摘要:

AbstractA technique is described for the automatic recording of the uptake of pesticides and related compounds by viable, small organisms suspended in aqueous solution. The relation of time to uptake thus determined allows the study of the kinetics and the characterisation of the uptake processes.The technique is based on a recycling of the incubation vessel fluid, obtained by a simple filtration process, through the flow cell of a spectrophotometer. The rate of uptake of compounds, which need to have sufficient absorption in the visible and u.v. region, is followed spectrophotometrically by repetitive measurement of spectra or of absorbance values at a single wavelength. Uptake processes are studied under controlled conditions of temperature and atmosphere. The method has proved to be applicable to yeast cells, fungal spores, nematodes, insect eggs and algae, so that it can be used to good advantage in pesticide research.However, the technique is not suitable for very small organisms such as bacteria and for easily deformable cells, e.g. erythrocytes.The utility of the method has been demonstrated in the uptake of 2‐chloro‐6‐phenylpyridine by nematodal larvae (Anguina tritici) which sorb the compound reversibly, and in the uptake of 4,5‐dichloro‐2‐nitrobenzonitrile by fungal spores (Fusarium culmorum) which is converted into the corresponding amino compound. These examples illustrate that the technique is very useful for the study of uptake processes which can be interpreted in terms of accumulation or convers

ISSN:0031-613X    

DOI:10.1002/ps.2780030102

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractAn analytical method and results are given for the determination of total mercury residues in: Brussels sprouts; cabbages, heading broccoli and kale; potatoes; apples; carrots; imported tomatoes; tinned tomatoes, tomato juices and purees; rice; sugar. Residues in the 146 samples were in the range<0.001 to 0.010 parts/million, the mean being 0.0027 parts/million.

ISSN:0031-613X    

DOI:10.1002/ps.2780030103

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThin‐layer chromatography was used to assess semi‐quantitively the persistence of six organophosphorus insecticides in hen‐house litter. Malathion disappeared within 4 h of application. Carbofenthion was the most persistent. Four weeks after treatment the proportions of the applied doses extracted from the litter were: carbofenthion 46%, phorate 21%, diazinon 13%, coumaphos 7% and fenitrothi

ISSN:0031-613X    

DOI:10.1002/ps.2780030104

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe insecticidal activities to houseflies and to mustard beetles of the 19 methylbenzyl (±)‐cis‐trans‐chrysanthemates were measured to establish the patterns of substitution that produce the greatest toxicities to these insects. The two species of insect differ in their responses to the various compounds in the series. The most active compounds to houseflies and mustard beetles are, respectively, 2,4,6‐and 2,3,6‐trimethylbenzyl (±)‐cis‐trans

ISSN:0031-613X    

DOI:10.1002/ps.2780030105

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractA method is described for the determination of residues of fenazaflor (I), its hydrolysis product 5,6‐dichloro‐2‐trifluoromethylbenzimidazole (II) and the metabolite 5,6‐dichloro‐4‐hydroxy‐2‐trifluoromethylbenzimidazole (III) in apples and pears. These chemicals may be present in the crop as a result of the application of the acaricide fenazaflor, formulated as a wettable powder and known by the trade name ‘Lovozal’.Total residues of I and II are determined as II, and III is determined after methylation, both by GLC with electron capture detection. The limit of detection for each compound is 0.02parts/million (based on a 50 g sample weight). Recoveries are over 80%.Using apples sprayed with radio‐labelled fenazaflor it was shown that approximately 20% of the total radioactivity present in the fruit was not extracted by the routine method. Further investigation showed much of this to be present as trifluoroacetic acid in a tightly bound form.No problems were encountered with interference from a number of commonly us

ISSN:0031-613X    

DOI:10.1002/ps.2780030106

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe occasional need for separation of residues of fenazaflor and its hydrolysis product, instead of determination of the total residue by the routine method, is satisfied by partition of the extract between hexane and acidified aqueous methanol. Both residues are subsequently determined as the hydrolysis product by GLC with electron capture detection, after hydrolysis of fenazaflor.

ISSN:0031-613X    

DOI:10.1002/ps.2780030107

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe outcome of our earlier work suggested that the transport of contact insecticides into insects does not involve the haemolymph, but that the chemical probably reaches the internal organs by migratinginand/oroverintegumental tissue. This applies to various insects having quite different integumental organisation, and to various groups of insecticides differing widely in physical and chemical characteristics.The present work has shown that carbamates (1‐alkylthioacetaldoxime carbamates) with high water solubility are no exception. The permeability of the body wall of the housefly for the methyl homologue (methomyl) which is the most water‐soluble of the series, although relatively high, is not high enough to account for the toxicity of the compound if it followed the haemolymph route. Methomyl when injected with water instead of an organic solvent was also found to be less toxic than the equivalent amount topically applied.Lateral migration in the integument could be demonstrated with all the carbamates tested and dissimilarities in rates were apparent. Methomyl migrated the most rapidly and the cyanomethylene homologue the most slowly. Differences in mobility may be partly responsible for inequality in toxic effect, but it is thought that metabolic detoxication is of over‐riding impor

ISSN:0031-613X    

DOI:10.1002/ps.2780030108

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractExtracts of pyrethrum flowers were obtained by treatment with various aqueous and organic solvents. These were tested for immediate and delayed hypersensitivity reactions in guinea pigs previously sensitised to pyrethrum by single subcutaneous injection of the ground flowers suspended in Freund's complete adjuvant. Strong reactions were elicited by various aqueous extracts of the flowers; the allergens are of high molecular weight, being non‐dialysable. A hexane extract (similar to pyrethrum oleoresin) produced a moderate reaction, but a commercially refined pyrethrum extract proved negative.An extract of the spent flowers with methylene chloride showed irritant effects in unsensitised guinea pig

ISSN:0031-613X    

DOI:10.1002/ps.2780030109

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractDetails are given for the construction and operation of apparatus for laboratory fumigations with methyl bromide using controlled concentrations and continuous flow. The apparatus is useful for obtaining accurate dosage response data for soil organisms.

ISSN:0031-613X    

DOI:10.1002/ps.2780030110

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractProcedures were developed for the rapid sampling of deep soil atmospheres in the field and analysing them by gas chromatography. The methods described here have been used in studies on the diffusion of methyl bromide in relation to the control ofArmillaria mellea.

ISSN:0031-613X    

DOI:10.1002/ps.2780030111

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY