|Crate & Barrel's Insect Trap—$9.95|
It is time to start thinking about how to wage war on those bastardic little flying torpedos of doom, the ground-nesting western yellow jackets. According to recommendations from the University of California's state-wide Integrated Pest Management program, there is a 30-45 day period in the spring when the new queens emerge to scout out locations where they will build their nests.
A single reproductive female can produce a population of 1,500 to 15,000 individuals, depending on the species. Yellow jackets will typically make nests in rodent burrows, but they are not picky. Protected spaces like voids in walls and ceiling spaces work just as well. If the space is not big enough for the colony, yellow jackets will increase the size by moistening the area and digging. If the colony establishes itself inside of a house, worker drones will create a wet patch and dig through drywall to enlarge the area.
In my case, yellow jackets invaded the rafters of our roof through a space under the eave just outside of my son's bedroom. When I got up onto a footstool to take a closer look at what sounded like a buzzing area in the ceiling, I saw tiny insect legs poking through a hairline crack in the paint. At that moment, all that stood between me and potentially thousands of yellow jackets was the thin skin of the ceiling paint.
I closed the door and made a beeline (heh) to the hardware store to get an adhesive wire screen patch that was large enough to cover the area on the ceiling. Then, I applied a layer of plaster and blended it into the ceiling texture to seal the area for good. After that, we filled every nook and cranny that we could find around the outside of our house with steel wool. That works as a deterrent for roof rats, as well. To finish off the nest, I had to call a professional exterminator to shoot some abrasive powder into the roof to kill the yellow jackets.
Yellow jackets are scavenging wasps, not bees. Yellow jackets will invade honey bee hives and kill the bees, if given the opportunity. Paper wasps, on the other hand, are agriculturally beneficial insects and prey on all sorts of destructive caterpillers, including corn earworms and hornworms, which they catch and take back to their larvae. Adult paper wasps feed primarily on nectar and honeydew.
Trapping yellow jackets is an ongoing effort that starts in the spring and continues on through the fall. Trapping the queen in the spring has the potential to provide an overall reduction in the yellow jacket population for the season. The IPM website recommends lure traps as the best way to capture queens. Water traps, like this neat one sold by Crate & Barrel, also work well for capturing queens during late winter and early spring.
The more traps that are put out in the spring, the greater the liklihood of reducing nests later in the summer. One trap per acre is adequate for depletion trapping of queens; more may be necessary during the summer and fall after the colonies have grown and are established.
Put out your traps now and start planning for a healthy & happy summer!