Small colonies of honey bees in outdoor flight cages were fed insecticide treated syrup and water for 31 days. Consumption and utilization of food and production of sugar honey, wax, and bees were measured. Even at 1000 ppm, methoprene gave no observed hormonal effects, but one formulation (AltosidR5E) eliminated brood production. Although adult kill was not significant, bees had less sealed brood when they were given methyl parathion at 0.02 ppm or parathion at 0.1 ppm. Methyl parathion at 0.2 ppm reduced survival of adults and accumulation of sugar honey. Parathion at one ppm reduced the populations of all stages and accumulation of sugar honey. The results suggest that methoprene is relatively safe for honey bees and that parathion and methyl parathion have deleterious sublethal effects.
Barker, Roy J. and Waller, Gordon D., "Sublethal Effects of Parathion, Methyl Parathion, or Formulated Methoprene Fed to Colonies of Honey Bees" (1978). An. Paper 213.
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