Pesticides More Harmful Than Thought

By TheHindu on 15 Dec 2016 | read

Not just on the honeybees, chemicals in pesticides have severe effect on other pollinators and natural pest controllers such as parasitic wasps, ladybugs, earthworms and many more

An European scientific body said Wednesday that a group of pesticides believed to contribute to mass deaths of honeybees is probably more damaging to ecosystems than previously thought and questioned whether the substances had a place in sustainable agriculture.

The European Commission in 2013 banned the use of three neonicotinoids clothianidin, imidacloprid and thiamethoxam on flowering plants after a separate body, the European Food Safety Authority, found that exposure to the chemicals created high acute risks to bees.

But the chemicals continue to be employed on an industrial scale. A growing body of evidence shows that the widespread use of the pesticides has severe effects on a range of organisms that provide ecosystem services like pollination and natural pest control, as well as on biodiversity, the reports authors said.

Predatory insects like parasitic wasps and ladybugs provide billions of dollars worth of insect control, they noted, and organisms like earthworms contribute billions more through improved soil productivity. All are harmed by the pesticides.

Irreversible impact

Pollination typically by wind, bug or bird is essential to the global food supply. An estimated 75 percent of all traded crops, including apples, soybeans and corn, depend on pollination.

Neonicotinoids are absorbed by a plant so that the neurotoxic poison spreads throughout its tissues, including the sap, nectar and pollen. Far more deadly to insects than to mammals, they do not discriminate between harmful pests and beneficial pollinators.

But the pesticides are also among the most effective insecticides available to farmers. Proponents argue that they are essential to food security, and note that many of the chemicals they replaced were worse in important respects.— New York Times News Service