摘要:

AbstractThe degradation of the wild‐oat herbicide flamprop‐isopropyl, [isopropyl (±)‐N‐benzoyl‐N‐(3‐chloro‐4‐fluorophenyl)alaninate], in four soils has been examined under laboratory conditions with sampling times of up to 45 weeks after treatment. The major degradation product of [14C]flamprop‐isopropyl in all soils at up to 10 weeks after treatment was the carboxylic acid (±)‐N‐benzoyl‐N‐(3‐chloro‐4‐fluorophenyl)alanine. This compound in turn underwent degradation by loss of the benzoyl group and the propionic acid moiety, with evolution of [14C]carbon dioxide to form 3‐chloro‐4‐fluoroaniline (CFA). The CFA was formed slowly in soil and occurred mainly as a bound form. There was evidence to show that the CFA was subsequently converted into other polar products. The time for depletion of 50% of the applied herbicide was approximately 10 weeks in sandy loam and medium loam soils, 11 weeks in a c

ISSN:0031-613X    

DOI:10.1002/ps.2780100102

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe in‐vitro metabolism ofO,O‐diethylS‐(N‐methylcarbamoymethyl) phosphorodithioate in mouse liver was studied. The major route of metabolism was via the mixed‐function oxidases present in the microsomal fraction, which formed the oxygen analogue,O,O‐diethyl hydrogen phosphorothioate and diethyl hydrogen phosphate upon addition of nicotinamide‐adenine dinucleotide phosphate (NADPH). In the absence of NADPH, the carboxylic acid analogue (S‐carboxymethylO,O‐diethyl phosphorodithioate) was isolated only from the microsomal fraction. Addition of glutathione to the 100 000gsupernatant resulted in no metabolism of the parent compound. However, addition of glutathione to the 10 000 g supernatant resulted in the carboxylic acid formed by amidase activity being further metabolised toO,O‐diethyl hydrogen phosphorodithioate by a glutathione

ISSN:0031-613X    

DOI:10.1002/ps.2780100103

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractWater penetrated through isolated leaf cuticles of dwarf orange (Citrus mitisBlanco, ‚Calamondin’︁) as undissociated molecules because both [18O] water (1H218O) and HTO (1H3H16O) permeated at the same rate. HTO penetrated to 3 to 21% of the theoretical equilibrium value (TEV) in an unstirred system within 10 days for astomatous cuticles and 50 to 60% of TEV for stomatous cuticles. The permeability coefficient (k) of HTO through astomatous cuticles at 25°C was 6.8 × 10−7cm s−1. Two highly water‐soluble14C‐labelled compounds, trichloroacetic acid (TCA) and 1,2,4‐triazol‐3‐ylamine [aminotriazole (BSI) or amitrole (ISO)], and two nearly water‐insoluble14C‐labelled compounds, 1‐naphthyl methylcarbamate (carbaryl) and 2,6‐dichloro‐4‐nitroaniline (dicloran), were compared to HTO as a reference standard in permeation studies. All four organic molecules permeated without decomposing. The relativekvalues for TCA, aminotriazole, carbaryl, HTO and dicloran were 0.32, 0.47, 0.71, 1.0, and 1.5 respectively. Although this suggested that the permeation of organic molecules may be inversely related to water solubility, this could not be established with certainty due to large variations in the data. Thekvalues were obtained for 12 other organic compounds through a variety of biological and model membranes or were calculated from the literature. Any relationships betweenkand various molecular characteristics were unclear because a wide variety of cuticle sources and experimental design was used by different investigators working in this area. The calculation ofkis considered essential in all permeability studies so that comparisons

ISSN:0031-613X    

DOI:10.1002/ps.2780100104

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe knockdown and contact killing actions of various pyrethroids were compared usingBlattella germanicaandPeriplaneta americana. A wide range of knockdown activity was found; 5‐benzyl‐3‐furylmethyl (1R)‐cis‐3‐(dihydro‐2‐oxo‐3‐thienylidenemethyl)‐2,2‐dimethylcyclopropanecarboxylate (RU 15525) acted fastest, more rapidly than pyrethrins, againstB. germanicaas well as having a low LD50value. Topical application and direct spray tests showed that (S)‐α‐cyano‐3‐phenoxybenzyl (1R)‐cir‐3‐(2,2‐dibromovinyl)‐2,2‐dimethylcyclopropanecarboxylate (NRDC 161) was more active as a killing agent, by an order of magnitude, than cismethrin, the next most active compound, and also had considerable knockdown activity. Piperonyl butoxide generally had little synergist effect. FemaleP. americanawere over three times more tolerant than males to a range of insecticides applied topically. Residual knockdown action in the WHO resistance test was observed to provide baseline data. There was little overlap in speed of action between pyrethroids and o

ISSN:0031-613X    

DOI:10.1002/ps.2780100105

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe structure‐activity relationships of two congeneric series of pyrethroid insecticides, the methylbenzyl (1RS)‐cis,trans‐chrysanthemates tested againstMusca domestica(houseflies) andPhaedon cochleariae(mustard beetles), and the (E)‐4‐aryl‐3‐chlorobut‐2‐enyl chrysanthemates and their corresponding 2,2,3,3‐tetramethylcyclo‐propanecarboxylates tested againstM. domesticaonly, have been examined using multiple regression analyses and substituent constants. WithM. domestica, different optimum partition values (π) were indicated for knockdown and toxicity; withP. cochleariae, an optimum π value for toxicity, similar to that forM. 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 molec

ISSN:0031-613X    

DOI:10.1002/ps.2780100106

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

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

ISSN:0031-613X    

DOI:10.1002/ps.2780100107

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe uptake and metabolism of triadimefon by mycelia of fungi, sensitive or resistant to triadimefon, were studied. In the mycelia the triadimefon content accumulated to 20‐40‐fold of the external concentration, irrespective of the sensitivity of the fungus. In the course of the metabolism a highly fungitoxic product, triadimenol, was formed. In mycelia of sensitive fungi this transformation was at a high rate whereas it could not be demonstrated or only to a low extent in resistant types. The material produced by the sensitive fungi was effective also against fungi basically resistant to triadimefon. Based on these observations, triadimefon has to be regarded as the precursor of triadimenol. In the species investigated, selectivity may be related mainly to the rate of activation. In higher plants the metabolism of triadimefon showed a similar pattern, but was slower than with fungi. As the transformation into triadimenol (activation) begins thus early in the host tissues, the systemic fungitoxic effect is also influenced by the host plant itself. Regarding the speed of activation differences were found between the four plant species investiga

ISSN:0031-613X    

DOI:10.1002/ps.2780100108

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe action of seven cholinesterase‐inhibiting pesticides [aldicarb, carbaryl, carbofuran, oxamyl, paraoxon (diethyl 4‐nitrophenyl phosphate) parathion and trichloronate], the organochlorine insecticide, gamma‐HCH, and the nematicide potassiumN‐hydroxymethyl‐N‐methyl(dithiocarbamate) (PHMD) on four earthworm species was investigated by laboratory toxicity tests.Eisenia foetidawas the most tolerant species to the pesticides tested. Aldicarb was the most toxic pesticide to this species, causing severe dehydration prior to death or at sublethal concentrations. Aldicarb was also toxic to the other species (Allolobophora caliginosa, A. chloroticaandLumbricus rubellus), while oxamyl, the other oxime carbamate, was not toxic to any of them. Carbaryl and carbofuran at low concentrations were lethal toA. caliginosa, A. chloroticaandL. rubellus, butE. foetidacould tolerate high concentrations without dying, although low concentrations severely affected its ability to work the soil or to disappear from the soil surface. Paraoxon, parathion, trichloronate and gamma‐HCH were moderately toxic with low lethal effect to all species. The ability to work the soil was moderately affected by parathion, trichloronate and gamma‐HCH. PHMD was toxic to all the species. The lethal and non‐lethal effects of the pesticides are discussed in relation to their possible biochemical mode of action in earthworms, and the data are compared with published information

ISSN:0031-613X    

DOI:10.1002/ps.2780100109

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractClover is frequently grown in rotation with cereals in order to increase soil nitrogen. The systemic fungicide triadimefon, widely used against cereal pathogens, is readily taken up from soil by clover and degraded to a single major metabolite. Plant weight and symbiotic nitrogen fixation byRhizobium trijoliiare affected only by concentrations of triadimefon in soil that are much in excess of those likely to be encountered in practice. Triadimefon residues are thus unlikely to affect nitrogen fixation by clover under field conditions.

ISSN:0031-613X    

DOI:10.1002/ps.2780100110

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe rates of disappearance of atrazine, dichlorprop, linuron and propyzamide were measured in two soils incubated at 22°C and 80% water holding capacity. Observations were made at four pH levels in each soil. Atrazine degradation was relatively insensitive to pH; it increased slightly with increasing pH in one soil and decreased in the other. The other compounds all degraded more slowly at low pH in both soils although dichlorprop had essentially disappeared in 14 days under all conditions, so that the effect of pH is not unlikely to be of practical interest. The ratios of the degradation rates of atrazine, linuron, and propyzamide varied with the soil and the pH

ISSN:0031-613X    

DOI:10.1002/ps.2780100111

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY