First planted in 1996, Bt corn quickly became hugely popular among U.S. farmers. Within a few years, populations of rootworms and corn borers, another common corn pest, had plummeted across the midwest. Yields rose, and farmers reduced their use of conventional insecticides that cause more ecological damage than the Bt toxin.

By the turn of the millennium, however, scientists who study the evolution of insecticide resistance were warning of imminent problems. Any rootworm that could survive Bt exposures would have a wide-open field in which to reproduce; unless the crop was carefully managed, resistance would quickly emerge.

Key to effective management, said the scientists, were refuges set aside and planted with non-Bt corn. Within these fields, rootworms would remain susceptible to the Bt toxin. By mating with any Bt-resistant worms that chanced to evolve in neighboring fields, they’d prevent resistance from building up in the gene pool.

But the scientists’ own recommendations — an advisory panel convened in 2002 by the EPA suggested that a full 50 percent of each corn farmer’s fields be devoted to these non-Bt refuges — were resisted by seed companies and eventually the EPA itself, which set voluntary refuge guidelines at between 5 and 20 percent. Many farmers didn’t even follow those recommendations.

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See this is the problem: agribusiness creates a halfway decent product (Bt corn), but then expert science and caution go out the window when the profit margin is large enough.

This is also the problem with 50% of the world’s seed stock being owned by three multinationals [X]. The strength of their lobby undermines objective science, fairness, and neutrality.

The dangers of monocultures, be they GM or conventional, are many, but one such danger is that you create breeding grounds for fast-evolving organisms to perfect their mode of predation and pass on any acquired resistance.

This is the flawed logic with control-based technologies, in an evolutionary arms race. We need to work with principles of ecology, not against them.

#GMOs #insects #pest control #evolution

gingbat said: It’s like “why don’t we select for this gene on as massive a scale as possible?” I love the thought of Bt plants, but predators will evolve tolerance to it if they’re hit with it all the time. It’s like super antibiotics resistant germs in hospitals.

Antibiotic resistance is a perfect analogue for this situation: often when we apply an over-zealous control-based logic we actively undermine the natural mechanisms by which resilience and immunity evolve.

Never mind that growing corn monocrops everywhere is such an environmental disaster: for soil, forests, grasslands, and more.