Sonia Shah: Low-level pesticide exposure leads to evolutionary die-offs

Sonia Shah: Low-level pesticide exposure leads to evolutionary die-offs

January 8, 2010

From Sonia Shah’s article at Yale Environment 360 on low-level pesticide exposure:

… Six years after scientists discovered the fungal assault on amphibians, a mysterious plague began decimating honeybees. Foraging honeybees first started vanishing from their hives, abandoning their broods and queens to certain death by starvation, in 2004. Alarmed beekeepers dubbed the devastating malady “colony collapse disorder.” Between 2006 and 2009, colony collapse disorder and other ills destroyed 35 percent of the U.S. honeybee population.

… Many beekeepers believe that a new class of chemicals based on nicotine, called neonicotinoids, may be to blame. Neonicotinoids came into wide use in the early 2000s. Unlike older pesticides that evaporate or disperse shortly after application, neonicotinoids are systemic poisons. Applied to the soil or doused on seeds, neonicotinoid insecticides incorporate themselves into the plant’s tissues, turning the plant itself into a tiny poison factory emitting toxin from its roots, leaves, stems, pollen, and nectar.

In Germany, France, Italy, and Slovenia, beekeepers’ concerns about neonicotinoids’ effect on bee colonies have resulted in a series of bans on the chemicals. In the United States, regulators have approved their use, despite the fact that the Environmental Protection Agency’s standard method of protecting bees from insecticides — by requiring farmers to refrain from applying them during blooming times when bees are most exposed — does little to protect bees from systemic pesticides.

“The companies believe this stuff is safe,” says U.S. Department of Agriculture (USDA) entomologist Jeff Pettis.

… Proving, with statistical certainty, that low-level pesticide exposure makes living things more vulnerable to disease is notoriously difficult. There are too many different pesticides, lurking in too many complex, poorly understood habitats to build definitively damning indictments. The evidence is subtle, suggestive. But with the rapid decimation of amphibians, bees, and bats, it is accumulating, fast.

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