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An evaluation by bioassay of the persistence of DDT deposits on riverine vegetation in the Northern Guinea Savannah vegetation Zone of Nigeria and observations on the factors influencing the availability of deposits to Glossina palpalis (R.-D.)

Published online by Cambridge University Press:  10 July 2009

D. A. T. Baldry
D. A. T. Baldry
Affiliation:
West African Institute for Trypanosomiasis Research, Kaduna, Northern Nigeria.
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Extract

The persistence of DDT deposits, derived from dilutions of an emulsion concentrate, Arkotine D.25, on the leaves of riverine vegetation in the Northern Guinea Savannah vegetation zone of Nigeria was studied in the laboratory by a bioassay method using teneral females of Glossina palpalis (R.-D.) as test insects. Irrespective of whether sprayed in the dry or wet season, deposits derived from sprays containing 5.0 per cent. DDT produced by the Warley knapsack sprayer were still reasonably toxic one year after spraying. Deposits derived from sprays having a concentration of DDT varying from 1·25 to 5·0 per cent. DDT were equally toxic when young, but those from the lower concentrations were weathered much more rapidly than those from the 5·0 per cent, sprays. Young deposits produced by Warley and Motoblo sprayers were equally toxic, but deposits from the Motoblo deteriorated more rapidly than those of the Warley.

The toxicity of the DDT deposits on leaves varied regularly with the seasons. The various climatic factors that it is thought influenced the variations in toxicity are discussed. Accumulations of wind-blown dust on the leaves during the late dry season and low evaporation rates at the height of the rains appear to be responsible for reduced toxicity at those times; in the early wet season, the occasional violent storm probably washes off the leaves the dust accumulated during the dry season and makes the insecticidal deposits once more available. Heavy rainfall is important in removing the insecticidal deposits from the vegetation, and leaf decay and refoliation are important in reducing the availability of the deposits. The implications of these variations in toxicity and factors that reduce the availability of the deposits are discussed in relation to the eradication of riverine tsetse.

Great differences in the rates of foliage decay and refoliation occur between different riverine plants, and it is suggested that a thorough study of this feature in riverine plants and of resting sites favoured by tsetse flies might reveal information that would enable tsetse to be eradicated by selective spraying of certain plant species only.

Type
Research Paper
Information
Bulletin of Entomological Research , Volume 54 , Issue 3 , November 1963 , pp. 497 - 508
Copyright
Copyright © Cambridge University Press 1963

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References

Anon. (1960). Insecticide resistance and vector control. Tenth report of the expert committee on insecticides.—Tech. Rep. World Hlth Org. no. 191, 98 pp.Google Scholar
Baldry, D. A. T. (in press). Some aspects of the toxicity of DDT emulsion deposits to Glossina palpalis (R.-D.). I. The detection and fate of DDT-poisoned G. palpalis.—Rep. 9th Mtg int. sci. Comm. Tryp. Res., Conakry 1962.Google Scholar
Burnett, G. F. (1962). The susceptibility of tsetse flies to topical applications of insecticides. III. The effects of age and pregnancy on the susceptibility of adults of Glossina morsitans Westw.—Bull. ent. Res. 53 pp. 337–345.CrossRefGoogle Scholar
Davies, J. B. (1958). An attempt to eradicate Glossina palpalis (R.-D.) and G. tachinoides Westw. from riverine vegetation in Benue Province, Northern Nigeria, by spraying with DDT.—Bull. ent. Res. 49 pp. 427–436.CrossRefGoogle Scholar
Gerolt, P. (1963). Influence of relative humidity on the uptake of insecticides from residual films.—Nature, Lond. 197 no. 4868 p. 721.CrossRefGoogle ScholarPubMed
Keay, R. W. J. (1953). An outline of Nigerian Vegetation.—2nd edn., 55 pp. Lagos, Govt. Printer.Google Scholar
Keay, R. W. J. (1960). An example of Northern Guinea zone vegetation in Nigeria.—Nig. For. Inf. Bull. (N.S.) no. 1, 46 pp.Google Scholar
Kernaghan, R. J. [1961]. Some aspects of the insecticidal control of Glossina tachinoides in Northern Nigeria.—Rep. 8th Mtg int. sci. Comm. Tryp. Res. Jos 1960 pp. 285–293.Google Scholar
Kernaghan, R. J. & Johnston, M. R. L. (1962). A method of determining insecticide persistence in tsetse fly control operations.—Bull. Wld Hlth Org. 26 pp. 139–141.Google ScholarPubMed
Kirkby, W. W. & Blasdale, P. (1960). The eradication of Glossina mositans submorsitans Newst. and Glossina tachinoides Westw. in part of a river flood plain in Northern Nigeria by chemical means. Part II.—Bull. ent. Res. 51 pp. 253–264.CrossRefGoogle Scholar
Morris, M. G. (1950). The persistence of toxicity in DDT-impregnated hessian and its use on tsetse traps.—Bull. ent. Res. 41 pp. 259–288.CrossRefGoogle Scholar
Nash, T. A. M. & Page, W. A. (1953). The ecology of Glossina palpalis in Northern Nigeria.—Trans. R. ent. Soc. Lond. 104 pp. 71–169.Google Scholar
van Tiel, N. (1952). On “ Supona ”, a new type of DDT suspension.—Bull. ent. Res. 43 pp. 187–202.CrossRefGoogle Scholar
Ward, J. & Burt, P. E. (1955). The persistence and fate of DDT on foliage. II.—Comparative rates loss of DDT deposits from glass plates and growing leaves.—Bull. ent. Res. 46 pp. 849–868.CrossRefGoogle Scholar