LE MONDE 01/09/11 Un maïs OGM Monsanto mis en échec par l'"insecte à 1 milliard de dollars" LE MONDE | • Mis à jour le | Par Hervé Morin L'"insecte à 1 milliard de dollars", comme l'ont surnommé les agriculteurs américains, a une nouvelle fois déjoué les défenses qu'ils avaient disposées contre lui dans leurs champs, sur les conseils de Monsanto.
La chrysomèle du maïs, Diabrotica virgifera, de son nom latin, a fait une percée contre un maïs transgénique de la firme américaine. Le petit coléoptère avait déjà développé une stratégie pour échapper à la rotation des cultures, qui vise à le priver de sa pitance favorite lors de son éclosion : il s'est déjà montré capable de survivre sur du soja et de surseoir un an ou deux à la sortie de terre pour se retrouver dans son cher maïs. Les agriculteurs américains, qui ont aussi vu l'efficacité des insecticides diminuer au fil des ans, croyaient avoir trouvé la parade ultime, avec un OGM capable de produire lui-même une toxine grâce à un gène transplanté d'une bactérie, Bacillus thuringiensis.
GMO SAFETY 26/11/08 Effects of the cultivation of Diabrotica-resistant Bt maize on the maize ecosystem II. Nov 26, 2008 Research Projects Print Send (2005 – 2008) RWTH Aachen University, Institute of Environmental Research (Biology V), Chair of Environmental Biology and Chemodynamics Topic The aim of this project is to investigate the effect of Bt maize that is resistant to the Western corn rootworm on various organisms in the maize ecosystem, in comparison with conventional maize varieties.
The focus in this part of the research is on effects of the Bt protein (Cry3Bb1) on arthropods in the herbaceous layer such as beetles, heteropterans and cicadas and their antagonists, such as spiders. Further investigations will focus on the potential effect of Bt maize pollen on caterpillars that live on the associated farmland plants. Summary Arthropods of the herbaceous layer and their antagonists Variety-related differences in the incidence of arthropods were found both in the maize ears and in the herbaceous layer. Z. scutellaris was the most common species of leafhopper found (65 per cent).
Results. ARS USDA - SEPT 2010 - Rooting Out Rootworm Resistance. PLOS 29/06/11 Field-Evolved Resistance to Bt Maize by Western Corn Rootworm. Background Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests.
N., and D. A. Andow. 1996. Implementing management of insect resistance to transgenic crops. Agric. Bates, S. Boetel, M. Branson, T. Branson, T. Denholm, I., and M. FOOD FREEDOM 24/08/11 Monsanto GM Corn in Peril: Beetle develops Bt-resistance. By Rady AnandaFood Freedom Nature herself may be the best opponent of genetically modified crops and pesticides.
Not only plants, but insects are also developing resistance. The Western rootworm beetle – one of the most serious threats to corn – has developed resistance to Monsanto’s Bt-corn, and entire crops are being lost. [Image] Farmers from several Midwest states began reporting root damage to corn that was specifically engineered with a toxin to kill the rootworm. Bacillus thuringiensis – Bt – is a bacterium that kills insects. Two-thirds of all US corn is genetically modified per the USDA, and the bulk of that is Bt-corn. In response to the July 2011 study, Monsanto said only the “YieldGard® VT Triple and Genuity® VT Triple PRO™ corn products” are affected. “It appears he has demonstrated a difference in survival in the lab, but it is too early to tell whether there are implications for growers in the field.”
Roundup and birth defects: Is the public being kept in the dark? AP 29/08/11 Monsanto shares slip on bug-resistant corn woes. AFP 30/08/11 Un maïs OGM cible d'un insecte auquel il devait résister. K STATE EXTENSION - AGRONOMY E-UPDATES 12/08/11 Au sommaire: Corn rootworm resistance to Bt trait documented in Iowa. AGPROFESSIONAL 05/08/11 Iowa reports first in-field resistance to Bt corn. The first documented case of in-field resistance to Bt corn targeting rootworms has been confirmed recently in Iowa.
Aaron Gassman, Iowa State University entomologist, and other researchers had received multiple reports of high damage to Bt corn in northeastern Iowa. The group collected adults and eggs from the area. Rearing the larvae in the laboratory on Bt hybrids revealed that the larvae were able to survive on Bt corn hybrids expressing the Cry3Bb1 toxin at levels similar to survival on non-Bt corn. It has been speculated that insects would eventually build up resistance to the Bt protein over time since corn rootworm Bt toxins are not high dose toxins, which means many larvae survive exposure and reach adulthood. Christian Krupke, Purdue University, entomologist reports, “Hybrids expressing this toxin include those formerly labeled as Yieldgard RW and VT3 hybrids.
The majority of corn planted in the U.S. is Bt corn, and the Cry3bb1 toxin is the major one deployed against rootworms. CORN AND SOY BEAN DIGEST 30/08/11 Bt Resistant Corn Borers Spur Concerns. Aachen University - 2011 - Thèse en ligne : Potential impact of Diabrotica resistant Bt-maize expressing Cry3Bb1 on ground beetl. Si le lien ci-dessus AACHEN UNIVERSITY ne s'ouvre pas, accès via CACHE.