Wasp, Yellowjacket and Bee Removal in Los Angeles

A yellowjacket colony follows a calendar. A single mated queen that survived the winter starts the nest in late winter or early spring, and through midsummer her workers mostly hunt other insects to feed the growing brood. By late summer the colony stops growing quickly and the workers switch to sugar, which is when they appear at trash cans, pet bowls, ripe fruit and backyard meals. UC Integrated Pest Management notes that defensive behavior also rises as food gets scarcer. A nest nobody noticed in May is the one that ends a Labor Day barbecue.

Most yellowjacket colonies die out after one season, but UC researchers point out that in coastal California south of San Francisco, and in very mild winters, some colonies survive for several years. In the Los Angeles basin and the San Gabriel Valley, that means a nest in a slope or a wall void cannot be counted on to disappear when the weather cools.

Who to call depends on where the nest is. The San Gabriel Valley Mosquito & Vector Control District, which serves 26 valley cities, does not handle bees and refers those calls to other agencies or private pest control.

Los Angeles County Public Works directs beehives on county property to the Agricultural Commissioner/Weights & Measures Department at (626) 575-5471, and says hives at a private residence or other private property may require a private pest control company; for a concern about vector-borne disease, the same county answer lists the Los Angeles County West Vector & Vector-Borne Disease Control District at (310) 915-7370. For a nest on your own house, apartment building or business, a private company such as PesPro is usually the call. [1] [6] [5]

For most people a sting means pain and swelling that fades. For people allergic to the venom, the CDC's National Institute for Occupational Safety and Health (NIOSH) warns that a sting from a bee, wasp or hornet can trigger anaphylaxis, a severe and potentially life-threatening allergic reaction that needs immediate emergency care.

NIOSH advises people with a history of severe reactions to carry an epinephrine auto-injector and wear a medical ID. If someone in your household has that history, plan for them to be indoors, away from the work area, while a nest is treated or removed, and call 911 for any sign of a severe reaction.

Many stings at once are a separate risk that applies to everyone. A wasp's stinger has no barbs, so a single yellowjacket can sting repeatedly, especially when it gets trapped inside clothing. UC IPM notes that multiple-sting encounters can damage tissue and lead to kidney problems that sometimes require dialysis. That is why a disturbed yellowjacket nest in a lawn being mowed, or a bee colony hit by a leaf blower, is more dangerous than a single stray sting.

If you are stung by a honey bee, scrape the stinger out quickly with a fingernail or wipe it away with gauze; NIOSH says never to squeeze it or use tweezers, then wash the area and apply ice. If several insects are attacking, get inside a building or car and stay there even if a few follow you in. Do not jump into a pool: UC Riverside entomologists note that the bees will still be waiting nearby when you surface. [4] [1] [3]

Africanized honey bees are part of the landscape here. UC Riverside records that they were first found in California in October 1994, and that by 1999 they had been detected in most areas of Los Angeles, Orange, San Bernardino, Riverside, San Diego and Imperial counties, plus parts of Kern and Ventura. UC IPM's guide to removing bee swarms and hives lists all Southern California counties among the areas with Africanized bees.

The differences that matter are behavioral, not visual. Africanized bees look nearly identical to European honey bees, and only microscopic measurements or DNA testing can tell them apart. They are disturbed more easily, more bees join in defending the colony, and they will follow an intruder over a longer distance.

Africanized colonies also swarm more often and will settle in small cavities near the ground, such as water meter boxes and overturned flower pots. UC IPM notes that spring swarms of European bees are usually docile, while Africanized swarms, and swarms that have run out of food, can be much more aggressive.

None of this means a bee visiting your rosemary is a threat. What it changes is how an established colony should be approached. Because nobody can tell by looking, every colony in a wall or meter box and every swarm that lingers should be treated as if it could be defensive: no mowing, edging, string-trimming or leaf-blowing near it, children and pets kept away, and no attempts to knock it down, hose it off or spray it. That caution is also why live relocation is offered only when the colony's behavior and access make it reasonable. [3] [2]

Store-bought wasp sprays are built for a nest you can see and reach, and most yellowjacket problems in Los Angeles yards are neither. With a ground nest, the hole you see may sit well away from the nest chamber, so the spray never reaches the colony.

UC IPM notes that wasps attack when they sense insecticide being applied to the nest, that stinging is still likely after dark even with jet sprays rated to 20 feet, and that agitated, partly poisoned wasps can turn up some distance from the nest the next day. UC also states that removing the nest is not practical for underground or wall-void colonies.

Height turns a bad outcome into a dangerous one. Aerial yellowjacket nests and paper wasp nests are often under second-story eaves, and a defensive response while you are on a ladder is how a few stings become a fall. A wall-void colony whose entrance gets caulked shut is still alive inside a wall that the workers can already moisten and soften, the same behavior UC describes turning a damp patch into a hole in a ceiling.

Professional treatment changes the order of operations rather than the bravado. PesPro confirms the species and finds the actual nest first, works in full protective equipment during low-activity hours when foragers are home, applies products labeled for that nest type directly where the colony lives, removes accessible nests, and treats the nest site so returning wasps and next year's queens are discouraged from rebuilding there. A small paper wasp nest on a back fence that nobody walks past may not need treatment at all; UC notes paper wasps rarely sting unless the nest is near doors, windows or busy paths. [1]

Scout bees look for a dark cavity of about nine gallons, four at minimum: a stucco wall void, a soffit, a chimney, the space under a deck, a utility box, a barbecue grill or a water meter box. Once a colony moves in it builds comb fast. UC IPM notes that a mature colony can hold up to 100 pounds of honey along with many pounds of bees and comb. A colony that arrived only days ago can sometimes be screened out, but an established one cannot simply be locked in.

Sealing the entrance, or killing the bees and leaving the comb, is the most expensive mistake in bee control. Without bees to tend it, honey absorbs moisture and ferments, the gas bursts the wax cappings, and honey runs down through drywall, ceilings and floors. Brood and dead bees rot and smell, and trapped bees may find their way into living spaces.

UC IPM also notes that pesticides labeled for bees inside structures are restricted to licensed operators, that bees, honey and wax killed with pesticide must be handled as hazardous waste, and that the beeswax odor left behind keeps attracting new swarms long after the colony is gone.

The order that works is: locate the nest, open enough of the wall or structure to reach all of the comb, remove the bees, remove every piece of comb and honey, fill the cavity with insulation or expanding foam, and only then seal the entrance. PesPro offers live relocation when the colony and access make it feasible.

When the colony or the access does not allow it — a defensive colony, a nest that cannot be reached safely — targeted treatment is used, and the comb still has to come out. We explain which situation you are in, and whether a wall or soffit needs to be opened, before any work starts. [2]

Bee-proofing is mostly about holes. UC IPM recommends sealing any opening about the size of a pencil or larger that leads into a cavity, covering larger openings such as vents with screen of at least six mesh per inch, and filling unused cavities with expanding foam so they are no longer worth a scout's attention.

After a hive is removed, inspect the entire side of the building where the old entrance was, and both sides if it was on a corner, because scouts will keep checking the spot that smells of wax. Keep water meter and irrigation valve box lids intact and closed.

Yellowjacket prevention is about food. Keep pet food, drinks and garbage covered, put lids on soda cans outdoors, and pick up fallen fruit under citrus, fig and stone-fruit trees before it ferments. Commercial lure traps baited with heptyl butyrate mainly catch western yellowjackets and should hang around the edge of the yard, away from where people sit.

UC IPM adds that homemade water traps with a protein bait work best as queen traps in late winter and early spring, and that the bait stations once sold for yellowjackets left the market in the early 2000s, with the replacement esfenvalerate products not shown to work in research trials.

On a PesPro visit, prevention is part of the job rather than an afterthought: we point out the attractants and entry points we find around the property and can apply preventive treatments to eaves, overhangs and the other spots where wasps keep rebuilding. Commercial properties with patios, loading docks or high foot traffic can set this up as a recurring preventive program. [2] [1]