(NaturalNews) Evidence that neonicotinoid pesticides are doing severe damage to ecological integrity and bee populations around the world is now "conclusive," according to a review conducted by an international scientific task force.
The threat posed by these pesticides is on the same scale as that once posed by DDT, the researchers said.
As with many pesticides, neonicotinoids were initially promoted as a supposedly safer replacement for older pesticides. Even then, many scientists warned that the new insecticides could have a devastating ecological impact.
Neonicotinoids are known as "systemic insecticides" because they are sprayed onto seeds and then absorbed into every cell of the plant, making the whole organism poisonous for its entire lifetime.
In recent years, scientists have become increasingly concerned that systemic insecticides are a major factor behind a global decline in pollinators, particularly honeybees. In response to this concern, the environmental organization IUCN brought together an international scientific taskforce to study systemic pesticides in 2011. The researchers spent nearly four years reviewing more than 800 peer-reviewed papers published on the topic over the last 20 years.
Taken together, the studies reviewed point to a negative impact of systemic insecticides, including neonicotinoids and fipronil, on wildlife species worldwide.
"There is so much evidence, going far beyond bees," said researcher Dave Goulson of the University of Sussex, England. "They accumulate in soils, they are commonly turning up in waterways at levels that exceed the lethal dose for things that live in streams. It is impossible to deny that these things are having major environmental impacts."
For example, one of the studies reviewed found that neonicotinoids were accumulating in Dutch water supplies and devastating populations of aquatic invertebrates. This, in turn, destroyed the food supply of larger creatures, from trout and salmon to wading birds. Other studies found that neonicotinoids were killing creatures as diverse as butterflies, birds, earthworms and freshwater snails.
As bad as DDT
As systemic pesticides work in a fundamentally different fashion than older chemicals, the researchers warn that it is impossible to measure their toxicity using older tests. Although the pesticides are not known to accumulate in animal tissues the way that older pesticides, such as DDT, do, they are actually 6,000 times more toxic.
Farmers have come to over rely on systemic insecticides much as they once over relied on DDT, the task force warned. These chemicals now make up a third of the global insecticide market.
"We have forgotten those lessons and we're back to where we were in the 1960s," Goulson said. "We are relying almost exclusively on these insecticides, calendar spraying 20 times or more onto a single field, it's a completely bonkers way."
As systemic insecticides can be sprayed onto seeds before planting, many farmers simply apply them prophylactically, rather than waiting for an infestation as with older pesticides. This use is irresponsible, the researchers warned.
"The more they are used, the stronger the selective pressure you place on pest insects to become resistant to them," Goulson said. "Using them as prophylactics is absolute madness in that sense."
Another recent study revealed that more than half of the "bee-friendly" plants sold at Home Depot, Lowe's and Walmart have been prophylactically treated with neonicotinoids and are, thus, actually killing the pollinators they are designed to attract.
"Unfortunately," authors of that study wrote, "home gardeners have no idea they may actually be poisoning pollinators through their efforts to plant bee-friendly gardens."
To make matters worse, there is no evidence that neonicotinoid use actually provides any agricultural benefit.
"We have been using these things for 20 years and there's not a single study that shows they increase yield," Goulson said. "If they don't benefit yield we should stop using them."