It usually takes about 2-3 days to completely die off, but at times, it might take a longer time, depending on the species and the populace of bees in the colony. Even, when they are professionally treated by a bee exterminator Williamsville NY, they won’t die off instantly, as they fly back and forth from the hive. We suggest our clients to wait for at least a week for the bees to completely die off. Talk to an expert today at 716-773-2844.