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

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Article (sc. journal) of N. Xu and M. Fok and L. Bai - 2008

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  • Literature reference
  • Author
  • N. Xu and M. Fok and L. Bai
  • English title of the work
  • Effectiveness and chemical pest control of bt-cotton in yangtze river valley, china
  • Title of the work
  • Effectiveness and chemical pest control of bt-cotton in yangtze river valley, china
  • Year of publication
  • 2008
  • Author's email
  • michel.fok@cirad.fr
  • Journal or magazine
  • Crop Protection
  • URL Address
  • http://halshs.archives-ouvertes.fr/halshs-00324126/fr/
  • Volume of a journal or multi-volume book
  • 27
  • Countries concerned
  • China
  • Associated thesauruses
  • Colire
  • Keywords Colire
  • Biotechnology factor of production cost
    GM seed use conditions
    GM & pest pressure change
    Non-target pest pressure change
    Pest control
    GM cotton
    GM & insecticide use
    Insecticide spray frequency
    Bt cotton
    Insecticide amounts
    Estimation of pesticide use
    Estimation of insecticide use
    Evolution of pesticide use
    Change in pesticide amounts
    GMO use and biodiversity
    Bt cotton
    Change in pest complex
    Pest complex shift
    Pest complex
  • Saved on
  • 2011-12-14
  • Modifed on
  • 2011-12-14
  • Administrated by
  • Fok Michel
  • Abstract
  • 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..