Effectiveness and chemical pest control of bt-cotton in yangtze river valley, china

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Article de revue scientifique de N. Xu and M. Fok and L. Bai - 2008

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  • Référence bibliographique
  • Année de publication
  • 2008
  • Auteur(s)
  • N. Xu and M. Fok and L. Bai
  • Titre du document
  • Effectiveness and chemical pest control of bt-cotton in yangtze river valley, china
  • Titre en anglais
  • Effectiveness and chemical pest control of bt-cotton in yangtze river valley, china
  • Adresse email de l'auteur
  • michel.fok@cirad.fr
  • Adresse URL
  • http://halshs.archives-ouvertes.fr/halshs-00324126/fr/
  • Journal ou Magazine
  • Crop Protection
  • Volume
  • 27
  • Pays concerné(s)
  • Chine
  • Thésaurus associé(s)
  • Colire
  • Mots-clé(s) Colire
  • Facteur biotechno des coûts de production
    Conditions d'utilisation des semences GM
    OGM et changements de la pression des ravageurs
    Changement de la pression des ravageurs non cibles
    Contrôle des ravageurs
    Coton transgénique
    OGM et utilisation d'insecticides
    Fréquence des épandages insecticides
    Coton Bt
    Quantité d'insecticides
    Estimation de l'utilisation des pesticides
    Estimation de l'utilisation des insecticides
    Évolution de l'utilisation des pesticides
    Changement dans les quantités de pesticides
    Utilisation d'OGM et biodiversité
    Cultivars
    Coton Bt
    Changement du complexe des ravageurs
    Changement du complexe des ravageurs
    Complexes de ravageurs
  • Enregistré le
  • 2011-12-14
  • Modifié le
  • 2011-12-14
  • Administré par
  • Fok Michel
  • Résumé
  • The sustainability of Bt-cotton in China, at least along Yellow River Valley, has been questioned, so this paper examines its effectiveness along Yangtze River Valley, where Bt-cotton is also widely sown, to determine what might be the factors beneath the limited or reduced effectiveness being observed. The analysis is based on the data collected for several years from many locations in the Yangtze River Valley Varietal Experiment Network to provide information on the varieties and their agronomic performance, on the control of their GM characteristic, on the expression of the Bt-gene and on chemical control practices against cotton pests.. All varieties declared to be Bt-cotton were confirmed to have the Bt-gene, the expression of which was assessed in three ways: through the analysis of Bt-protein production and through indoor and outdoor bioassays. Gene expression varied substantially between varieties and between years for the few varieties which were tested in two subsequent years.. The Bt-cotton varieties being sown cannot control bollworms totally even early in the growing season, so surviving larvae could inevitably be observed, and this led farmers (or professionals in charge of supplying technical assistance to farmers) to spray chemicals regardless of the real infestation level. This demonstrates behaviour aimed at eradication of the pests as bollworms seem to be treated chemically more often than is required and far earlier than necessary on the first two generations of H. armigera. The chemical control of the Bt-cotton in Yangtze River Valley hence is not optimal, thus farmers are paying high prices for varieties which are not totally resistant to bollworms and pest control costs are not reduced to the extent that they might expect, lowering the profitability of cotton production. Also chemical protection costs are not decreasing as those pests unaffected by the Bt-gene, mainly but not exclusively sucking ones are requiring more control. This is illustrative of a phenomenon of pest complex shift which deserves more attention in following up the Bt-cotton use..