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Submitted to: IOBC/WPRS Bulletin (Abstract for Conference Proceedings)
Publication Type: Proceedings Publication Acceptance Date: 8/24/2007 Publication Date: 10/6/2008 Citation: Naranjo, S.E. 2008. Integrating insect-resistant GM Crops in pest management systems. IOBC/WPRS Bulletin Vol 33, pp. 15-22. Interpretive Summary: Crop plants that have been genetically-modified (GM)to produce the protein toxins of a common soil bacteria, Bacillus thuringiensis (Bt) are currently grown in many countries. Bt cotton and Bt maize are grown on 12.1 and 20.1 million hectares worldwide. These crop plants allow very selective control of key bollworm, borer and root pests and have been estimated to reduce the volume of insecticide active ingredient by 101.5 million kg over the past 10 years while increasing farm income by $9.87 billion worldwide. Host plant resistance via Bt cotton and maize represents one of many pest management tactics that can be integrated in IPM systems. Reductions in insecticide use through adoption of Bt crops have broadened opportunities for biological control of all cotton and maize pests. Most other pest management tactics have remained largely unchanged or modified only slightly in Bt crops. Many studies have demonstrated enhanced natural enemy abundance in Bt crops compared with conventional crops subject to broad-spectrum insecticides. A few studies also have focused on understanding the functional contribution of this natural enemy conservation. In both systems, several non-target pests have become more problematic in Bt crop fields in some countries largely due to reductions in insecticide use for target pests. Changes in IPM practice, enhanced biological control and the emergence of non-target pests are further illustrated by examples from the Bt cotton system. Technical Abstract: In 2006, GM cotton and maize with insect resistance were grown on 12.1 and 20.1 million hectares in 9 and 13 countries, respectively. These insect resistant GM crops produce various Cry toxins from Bacillus thuringiensis (Bt) and provide highly selective and effective control of lepidopteran and coleopteran pests, primarily bollworms, borers and rootworms. Between 1996 and 2005 the deployment of Bt cotton and maize reduced the volume of insecticide active ingredient by 94.5 and 7.0 million kg and increased farm income by US$7.51 and 2.37 billion, respectively. Host plant resistance via Bt cotton and maize represents one of many pest management tactics that can be integrated in IPM systems. Reductions in insecticide use through adoption of Bt crops have broadened opportunities for biological control of all cotton and maize pests. Most other pest management tactics have remained largely unchanged or modified only slightly in Bt crops. Many studies have demonstrated enhanced natural enemy abundance in Bt crops compared with conventional crops subject to broad-spectrum insecticides. A few studies also have focused on understanding the functional contribution of this natural enemy conservation. In both systems, several non-target pests have become more problematic in Bt crop fields in some countries largely due to reductions in insecticide use for target pests. Changes in IPM practice, enhanced biological control and the emergence of non-target pests are further illustrated by examples from the Bt cotton system. |
