Just about any insecticide will kill bees as they are very susceptible to poisons. Dusts are the best method of eradication in an accessible position such as on a tree branch or under eaves. The best time of the day is either early morning or late afternoon. This is when they remain inactive inside the colony. Dusting in these times does not flush them out and it is rarely necessary to retreat. Treatment during sunny hours will not always destroy the entire colony, although the majority of the colony will die.
If you have European wasps or bees nesting on your property, (private or leased), it is your responsibility to have them removed. It is recommended you call a pest control company to exterminate the problem swarm. If you have your own protective clothing the best time to exterminate a nest is early in the morning or late in the afternoon. These times will ensure the majority of the colony will be in the nest.
WARNING: Treating Bees yourself can be dangerous. Call a Pest Professional to safely treat your Bee problem.