Impact of Pesticides on Honey Bee Larvae: Development of an Innovative Method for Regulatory Strengthening

New phytosanitary active substances require testing to ensure they are safe for non-target organisms like honey bees, including the brood stage. Traditional methods lacked precision and control for larval exposure. From 2003 to 2007, the authors developed an in vitro individual-rearing technique using 48-well plates and grafting cups, enabling precise control of larval diet and pesticide dosage. This method reduced handling-induced mortality and ensured consistent exposure. It was adopted by the French Biological Test Commission in 2007 and incorporated into OECD guidelines for acute exposure in 2013 and repeated exposure in 2016, strengthening regulatory assessment of pesticide risks to bee brood.