds with an anti‐hormone action. The compound's action is classified empirically by the symptoms produced in mosquito larvae.
Photodecomposition of piperazine in water by ‘sunlight’ ultraviolet radiation
Authors: Rouchaud Jean , Moons Chantal , Decallonne Jacques R. , Meyer Joseph A.
Published: November 2006

A solution of piperazine in water was photochemically oxidised by the dissolved oxygen when irradiated with ‘sunlight’ ultraviolet radiation obtained with a Hanau Q‐300 lamp, or with RUL‐300 nm lamps. Sensitisers (riboflavin, acetone and benzophenone) did not increase the rate of the oxidation induced by the RUL‐300 nm lamps; however, they (especially riboflavin) accelerated the oxidation induced by the Hanau Q‐300 lamp. A large number of products were observed in the sensitised oxidation but they were not analysed further. The irradiation mixture of the non‐sensitised photo‐oxidation, when 65% of the initial piperazine had been transformed, contained piperazine (35%), glycine (approximately 25%) and three unidentified compounds in equal amounts (approximately 13% each); the same products were obtained with both irradiation systems. The photo‐oxidation of piperazine, a metabolite of the fungicide triforine, 1,4‐bis(2,2,2‐trichloro‐l‐formamidoethyl)piperaerazine, could thus be a way for the latter's biodegradation at a surface, or in plant tissues, this biodegradation having already been observed.
Identification of the photochemical decomposition product of chlorothalonil by 13C n.m.r. spectroscopy
Authors: Loeffler R. S. Thomas
Published: November 2006

The light‐induced decomposition of chlorothalonil (2,4,5,6‐tetrachloroisophthalonitrile) in benzene and toluene was found to give rise to one and three products respectively. These were shown by gas chromatography‐mass spectrometry to be trichlorodicyanobiphenyls and the benzene adduct was fully identified by 13C n.m.r. spectroscopy as 2,4‐dicyano‐3,5,6‐trichlorobiphenyl.
A multiresidue analytical method for determining organochlorine, organophosphorus, dinitrophenyl and carbamate pesticides in apples
Authors: Johansson Carl E.
Published: November 2006

A multiresidue analytical method for the simultaneous extraction of organochlorine, organophosphorus, dinitrophenyl and carbamate pesticides from apples is presented. Extraction is performed with a mixture of toluene and hexane. After clean‐up on a Florisil column, and in some cases conversion to derivatives, quantitative determination is performed by electron‐capture gas chromatography. Qualitative verification is performed by thin‐layer chromatography or gas chromatography‐mass spectrometry.
The degradation of methazole in soil. I. Effects of soil type, soil temperature and soil moisture content
Authors: Walker Allan
Published: November 2006

[14C]‐Labelled methazole was incubated in six soils at 25°C and with soil moisture at field capacity. Under these conditions, methazole was unstable, the concentration declined following first‐order kinetics with half‐life values in the soils ranging from 2.3 to 5.0 days. The main degradation product was 1‐(3,4‐dichlorophenyl)‐3‐methylurea (DCPMU) which was more stable than the parent compound. After about 160 days, DCPMU accounted for 30 to 45% of the initial methazole concentration. Degradation of methazole and DCPMU was affected by soil temperature and moisture content. With methazole, half‐lives in one soil at field capacity moisture content and temperatures of 25, 15 and 5°C were 3.5, 8.7 and 31.1 days respectively. The half‐life at 25°C was increased to 5.0 days at 50% of field capacity and 9.6 days at 25% of field capacity. A proportion of the initial radioactivity added to the soil could not be extracted and this proportion increased with time. After 160 days this unextractable radioactivity accounted for up to 70% of the amount applied.
The metabolism of cis‐2,5‐dimethylpyrrolidine‐1‐carboxanilide in rodents
Authors: Mitchell Stephen C. , Waring Rosemary H.
Published: November 2006

The metabolism of cis‐2,5‐dimethylpyrrolidine‐1‐carboxanilide was studied in rats, rabbits, guinea‐pigs and mice. The major metabolite in all species was cis‐4′‐hydroxy‐2,5‐dimethylpyrrolidine‐1‐carboxanilide, both free and as glucuronide and sulphate conjugates. About 95% of the compound was absorbed from the gut; over a 3‐day period, about 50% of the administered dose was excreted in urine and about 27% in faeces.
Pest control for cotton production: Present practice and trends for the future
Authors: Johnstone Donald R.
Published: November 2006

Cotton—the world's major fibre crop—is perhaps unique in the broad nature of the insect attack to which it is subjected, and the control of cotton insect pests remains an unabated challenge. In attempting a worldwide review of pest control practices in cotton production it is the diversity of all aspects of the problem which is immediately apparent. A variety of pest control solutions has evolved. This paper attempts to generalise the types of solution and at the same time point out how regional differences and the degree of capitalisation and management control have influenced the chosen approach.
The control of Plasmopara viticola with the 1:1 complex of zineb with 2‐(2‐aminoethylamino)ethanol and the potential effect of the use of this complex on ethylenethiourea residues
Authors: Clifford David P. , Bruyns‐Haylett John P.
Published: November 2006

Zineb 1:1 complex with 2‐(2‐aminoethylamino)ethanol was shown to be more active than zineb in glasshouse and field trials against Plasmopara viticola. The effects of this increase in efficacy on the potential reduction of ethylenethiourea residues are discussed.
Photolysis, metabolism and other factors influencing the performance of triadimefon as a powdery mildew fungicide
Authors: Clark Terence , Clifford Derek R. , Deas Adrian H. B. , Gendle Peter , Watkins David A. M.
Published: November 2006

Triadimefon, 1‐(4‐chlorophenoxy)‐3,3‐dimethyl‐1‐( 1,2,4‐triazol‐1‐yl)butanone, applied at low dosage rates to leaves of marrow, apple or barley plants gave effective control of the appropriate powdery mildew fungi. The compound appeared to be systemic and to have considerable vapour‐phase activity. In marrow plants, up to 56% of triadimefon was metabolised to a mixture of two corresponding diastereoisomeric secondary alcohols. The mixture was identical with that obtained by chemical reduction of triadimefon. This mixture was also a very effective systemic fungicide and active in the vapour‐phase. Triadimefon was also reduced when incubated with Aspergillus niger but this was important only in shake culture. In replacement culture experiments, mycelial mats of this fungus converted the compound into a different metabolite, its isopropyl analogue. This may have resulted from participation of triadimefon in the C‐4 demethylation processes involved in fungal biosynthesis of ergosterol. Photolysis caused cleavage of the C‐1 to triazole bond liberating 1,2,4‐triazole, 4‐chlorophenol and 4‐chlorophenyl methyl carbonate, all of which were non‐fungitoxic. The importance of this photolysis in the in‐vivo situation is discussed.
Inhibition of ergosterol biosynthesis by triadimenol in Ustilago avenae
Authors: Buchenauer Heinrich
Published: November 2006

In Ustilago avenae sporidia, following the first doubling period of about 4 h, triadimenol (2 μg ml−1) affected sporidial multiplication more severely than other growth processes; daughter cells failed to separate from the parent sporidia resulting in chains of interconnected cells. Triadimenol incubated with the fungus for 8 h interfered neither with respiration nor with protein and nucleic acid synthesis but after 6 h the toxicant had induced a higher content of free fatty acids. Triadimenol markedly altered, both quantitatively and qualitatively, the sterols in sporidia of U. avenae. Incorporation of [14C]acetate (in the form of sodium acetate) into lipid fractions for a period of 2 h revealed that the toxicant powerfully inhibited the synthesis of the 4‐demethyl sterol fraction (predominantly ergosterol), whilst the 4,4‐dimethyl sterol fraction rapidly accumulated. This was confirmed by g.1.c. analysis of the sterols after 6 and 8 h incubation which showed that the amount of ergosterol, the major sterol in untreated sporidia, was diminished while simultaneously 4,4‐dimethyl, 4‐methyl and 14‐methyl sterols increased. The accumulation of 14‐methyl sterols suggests that triadimenol acts as a potent inhibitor of one of the metabolic steps involved in the demethylation at the 14‐position during ergosterol biosynthesis.
Further studies on the genetics of the carboxylesterase regulatory system involved in resistance to organophosphorus insecticides in Myzus persicae (Sulzer)
Authors: Blackman Roger L. , Devonshire Alan L.
Published: November 2006

Levels of carboxylesterase activity in F1 clones of Myzus persicae, obtained by crossing sexuales from a resistant, high esterase clone with those from a susceptible, low esterase clone, fell into two distinct groups intermediate between the levels of carboxylesterase in the parent clones. When sexuales of F1 clones of the lower of these two intermediate levels of carboxylesterase activity were crossed, segregation ratios in the F2 generation indicated that this lower intermediate activity level (about 0.4 μmol mg−1 h−1). which is about twice the level in susceptible clones, is due to mutation at a single regulatory locus. The results obtained with backcrosses, between sexuales of an F1 clone having the higher intermediate level of carboxylesterase activity and a parent susceptible, low esterase clone, suggest that a second locus may be involved in the expression of higher levels of esterase activity.
Laboratory studies with antifeedants against larvae of Boarmia (Ascotis) selenaria on alfalfa
Authors: Ascher K. R. Simon , Nemny Nadia E. , Wysoki Manes , Gur‐Telzak Leah
Published: November 2006

The antifeedant effect of five organotin compounds (fentin acetate, fentin hydroxide, fentin chloride, cyhexatin and fenbutatin oxide) and of three other compounds known to possess antifeeding activity (guazatine triacetate, 4′‐chloroacetophenone isobutyrylhydrazone and thiram) was investigated by feeding treated alfalfa to larvae of Boarmia selenaria. The three fentins and cyhexatin were highly active at 0.1 g litre−1, the order of activity at this concentration being fentin chloride > fentin hydroxide > fentin acetate ⩾ cyhexatin, whereas the other compounds were practically inactive at either this or a somewhat higher concentration (0.5 g litre−1). Guazatine triacetate had a concentration‐independent antifeedant effect at much higher concentrations (5–20 g litre−1).
Contact activity of synthetic pyrethroids against adult grass grub, Costelytra zealandica (white)
Authors: Henzell Ronald F. , Lauren Denis R.
Published: November 2006

The field life for contact activity of cypermethrin and permethrin, applied to pasture, was similar for all of five application rates between 0.25 and 1.5 kg ha−1. Laboratory bioassays with grass grub beetles, Costelytra zealandica (White), showed that the insecticides lost their activity after about 4–9 days on pasture. Microencapsulation significantly increased the active field life of permethrin.
Quantitative structure‐activity relationships of pyrethroid insecticides
Authors: Ford Martyn G.
Published: November 2006

The structure‐activity relationships of two congeneric series of pyrethroid insecticides, the methylbenzyl (1RS)‐cis,trans‐chrysanthemates tested against Musca domestica (houseflies) and Phaedon cochleariae (mustard beetles), and the (E)‐4‐aryl‐3‐chlorobut‐2‐enyl chrysanthemates and their corresponding 2,2,3,3‐tetramethylcyclo‐propanecarboxylates tested against M. domestica only, have been examined using multiple regression analyses and substituent constants. With M. domestica, different optimum partition values (π) were indicated for knockdown and toxicity; with P. cochleariae, an optimum π value for toxicity, similar to that for M. domestica, was obtained 24 h after application, but at later times the more lipophilic compounds were more effective. For the methylbenzyl chrysanthemates, a steric constraint associated with 3,5‐dimethyl substitution reduced toxicity approximately five‐fold. The influence on toxicity of geometrical isomerism and electronic effects are briefly discussed. Differences between the required polarities for knockdown and toxicity are attributed to variations in the binding affinities of pyrethroid molecules at the sites of action.
Neurophysiological studies of the effects of permethrin upon pyrethroid resistant (kdr) and susceptible strains of dipteran larvae
Authors: Osborne Michael P. , Hart Richard J.
Published: November 2006

Permethrin at concentrations as high as 10−6 had no detectable effect upon neuromuscular transmission at 20‐21°C in the body‐wall muscles of susceptible larvae of Lucilia sericata and susceptible and resistant (kdr) strains of larvae of Musca domestica. At the higher concentrations of 5 × 10−6M, muscle cells in all strains and species of larva were slowly depolarised, resulting in failure of neuromuscular transmission when the level of depolarisation corresponded with the peak height of the postsynaptic potentials. Multiple postsynaptic potentials were sometimes obtained in response to a single electrical stimulus to the motor axon. Neither of these effects is considered to result from interference with release of the neurotransmitter or its binding to the postsynaptic receptors. Spontaneous activity in sensory nerve fibres from susceptible larvae was increased followed by intermittent bursting and block at concentrations of permethrin as low as 10−9M at 20‐21°C and 10−10 at 26°C. Resistant larvae of M. domestica were 1000 times less sensitive, needing concentrations of permethrin as high as 10−6M at 20‐21°C and 10−7M at 26°C to affect sensory discharge. The results are discussed in relationship to the cause of knockdown by pyrethroid insecticides and to possible changes in the nervous system which may be brought about by the kdr resistance factor.
Toxicodynamics of insecticidal action: An introduction
Authors: Welling Wim
Published: November 2006

As an introduction to insecticide toxicodynamics, a description is given of the elementary processes with their interactions that are essential to an understanding of the dynamic behaviour; these include penetration, binding, biochemical conversions and reactions with the target. Points of ignorance or controversy are emphasised. method is discussed for integrating existing knowledge quantitatively by using mathematical models.
Uptake of iprodione and control of diseases on potato stems
Authors: Cayley George R. , Hide Geoffrey A.
Published: November 2006

When applied to the roots of potato plants growing in different soils iprodione became systemic in the plants. Although iprodione was adsorbed on the soils tested, sufficient fungicide was present in potato stems to prevent infection by Phoma exigua var. foveata on all plants except those grown in peat soils. The amount of fungicide present in the aerial parts of the plant was related to the soil/water distribution coefficients. Application of iprodione to the sprouts of seed potato tubers prior to planting decreased the incidence and severity of infection by Rhizoctonia solani (stem canker) and Polyscytalum pustulans on stem bases.
Pesticide volatilisation rates: A new measurement of the vapour pressure of pentachlorophenol at room temperature
Authors: Dobbs Anthony J. , Grant Colin
Published: November 2006

The rates of volatilisation of pentachlorophenol, gamma‐HCH and HEOD have been measured under the same conditions. The rates found indicate that the vapour pressure of pentachlorophenol at ambient temperatures is ∽ 10−6 mmHg, significantly lower than the widely quoted value ∽ 10−1 mmHg. This lower value accounts for the behaviour of pentachlorophenol better than the existing value, which was obtained by extrapolation of the results of high temperature experiments. It is suggested that the direct measurement of relative loss rates is a simpler method of measuring volatile loss than the measurement of vapour pressure and that the method may prove a useful alternative to vapour pressure measurements in the assessment of the environmental effects of chemicals, particularly for compounds of moderate volatility.
Studies on low‐volume application of plant growth substances; Part 1: Ethylene production, induced by 1‐naphthylacetic acid, as a means of evaluating spray parameters
Authors: Crabtree Garvin D. , Bukovac Martin J.
Published: November 2006

The evolution of ethylene, induced by 1‐naphthylacetic acid (NAA), was studied as a means of evaluating spray parameters using cowpea [Vigna sinensis (Torner) Savi] under defined conditions as a test system. The dose‐response curve was linear over the range of 1.4‐14 μg per leaf. The marked production of ethylene following treatment with an active auxin, 2,4‐D (2,4‐dichlorophenoxyacetic acid), and the absence of its production following treatment with an inactive analogue (3,5‐dichlorophenoxyacetic acid), established that ethylene production was hormonally induced. The effect of application volumes of 10‐100 μ1 and of droplet sizes of 1‐10 μ1 were evaluated using a constant dose (5 μg NAA per leaf); NAA was more effective when delivered to the leaf in the larger volumes but in the smaller droplet sizes.
Quantitative structure—activity relationships for nicotinanilide molluscicides
Authors: Dunlop Robert W. , Duncan John , Ayrey Geoffrey
Published: November 2006

Structure‐activity correlations for the toxicity of nicotinanilides to Biomphalaria glabrata have been studied in terms of partitioning, charge transfer and steric properties. Partition coefficients or πNA values (substituent constants for nicotinanilides, reflecting the influence on the partition coefficient of a substituent on the parent molecule) have been shown to contain a significant electronic component and to be related to chromatographically determined RM values (derived from a relationship between the partition coefficient and RF value for liquid‐liquid chromatographic systems). There was no overall correlation between LC50 values and partitioning, electronic or steric effects. However, for ten 4′‐substituted nicotinanilides, the LC50 values correlated significantly with partitioning, an increase in lipophilic character leading to an increase in biological activity. The greater activity of the unsubstituted parent compound could not be explained by purely advantageous steric effects but the 4′‐position may be an important metabolic site. Use of compounds labelled with deuterium failed to clarify this point because no isotope effects were observed.
Distribution of the radioactivity in sugar beet plants treated with [14C]aldicarb
Authors: Rouchaud Jean , Moons Chantal , Meyer Joseph A.
Published: November 2006

Sugar beet plants were grown in the field, after in‐furrow application of [14C]aldicarb (3 kg of aldicarb ha−1) at planting. Some plants (the growing plants) were harvested 99 days after sowing and the rest (the ripe plants) 196 days after sowing. The percentages of the weights of [14C]aldicarb equivalents (the total aldicarb plus aldicarb sulphoxide and sulphone, plus all the other metabolites of [14C]aldicarb which contain 14C, expressed as aldicarb equivalents) incorporated into the beet plants, relative to the weight applied to the soil, were 2.8 and 1.8, respectively for the growing and ripe plants. The concentrations of [14C]aldicarb equivalents (mg kg−1 fresh weight) in the growing and ripe plants, respectively were: blades of the external leaves, 3.16 and 0.93; blades of the internal leaves, 0.63 and 0.68; petioles of the external leaves, 0.51 and 0.26; petioles of the internal leaves, 0.15 and 0.05; crowns, 0.14 and 0.15; roots, 0.16 and 0.13. The proportions of the extractable aldicarb plus aldicarb sulphoxide and aldicarb sulphone determined by gas‐liquid chromatography (expressed as aldicarb equivalents) relative to [14C]aldicarb equivalents, in the external and internal leaf blades of the growing beets, were 56 and 60%, respectively; these values declined to 25 and 19%, respectively in the ripe plants. The proportion was 21 % or less in all other parts of the growing and ripe plants.
β‐cyclodextrin inclusion complexes of pyrethroids
Authors: Yamamoto Izuru , Katsuda Yoshio
Published: November 2006

Pyrethroids are more stable to practical conditions when included in β‐cyclodextrin, particularly because photodecomposition is reduced. Though inclusion sometimes decreases the contact insecticidal activity, the innate activity is regenerated under conditions which release the free pyrethroids. Stabilised dust and wettable powder formulations of natural pyrethrins show promising insecticidal effects to certain pest insects.
Fluorinated analogues of chrysanthemic acid
Authors: Bentley Philip D. , Cheetham Rex , Huff Roger K. , Pascoe Roger , Sayle John D.
Published: November 2006

Novel halogenated chrysanthemic acid analogues have been prepared and the interesting properties of their esters are described. Among this group are the most active insecticides yet reported.
The uptake of metabolites of permethrin by plants grown in soil treated with [14C]permethrin
Authors: Leahey John P. , Carpenter Paul K.
Published: November 2006

Sugar beet, wheat, lettuce and cotton were grown in soil treated with [14C]permethrin, the crops being sown at intervals of 30, 60 and 120 days after treatment of the soil. The uptake of radioactive residues into these crops was measured. Low radioactive residues (up to 0.86 μg g−1) were detected in the mature plants sown 30 days after soil treatment, and this uptake declined significantly as the interval between soil treatment and sowing increased. Metabolites derived from the acid moiety of the permethrin molecule were shown to constitute the greater part of the residue transferring from the soil to the crops. (1RS)‐cis‐ and (1RS)‐trans‐3‐(2,2‐dichlorovinyl)‐ 2,2‐dimethylcyclopropanecarboxylic acid and 3‐(2,2‐dichlorovinyl)‐1‐methylcyclopropane‐1,2‐dicarboxylic acid were identified as the major acidic metabolites. The latter compound is a metabolite of permethrin which has not previously been identified in soil or plants.
The uptake, translocation and metabolism of epronaz in selected species
Authors: Mellis Jill M. , Kirkwood Ralph C.
Published: November 2006

The absorption, translocation and metabolism of the selective pre‐ or early post‐ emergence herbicide epronaz (N‐ethyl‐N‐propyl‐3‐propylsulphonyl‐1,2,4‐triazole‐1‐carboxamide) were investigated using selected crop and weed species. The pattern of tolerance to epronaz of both germinating seeds and 10‐day‐old plants grown in nutrient solution, was found to be soybean (Glycine max L.) > maize (Zea mays L.) > cotton (Gossypium hirsutum L.) > rice (Oryza sativa L.) > barnyard grass [Echinochloa crus‐galli (L.) Beauv.]. In all species, absorption and translocation of 14C from a nutrient solution containing [14C]epronaz (0.02 μCi ml−1) increased with time. Autoradiographic and liquid scintillation analysis indicated the presence of radioactivity in the apical regions of all species after 4 h. Interspecies variation in uptake and distribution did not appear to be a major factor explaining selectivity, although the resistance of cotton may be partly due to compartmentalisation of 14C in the lysigenous glands in stem and leaves. Analysis of extracts from plants treated with [14C]epronaz indicated the presence of epronaz, its major degradation product [3‐propylsulphonyl‐l,2,4‐triazole (BTS 28 768)] and certain unknown radio‐labelled compounds. The major metabolite (Unknown I) was believed to be a conjugate of certain plant components with either epronaz or BTS 28 768. The rate of formation of Unknown I corresponded to the relative resistance and susceptibility to epronaz of soybean, rice and barnyardgrass. The level of the herbicide remained much higher in cotton than in the other species, possibly reflecting compartmentalisation and inactivation of epronaz in the lysigenous glands. For maize, high levels of uptake, exudation and degradation in the nutrient solution were recorded.
Measured and simulated behaviour of aldicarb and its oxidation products in fallow soils
Authors: Bromilow Richard H. , Leistra Minze
Published: November 2006

Aldicarb and its oxidation product aldoxycarb (aldicarb sulphone) were applied separately to columns of fallow, sandy loam soils under field conditions. The breakdown and movement of these compounds were monitored, as was the behaviour of aldicarb sulphoxide and aldoxycarb formed by oxidation of the applied aldicarb. The behaviour of these compounds was simulated by a computer model using laboratory data for adsorption and rates of degradation in soil. The model simulated the observed behaviour reasonably well, although redistribution of chemicals was often more rapid than predicted. Production of aldoxycarb from the sulphoxide was less in the field than was expected from the laboratory incubations. Accumulation of chemicals near the soil surface in dry periods was overestimated, indicating that the processes occurring under these conditions are not well described by the model. About 4 months after application, only aldoxycarb, in small amounts, remained in the soils.
Automatic night‐time spraying with droplets of small size against Helicoverpa armigera (Hb.) adults on cotton
Authors: Hugh Rendell C.
Published: November 2006

A description is given of the design and construction of an automated portable sprayer and its effect when releasing small amounts of a 5% permethrin (cis: trans ratio 40:60) ultra‐low‐volume formulation over cotton at night from a fixed position. The infestation of Helicoverpa armigera (Hb.) on the treated plot is compared with that on control plots which were sprayed uniformly with the same amount of insecticide per unit area once a week, or with dimethoate. Using droplets with a volume‐median‐diameter (v.m.d.) of 40‐50 μm, air movements gave a non‐uniform deposition of insecticide around the fixed sprayer position, and an observable effect up to 20 m downwind. When compared with the controls, the plot sprayed nightly had very high oviposition on plants near to the sprayer and an unusually large number of eggs laid in groups. The overall level of insect control was best on the plot sprayed weekly and uniformly with the permethrin formulation, using larger (80‐μm v.m.d.) droplets.
Fate of [14C]daminozide and [14C]maleic hydrazide in American elm (Ulmus americana L.)
Authors: Domir Subhash C.
Published: November 2006

Radiolabelled daminozide and maleic hydrazide (MH) were injected into American elm seedlings, kept in nutrient solution, to determine their translocation pattern and metabolic fate. Both compounds were rapidly translocated to all parts of the plant. After 21 days, 13% of the applied 14C was exuded into the nutrient solution from the roots of the plants treated with MH. Using gel‐filtration and thin‐layer chromatographic techniques, it was determined that daminozide did not form any metabolite, and that MH was converted into a MH‐sugar complex. A significant amount of 14C was unextractable from the plant tissue.