New pesticide may harm bees as much as those to be replaced

PARIS: A new class of pesticides positioned to replace neonicotinoids may be just as harmful to crop-pollinating bees, researchers cautioned Wednesday.

In experiments, the ability of bumblebees to reproduce, and the rate at which their colonies grow, were both compromised by the new sulfoximine-based insecticides, they reported in the journal Nature. Colonies exposed to low doses of the pesticide in the lab yielded significantly less workers and half as many reproductive males after the bees were transferred to a field setting.

"Our results show that sulfoxaflor", one of the new class of insecticide, "can have a negative impact on the reproductive output of bumblebee colonies," said lead author Harry Siviter, a researcher at Royal Holloway University of London.

As with neonicotinoids, sulfoxaflor does not directly kill bees, but appears to affect the immune system or the ability to reproduce. Foraging behaviour, and the amount of pollen collected by individual bees remained unchanged in the experiment. The study has been published amid legal challenges and shifting national policies on neonicotinoids, among the most commonly used insecticides in the world. In April, European Union countries voted to ban three neonicotinoid-based products in open fields, restricting use to covered greenhouses.