Africanized honey bees (AHB) are descendants of bees brought from Africa to Brazil in the 1950s in an attempt to improve honey production in that country. Some African queen bees escaped accidentally and began to interbreed with the local European honey bees. The resulting AHB hybrids have been moving north ever since and are currently established in Southern California.
In 1997 and 2008, the District responded to incidents where Africanized Honey Bees were unwittingly imported on cargo ships to Contra Costa County. As the lead agency responding to AHB issues, the District's swift response controlled these situations before the bees could escape and establish new colonies.
If the bees are in a high traffic area, such as near a school, appear aggressive or otherwise pose an immediate threat, call the Contra Costa Mosquito & Vector Control District. A technician will try to respond the next working day and each request will be reviewed carefully before proceeding. The District does not treat hives or swarms that are inside a wall or other structure - contact a licensed structural pest control company for assistance.
Honey bees are beneficial insects that are essential for pollination of many native California crops and plants. If a bee swarm does not present an immediate threat, it is best to leave it alone. Bee swarms are a natural occurance as the queen is searching for an ideal nest location. A swarm will usually move onward within a day. Another option is to have a beekeeper relocate the swarm. You can contact the Mount Diablo Beekeeper’s Association at this email address:
vicepresident at diablobees dot org (be sure to replace at with @ and dot with . ).