Tag Archives: bacillus thuringiensis

Biotech Crops vs. Pests: Successes, Failures from the First Billion Acres

A new global assessment helps scientists explain why genetically modified crops have suppressed some pests for longer than a decade, while others adapted in a few years.

Since 1996, farmers worldwide have planted more than 1 billion acres (400 million hectares) of genetically modified corn and cotton that produce insecticidal proteins from the bacterium Bacillus thuringiensis, or Bt for short.

Bt proteins, used for decades in sprays by organic farmers, kill some devastating pests but are considered environmentally friendly and harmless to people. However, some scientists feared that widespread use of these proteins in genetically modified crops would spur rapid evolution of resistance in pests. (more…)

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Multi-Toxin Biotech Crops Not Silver Bullets, UA Scientists Warn

The popular new strategy of planting genetically engineered crops that make two or more toxins to fend off insect pests rests on assumptions that don’t always apply, UA researchers have discovered. Their study helps explain why one major pest is evolving resistance much faster than predicted and offers ideas for more sustainable pest control.

A strategy widely used to prevent pests from quickly adapting to crop-protecting toxins may fail in some cases unless better preventive actions are taken, suggests new research by University of Arizona entomologists published in the Proceedings of the National Academy of Sciences.

Corn and cotton have been genetically modified to produce pest-killing proteins from the bacterium Bacillus thuringiensis, or Bt for short. Compared with typical insecticide sprays, the Bt toxins produced by genetically engineered crops are much safer for people and the environment, explained Yves Carrière, a professor of entomology in the UA College of Agriculture and Life Sciences who led the study. (more…)

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UA Entomologists Partner with China to Thwart Bollworm Resistance to Bt Cotton

Researchers at the UA are studying resistance in pink bollworm in China and working to develop strategies against it.

University of Arizona entomologists are joining forces with scientists on the other side of the globe to protect cotton in China from potentially devastating insect pests.

Xianchun Li, associate professor of entomology in the UA College of Agriculture and Life Sciences, and Bruce Tabashnik, head of the department of entomology, both members of the UA BIO5 Institute, are partnering with Chinese scientists to combat insect resistance to genetically engineered cotton plants. (more…)

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Smarter Toxins Help Crops Fight Resistant Pests

*A slight change in molecular structure introduced by genetic engineering gives crop-protecting proteins called Bt toxins a new edge in overcoming resistance of certain pests, a UA-led team of researchers reports in Nature Biotechnology.*

One of the most successful strategies in pest control is to endow crop plants with genes from the bacterium Bacillus thuringiensis, or Bt for short, which code for proteins that kill pests attempting to eat them.

But insect pests are evolving resistance to Bt toxins, which threatens the continued success of this approach. In the current issue of Nature Biotechnology, a research team led by UA Professor Bruce Tabashnik reports the discovery that a small modification of the toxins’ structure overcomes the defenses of some major pests that are resistant to the natural, unmodified Bt toxins. (more…)

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