The toxicity of diflubenzuron to honey bee (Apis mellifera L.) colonies in apple orchards

Abstract
SUMMARY: The effect of diflubenzuron on honey bees in apple orchards in southeastern England was studied in 1976. In two experiments apple trees cv. Cox's Orange Pippin, in full flower and with honey bees foraging on the blossom, were sprayed with diflubenzuron at 0.11, 0.20 or 0.40 kg a.i.†/ha, HCH at 0.25 kg a.i./ha or malathion at 2.52 kg a.i./ha. Diflubenzuron did not reduce the numbers of adult or larval bees, whereas HCH or malathion killed many adult bees. In a third experiment in 1978 in eastern England diflubenzuron at 0.22 kg a.i./ha was sprayed on to bees returning to their hive. Neither adult nor larval bees were killed by this treatment. Small quantities (0.11 and 0.30 μg/g) of diflubenzuron were found in samples of honey from hives sited in plots treated with this insecticide.