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OKIsItJustMe

(19,933 posts)
Tue May 9, 2017, 11:34 AM May 2017

Mix Is Key in Reversing Pest Resistance to Biotech Cotton

https://uanews.arizona.edu/story/mix-key-reversing-pest-resistance-biotech-cotton
[font face=Serif][font size=5]Mix Is Key in Reversing Pest Resistance to Biotech Cotton[/font]
[font size=4]UA researchers have discovered an unexpected strategy that can delay, and even reverse, the evolution of resistance by pests to genetically engineered crops. [/font]

May 8, 2017

[font size=3]Insect pests that are rapidly adapting to genetically engineered crops threaten agriculture worldwide. A new study published in the Proceedings of the National Academy of Sciences reveals the success of a surprising strategy for countering this problem: Hybridizing genetically engineered cotton with conventional cotton reduced resistance in the pink bollworm, a voracious global pest.



According to the study's authors, this is the first reversal of substantial pest resistance to a Bt crop. "We have seen blips of resistance going up and down in a small area," said senior author Bruce Tabashnik, a Regents' Professor in the UA's College of Agriculture and Life Sciences. "But this isn't a blip. Resistance had increased significantly across an entire region, then it decreased below detection level after this novel strategy was implemented."

Cotton, corn and soybean have been genetically engineered to produce pest-killing proteins from the widespread soil bacterium Bacillus thuringiensis, or Bt. These Bt proteins are considered environmentally friendly because they are not toxic to people and wildlife. They have been used in sprays by organic growers for more than 50 years, and in engineered Bt crops planted by millions of farmers worldwide on more than 1 billion acres since 1996. Unfortunately, without adequate countermeasures, pests can quickly evolve resistance.

The primary strategy for delaying resistance is providing refuges of the pests' host plants that do not make Bt proteins. This allows survival of insects that are susceptible to Bt proteins and reduces the chances that two resistant insects will mate and produce resistant offspring. Before 2010, the U.S. Environmental Protection Agency required refuges in separate fields or large blocks within fields. Planting such non-Bt cotton refuges is credited with preventing evolution of resistance to Bt cotton by pink bollworm in Arizona for more than a decade. By contrast, despite a similar requirement for planting refuges in India, farmers there did not comply and pink bollworm rapidly evolved resistance.

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http://dx.doi.org/10.1073/pnas.1700396114
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