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The toxicity of insecticides to larvae of the codling moth, Cydia pomonella (L.). I.—Intrinsic toxicity and persistence

Published online by Cambridge University Press:  10 July 2009

M. Gratwick
Affiliation:
East Mailing Research Station, Maidstone, Kent
J. M. Sillibourne
Affiliation:
East Mailing Research Station, Maidstone, Kent
R. P. Tew
Affiliation:
East Mailing Research Station, Maidstone, Kent

Extract

The deposits found on apples at various times after application of 11 insecticides were determined by chemical analysis of samples from an orchard in south-eastern England sprayed in 1959 and 1960. The results, from samples taken simultaneously, of studies of the effectiveness of these and other chemicals for control of the codling moth, Cydia pomonella (L.), have already been reported.

The period in which 50 per cent, of an initial deposit disappeared in the field (half-life) was calculated from the chemical data and used as a measure of persistence. For comparisons of intrinsic toxicity, the levels of fresh deposits causing 50 per cent, mortality of newly emerged codling-moth larvae (LD50) were determined in the laboratory by chemical and biological tests on apples dipped in a range of concentrations of commercial formulations. The LD50's, in μg./cm.2, were less than 0·025 for carbophenothion, parathion and diazinon, between 0·025 and 0·05 for azinphos-methyl and -ethyl, between 0·05 and 0·10 for malathion, DDT and carbaryl, between 0·1 and 0·5 for DDD and dimethoate, between 0·5 and 1·5 for lead arsenate and above 1·5 for phenkapton.

Chemicals with an LD50 exceeding about 0·1 μg./cm.2 were considered not worth further investigation as codling-moth larvicides. The LD90's of the remainder were found and were taken as the minimum deposits that would have an adequate effect from the standpoint of control (minimum effective levels). From the half-life values, the periods for which the deposits found in the orchard in 1960 should have remained above the minimum effective levels were calculated; these were 24 days for DDT emulsion, 22 for DDT wettable powder, 15 for carbophenothion, 14 for carbaryl, 12 for azinphos-ethyl, 11 for parathion, 7 for malathion and 6 for diazinon. They were in good agreement with the results of the biological tests except in the case of DDT emulsion, the effectiveness of which was unexpectedly short-lived.

Type
Research Paper
Copyright
Copyright © Cambridge University Press 1965

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References

Association of Official Agricultural Chemists (1950). Official methods of analysis.—7th edn., pp. 369371. Washington, D.C., Ass. off. agric. Chem.Google Scholar
Averell, P. R. & Norris, M. V. (1948). Estimation of small amounts of O,O-diethyl O-(p-nitrophenyl) thiophosphate.—Anal. Chem. 20 pp. 753756.CrossRefGoogle Scholar
Gratwick, M. (1964). Laboratory assessment of the toxicity of field-weathered deposits of insecticides to larvae of the codling moth, Cydia pomonella (I,.).—Bull. ent. Res. 55 pp. 3547.CrossRefGoogle Scholar
Norris, M. V., Vail, W. A. & Averell, P. R. (1954). Colorimetric estimation of malathion residues.—J. agric. Fd Chem. 2 pp. 570573.CrossRefGoogle Scholar
Patchett, G. G. (1956). Colorimetric method for the determination of R-1303 in plant materials.—14 pp. Richmond, Calif., Stauffer Chemical Co.Google Scholar
Suter, R., Delley, R. & Meyer, R. (1955). Analysenmethoden einiger neuer Schädlingsbekämpfungsmittel.—Z. anal. Chem. 147 pp. 173184.CrossRefGoogle Scholar
Tew, R. P. & Sillibourne, J. M. (1961). Pesticide residues on fruit. I. Microbioassay of pesticide residues using the vinegar fly, Drosophila melanogaster.—J. Sci. Fd Agric. 12 pp. 618623.CrossRefGoogle Scholar
Tew, R. P. & Sillibourne, J. M. (1962). The persistence of certain acaricides on apple foliage in the field.—49th Rep. E. Malling Res. Sta. 1961 pp. 113116.Google Scholar
Tew, R. P., Sillibourne, J. M. & Silva-Fernandes, A. M. (1961). Pesticide residues on fruit. V. Harvest residues of codling moth insecticides on apples.—J. Sci. Fd Agric. 12 pp. 666674.CrossRefGoogle Scholar
Turrell, F. M. (1946). Tables of surfaces and volumes of spheres and of prolate and oblate spheroids, and spheroidal coefficients.—153 pp. Berkeley, &c., Univ. Calif. Pr.Google Scholar