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International Journal of Tropical Insect Science

, Volume 10, Issue 6, pp 787–794 | Cite as

Sudanese Experience in Integrated Pest Management of Cotton

  • Asim A. Abdelrahman
  • Badar Munir
Special Section Pest Management and the African Farmer

Abstract

As a background to an IPM project, this paper describes pesticide treatment of cotton in Sudan Gezira, starting in 1945/46. Until the end of the 1950’s, one treatment per season was sufficient to control the only important pest, the jassid, Empoasca lybica, but the number of treatments increased during the 1960’s (from 3 to 5) and has since the early 1970’s been 6–9.

The continuous use of pesticides has resulted in changes of the pest complex, ultimately creating “hyper” pests such as the whitefly (Bemisia tabaci), cotton bollworm (Heliothis armigera) and aphids (Aphis gossypiï). The increase in number of applications of pesticide is coupled with the rising costs of pest control and a stagnant yield. The stickiness problem created by the honey dew of whitefly and aphids increased with the rising number of sprays. The exclusive use of chemical control not only failed to improve the quality or quantity of the yield, but put a great strain on the national economy as well.

The Sudan therefore requested the FAO to initiate an IPM project starting in 1979, with financial support from the Netherlands. During the past 2 years support has also been given by the World Bank. The IPM approach has given very valuable results during the last two seasons when large (more than 100 acres) plots in the Gezira and Rahad Schemes were left unsprayed with the objective of investigating the potential of the natural enemies in the absence of pesticides, and to compare findings with population trends of pest and beneficial organisms in the fields subjected to conventional chemical control.

The first significant finding was that Bemisia tabaci and Aphis gossypiï can be managed at desirable levels by their indigenous natural enemies, and that their outbreaks are attributed to the decimation of these natural enemies by chemical treatment. Populations of beneficial arthropods were consistently much lower in the fields which received regular pesticide applications.

The result of the large-scale experiments indicate that Empoasca lybica is the only really damaging pest (“key pest”) in the Gezira because of the absence of natural enemies to regulate its population. Control of E. lybica in the 1940’s and 1950’s resulted in the creation of Heliothis armigera as a major pest. This situation necessitated early season applications of pesticides to suppress H. armigera, which further reduced the role of the natural enemies of B. tabaci and A. gossypiï. Both have developed into major pests of regular occurrence.

Cotton farmers in Gezira are now faced with a complex of very serious pests. In order to solve this problem, we will have to make drastic changes in pest control strategies and to adopt an IPM approach as soon as possible. The biological control of H. armigera is considered as first priority in order to avoid the early season application of pesticides. Trichogramma pretiosum was introduced from the USA and released in the Rahad Scheme in 1988/89. The preliminary results are very promising.

Cultural and biological control of E. lybica will be attempted in order to further reduce pesticide applications. The control of this pest by the use of “milder” pesticides is also included in the programme.

The presently used threshold leveis for all major pests are very low, and are under revision through properly conducted large-scale experiments.

Key Words

Integrated Pest Management Empoasca lybica Bemisia tabaci Heliothis armigera Aphis gossypii Trichogramma pretiosum 

Mots Clefs

Gestion integrée des ravageurs Empoasca lybica Bemisia tabaci Heliothis armigera Aphis gossypii Trichogramrna pretiosum 

Résumé

Ce publication revue l’utilisation des insecticides sur Ie coton a Gezira (Soudan) depuis 1945/46 comme base de la gestion integrée des ravageurs. Jusqu’a la fin de 1950 un seul traitement a l’insecticide par saison etait suffisant pour controler Empoasca lybica, mals avec le temps le nombre de traitement avait augmenté de 3 a 5 fois des ie debut des années 60 et des le debut dès années 70 entre 6 a 9. L’utilisation continue des insecticides entraina dès changements de la population des ravageurs avec la creation des super-ravageurs telsque Bemisia tabaci, Heliothis armigera et Aphis gossypii. L’accroissement du nombre d’application d’insecticides couplé avec le prix de revient de la lutte contre les ravageurs et le rendement stagnant ont pour leur part compliqué le probleme sans pour autant ameliorer la quantite de la production. Ce controle chimique etait seulement une sang sue pour l’economie nationale. Pour cette raison le soudan a demander a la FAO d’initier un projet de gestion integrée des ravageurs a partir de 1979 grace a un support financier des pays bas suivit d’une assistance de la banque mondiale. L’approche de cette gestion integrée a donné des resultats importants pendant les deux dernieres saisons lorsque des champs très larges (plus de 100 acres) a Gezira et Rahad n’ont pas èté pulverisé pour analyser les potentialités des ennemies naturelles et de comparer ces resultats avec ceux des champs pulverisés. Il a èté trouvé que Bemisia tabaci et Aphis gossypii peuvent etre controler a un niveau satisfaisant grâce a leur ennemies naturels indigenes et que leur attaque est du au fait que leur ennemies naturels ont ete extermine par les traitements chimiques. La population des arthropodes benefiques fut reduite sur les champs qui ont èté traité par des produits chimiques. Le resultat de cette experimentation a demontre que seul Empoasca lybica est le ravageur le plus important a Gezira, parcequ’il n’y pas d’ennemies naturels. La lutte contre E. lybica entre 1940 a 1950 a contribue a la creation de Heliothis armigera comme ravageur. Cette situation nessecita l’application d’insecticides au debut de la saison, mais malheureusement ceci entraina la suppresion des ennemies naturels de B. tabaci et A. gossypii. Les paysans a Gezira sont confrontés a un multitude des ravageurs. Pour cela on doit prendre des mesures pour changer les strategies de lutte et d’adopter la gestion integree des ravageurs aussi vite que possible. La lutte biologique contre H. armigera est considerée comme la premiere priorite pour eviter l’application des insecticides. Trichogramrna pretiosum fut introduit des Etats Unis dans la zone de Rahad entre 1988/89. Les resultats obtenus sont encourageant. Des essais pour controller E. lybica en se basant sur les pratiques culturales et la lutte biologique seront faits.

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Copyright information

© ICIPE 1989

Authors and Affiliations

  • Asim A. Abdelrahman
    • 1
  • Badar Munir
    • 2
  1. 1.Agricultural Research CorporationWad MedaniSudan
  2. 2.Food and Agriculture OrganizationRomeItaly

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