Yellow jackets belong to same family as bees, wasps, hornets, and ants. Due to their huge population in late summer yellow jackets are generally considered the most dangerous of the social insects and are responsible for over half of all insect stings.
Yellow jackets build their nest in the ground, on the ground (in leaf litter) or attached to retaining walls or tree limbs. This nesting practice puts them in close contact to humans. Unlike bees, yellow jackets can sting repeatedly which can make an attack even more painful.
Yellow jackets require two types of food: sugar from nectar, fruit, soft drinks, etc., (utilized by the adults for high energy) and protein from garbage and carrion (which is fed to the larvae). For this reason they are attracted to picnic and recreational areas, back yards, garbage cans, pet food, fallen fruit and sometimes even to soft-drink machines.
The methods of control are barriers, traps and insecticides. Good sanitation should be the first step attempted before grabbing for a can of pesticide. This includes sealing garbage in air tight bags but also rinsing soda or food cans before adding them to the recycling bin, removing insect, diseased or bird damaged fruit from backyard fruit plants, and limiting outside feeding of pets.
Adding barriers can be as simple as caulking gaps around windows or doors or where pieces of siding meet. Filling holes in the ground left by decaying roots or stumps will also prevent access to potential nesting areas. Expandable foam calking can be sprayed into voids in retaining walls.
Traps are another method of reducing but probably not or eliminating colonies of yellow jackets. Traps will not provide 100 percent control but they are one tool for limiting numbers during short special events such as picnics and garden parties.
Traps can be store bought or homemade. A simple trap may be made by filling a coffee can 3/4 full of water, and adding enough cooking oil to cover the water (1/4 to 1/2 inch is adequate). The trap is baited with a piece of ripe fruit (apple, pear) by piercing the bait with a stiff wire or slender stick, and placing this such that the fruit is toward the center of the top of the can. The yellow jackets will, in their attempts to get to the bait, fall into the water-oil mixture, and drown. (The oil layer retards evaporation of the water, and also tends to clog the spiracles of the insects). Trapping is most effective in late fall. Locate traps away from the areas you want to protect so the pests are attracted away from activities.
The best control method is the use of insecticides however; effective chemical control is based on locating the nest. If you cannot find the nest, then don’t waste your money on chemical applications.
When treating nesting areas take precautions and dress appropriately. Wear a long sleeve shirt and pull your socks up over your pant legs. The best time to treat the nest areas is around sunset when the yellow jackets have returned and they are least active.
Purchase one to two cans of an aerosol spray that is labeled for wasps and hornets. These premixed sprays should have nozzles designed for application from a safe distance away (about 15 to 20 feet). Most of these aerosols contain pyrethrins or pyrethrin derivatives which are quick knock- down chemicals with low mammalian toxicity.
Spray the aerosol around the opening to knock down any yellow jackets guarding the nest. Then you can use the rest of the can, by spraying it into the nesting cavity or you can apply an insecticidal dust (Sevin) in and around the opening. Dusts are effective when located in areas where they come in direct contact with the adult insects but they are not quick acting like aerosol sprays. If you can’t find a nest put out a saucer of soda or Kool-Aid and follow visiting yellow jackets back to their hive.
Britt West is the extension agent for Barrow County. You can reach him at firstname.lastname@example.org.