Scientists from Harvard, in partnership with Monsanto, claim to have discovered a chemical engineering fix to solve the ongoing agricultural problem of insects evolving resistance to the Bacillus thuringiensis (Bt) toxin produced by many genetically modified (GM) crops.

The procedure is described in an April 27 article in the journal Nature.

Brushed aside by the triumphant Nature article and university press release is a thorny problem: Monsanto and other GM companies are the ones responsible for creating the problem they have now partnered with Harvard to “solve.” Also overlooked, is the fact that an ongoing chemical arms race with agricultural pests is unlikely to end in success for the industry.

Engineering new proteins

The article reports the successful use of phage-assisted continuous evolution (PACE) technology to create new forms of Bt toxin. These new toxins should, hypothetically, remain lethal to insects that have evolved resistance to the natural forms of Bt (the researchers tested only that they bind to receptors in the cells of insects resistant to Bt). The scientists boast that it takes only a month to engineer new Bt toxin forms using PACE, compared with a year or more using conventional techniques.

The researchers did not test the new toxins on insects, nor did they demonstrate a method for inserting the new toxin into the seeds of Bt genetically modified organisms (GMOs). Nevertheless, the researchers are already talking of commercial applications of the new method in GMO corn and cotton crops.

While acknowledging that insects will continue to evolve resistance to the new strains, the researchers promise that PACE will simply allow scientists to keep developing new varieties of Bt indefinitely, faster than resistance can evolve.

Monsanto can’t fix a problem it created

It seems appropriate that Monsanto should contribute to solving the problem of Bt resistance, as the company is almost wholly responsible for the phenomenon in the first place. Widespread planting of Bt GMOs dramatically increased insect exposure to the toxin, thereby creating intense selective pressure favoring those individuals with natural resistance.

A similar phenomenon has occurred – and is more well documented – with the evolution of weeds resistant to Monsanto’s blockbuster herbicide Roundup (glyphosate). Despite industry claims that the introduction of Roundup-resistant GMOs would allow decreased herbicide use, the application of Roundup predictably exploded following the commercial introduction of those crops. No longer needing to worry about harming their crops, farmers took to saturating their fields with Roundup as their primary method of weed control. The use of Roundup on the top GMO crops of soybeans, corn and cotton increased tenfold between 1996 and 2012.

Along with this explosion in Roundup use came a wave of Roundup-resistant weeds. In 2011, 34 percent of farmers reported having such weeds. Just one year later, that number had climbed to 49 percent.

“HT [herbicide tolerant] adoption likely reduced herbicide use initially, but herbicide resistance among weed populations may have induced farmers to raise application rates in recent years, thus offsetting some of the economic and environmental advantages of HT corn adoption regarding herbicide use,” the U.S. Department of Agriculture recently wrote.

The science is clear: The strategies being pursued by the agricultural and biotech industries will only fuel more resistance. Already, weeds are emerging that are resistant to 2,4-D, the herbicide of choice for cases where Roundup fails. And rootworms were recently found that were resistant to two varieties of Bt, rather than just the one that had formerly been observed.

Evidence suggests that once an insect has evolved resistance to one Bt variety, it can rapidly evolve resistance to other strains. Thus, the Harvard-Monsanto project may ultimately be futile.

The solution to the problem is actually simple, but is one that big agriculture has been unwilling to implement: just plant fewer GMOs. In 2002, an Environmental Protection Agency (EPA) advisory panel recommended that in order to slow the evolution of Bt resistance, 50 percent of each corn field be planted with non-Bt varieties. Due to biotech lobbying, the EPA ended up recommending only 5–20 percent.

Sources for this article include:

TechTimes.com
GMOInside.org
News.Harvard.edu
Nature.com
Science.NaturalNews.com

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