Researchers call for updated regulatory studies
Two novel insecticides, sulfoxaflor and flupyradifurone, have been found to have an equally negative impact on beneficial insects as the neonicotinoid insecticides they have replaced.
Having looked at the literature, researchers from the University of Texas at Austin, US say that what stands out is how similar the sub lethal effects of the new insecticides are to the ones they have replaced. ‘They can cause bees to have a lower reproductive output, which is obviously very important,’ the researchers said. Sulfoxaflor and flupyradifurone both kill pest species that are resistant to neonicotinoids. Yet the review highlights studies indicating that flupyradifurone can increase risk of death in bumblebees at exposure levels typically found outside, and sulfoxaflor can kill bee larvae at normal spraying concentrations. It has been reported that spraying sulfoxaflor led bee colonies to produce fewer workers.
Cautioning against directly replacing neonicotinoid insecticides, the researchers added; ‘The regulatory process to screen pesticides coming to the market simply hasn’t changed since the neonicotinoids in the 1990s. There are [no additional] safety guards.’
The researchers said that honeybees are used as the model species by regulators, but there are 20 000 bee species. Bumblebees and other wild bees should be included in regulatory studies. The researchers also highlight that in the field, bees will be exposed to a cocktail of agrochemicals which may interact and produce worse outcomes for bees and beneficial insects. Fungicides and insecticides are regulated as single compounds. ‘As with approved human drugs, the impact of insecticides should be monitored after approval, for unanticipated negative ecological consequences,’ the researchers said.
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