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The potential of natural enemies of the cotton whitefly in Sudan Gezira

Published online by Cambridge University Press:  19 September 2011

Asim A. Abdelrahman
Asim A. Abdelrahman
Affiliation:
Gezira Research Station, Agricultural Research Corporation, Wad Medani, Sudan
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Abstract

The cotton whitefly, Bemisia tabaci (Genn.), is parasitized by four Aphelinid species: Eretmocerus diversiciliatus Silv., E. mundus Merc., Encarsia lutea Masi. and an unidentified Encarsia sp Whitefly adults move from field weeds onto cotton during the period September–November. The application of broad-spectrum insecticides to control other cotton pests early in the season prevents the establishment of the host-stage of B. tabaci needed by the parasitoids within cotton fields during September and October. The rate of parasitism is consequently decelerated to peak in January towards the end of the season. Peak per cent parasitism for treated cotton fields was 36.7 as compared to 76.8 in untreated fields. This has promoted B. tabaci to an all season pest instead of an early and mid-season occasional pest. Alternative control strategies for early season pests are discussed.

Résumé

La mouche blanche du cotonnier, Bemisia tabaci (Genn.) est infestée de parasites de quatre espèces Aphelinid: Eretomcerus diversiciliatus Silv., E. mundus Mere, Encarsia lutea Masi, et d'une espèce d'Encarsia non-identifiée. Les mouches blanches adultes se déplacent dans leschamps des mauvaises herbes aux cotonniers pendant la période Septembre/Novembre. L'application de large spectre d'insecticides pour enrayer les autres parasites du cotonnier au début de la saison empêche l'établissement du stage d'hôte de la B. tabaci nécessité par les parasites dans les champs de cotonniers pendant la saison de Septembre à Octobre. Par conséquent, le taux de parasitisme est freiené pour n'atteindre son apogée qu'en Janvier vers la fin de la saison. Le taux maximum du parasitisme était de 36,7% pour des champs traités contre 76,8 pour des champs non-traités. Ce qui a promu la B. tabaci au rang de peste permanente pendant toute la saison au lieu d'une peste occasionnelle de début et mi-saison. Des strategies alternatives de lutte contre les pestes de début de saison sont débattues.

Keywords

Bemisia tabaciChrysopa carneawhitefly parasitescotton pestsSudan GeziraBemisia tabaciChrysopa carneaparasites de la mouche blanchepestes du cotonnierSudan Gezira
Type
Research Articles
Information
International Journal of Tropical Insect Science , Volume 7 , Issue 1 , February 1986 , pp. 69 - 73
Copyright
Copyright © ICIPE 1986

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References

REFERENCES

Cowland, J. W. (1934) Report of experimental work carried out by the staff of the section. In The Annual Report of the Agricultural Research Service, Sudan Government, pp. 99–118.Google Scholar
Eveleens, K. G. and Abdelrahman, A. A. (1980) The cotton whitefiy problem: can the tide be turned? Working Paper No. 5, National Pests and Diseases Committee, Sudan.Google Scholar
Gameel, O. I. (1969) Studies on whitefiy parasites Encarsia lutea, Masi and Eretmocerus mundus, Mercet. Hyme-neptera Aphelinidae. Revue Zool. Bot. afr. LXXIX, 65–77.Google Scholar
Gameel, O. I. (1970) The effects of whitefiy on cotton. In Cotton Growth in the Gezira Environment (Edited by Siddig, M. A. and Hughes, L. C.), pp. 265–280. Agricultural Research Corporation, Sudan.Google Scholar
Gerling, D. (1967) Bionomics of the whitefly-parasite complex associated with cotton in Southern California (Homoptera-Aphelinidae). Ann. ent. Soc. Am. 60, 1306–1321.CrossRefGoogle Scholar
Jackson, J. E. (1970) The influence of environment on cotton growth in the Gezira. In Cotton Growth in the Gezira Environment (Edited by Siddig, M. A. and Hughes, L. C.), pp. 78–104. Agricultural research Corporation, Sudan.Google Scholar
Joyce, R. J. V. (1952) General survey of insect pests of crops in the Sudan. In The Annual Report of the Research Division, Sudan.Google Scholar
Joyce, R. J. V. and Roberts, P. (1959) The determination of the size of plot suitable for cotton spraying experiments in the Sudan Gezira. Ann. appl. Biol. 47, 287–305.CrossRefGoogle Scholar
Van Gent, R. V. (1982) Investigations on parasites as a component of integrated pest control of whitefly in cotton. Working Paper No. 8, GCP/SUD/025 of F.A.O.Google Scholar