At chinadialogue, Dave Goulson describes how heavy pesticide use has wiped out wild bees in the south west of China, leaving farmers to take over the job of pollination.
Evidence from around the world points to falling and increasingly unpredictable yields of insect-pollinated crops, particularly in the areas with the most intensive farming. Where crops are grown in vast fields, there are not enough insects to go around. If insecticides are sprayed too frequently, then vital pollinators cannot survive.
The most dramatic example comes from the apple and pear orchards of south west China, where wild bees have been eradicated by excessive pesticide use and a lack of natural habitat.
In recent years, farmers have been forced to hand-pollinate their trees, carrying pots of pollen and paintbrushes with which to individually pollinate every flower, and using their children to climb up to the highest blossoms. This is clearly just possible for this high-value crop, but there are not enough humans in the world to pollinate all of our crops by hand.
Harvey Morris explored the global problem at the International Herald Tribune's Rendezvous blog last week:
Climate change, disease and increased use of pesticides have been blamed as factors in dramatic declines in numbers of bee colonies worldwide — by more than half in 20 years in the case of Britain, according to a recent study by Friends of the Earth, the environmental lobby organization.
Albert Einstein’s reputed warning that “if the bee disappears from the surface of the Earth, man would have no more than four years left to live” continues to chill spines (even though it turns out he probably never said it).
[…] That was maybe going too far, Yves Le Conte of France’s National Agricultural Institute told [French magazine L’Express]. “The consequences would be enormous,” he said. “But to say it would be the end of the world — be serious.”
Although chemicals designed to kill insects may seem an obvious culprit when large numbers of insects start dying, the link between pesticide use and tumbling bee populations is hotly contested. From Wired Science's Brandon Keim, in April:
Researchers led by biologist Chensheng Lu of Harvard University report a direct link between hive health and dietary exposure to imidacloprid, a so-called neonicotinoid pesticide linked to colony collapse disorder, the mysterious and massive die-off of bees across North America and Europe.
The study isn’t without critics, who say doses used in the study may be unrealistically high. But the level of a realistic dose is also a matter of controversy, and even critics say the findings are troubling.
[…] Bayer, the chemical and pharmaceutical giant that manufactures imidacloprid, issued a formal statement denouncing the findings as “spectacularly incorrect” and “based on artificial and unrealistic study parameters that are wildly inconsistent with actual field conditions insecticide use.”