Low Doses of Controversial Insecticide May Harm Friendly Insects

Chemical & Engineering News    By Puneet Kollipara   3/14/14 

A neonicotinoid compound affects fruit flies’ ability to have offspring even at low doses.

For at least one member of a controversial class of insecticides, low doses may cause as much harm to nontarget insects as high doses do, according to a new study. The number of offspring that fruit flies produce drops significantly when the insects are chronically exposed to nanomolar concentrations of imidacloprid, a member of the neonicotinoid insecticide group (Environ. Sci. Technol.2014, DOI: 10.1021/es405331c).

In Europe, policymakers have moved to temporarily ban some of the neonicotinoids based in part on previous studies that showed that honeybees exposed to low doses of the compounds developed significant behavioral changes. The new study builds on these low-dose findings and suggests regulators need to rethink how they assess the safety of chemicals applied in the environment, says Dennis vanEngelsdorp, an entomologist at the University of Maryland, College Park, who wasn’t involved in the work.

The main way scientists determine a chemical’s toxicity is to...