Yellowjackets can be menacing but they are also voracious predators of insect pests.

With their potent sting, yellowjackets can be menacing creatures when it comes to a showdown over the picnic table. In years when the spring is warm and dry, yellow-jacket populations can increase to the point of making outdoor activities difficult. But few people are aware that yellow-jackets are voracious predators of insect pests such as caterpillars and flies.

Yellowjackets are a type of wasp but they are often mistaken for bees. Sometimes they are confused with other less aggressive predatory wasps, especially paper wasps. Yellowjackets are relatively short and stout compared to paper wasps. Paper wasps have longer more slender bodies and long dangling legs. Yellowjacket nests are spherical and are enclosed in a papery envelope with a small entrance hole at the bottom. Paper wasp nests are usually suspended from eaves or porch ceilings and look like tiny umbrellas filled with hexagonal cells.

Removing an Individual Yellow-jacket from Inside the House

If you are not hypersensitive to yellowjacket stings:

• don’t aggravate the yellowjacket by swatting at it,
• wait until it lands on a flat surface,
• place a glass or plastic container over the insect,
• slide a stiff piece of paper under the opening of the container, and
• seal the container and place it in the freezer overnight to kill the yellowjacket or take it outside and release the insect.

Destroying Nests

Because of the danger of multiple stings, we strongly recommend calling your local vector control district or a private company for information and assistance.

Yellowjackets build nests in abandoned rodent burrows and other holes in the ground, in attics, in wall voids, in shrubs and trees. Sometimes they hang their nests from eaves.

Trapping Yellowjackets

Traps can provide some relief from yellowjackets, however individual yellowjackets can sometimes escape traps. There are a number of traps on the market, some disposable and others reusable. Experiment to find the trap or traps that work best for you.

• Follow label directions for setting traps, disposing of trapped yellow-jackets, and cleaning and reusing traps that are reusable.
• Place a number of the traps around the periphery of your yard or picnic area to lure the yellowjackets away from your activities and food.
• Set the traps out a few hours before bringing food outdoors so the insects change their foraging patterns.
• If one of the traps is not attracting yellowjackets, move it. If you set out several traps and none of them are attracting yellowjackets even though they are present, try changing the bait. Use baits such as tuna-flavored cat food in the spring and early summer. Try using grenadine or the attractants that come with the traps in late summer and fall.

Poison Baiting

As a last resort in years when yellow-jacket populations are extremely high, poison baiting may be necessary. Call a pest control professional.

Yellowjackets seldom sting when they are foraging for food, unless they feel threatened. They are, however, likely to attack when their nests are disturbed by a direct blow or by vibrations that are detected by the wasps inside. Mowing the lawn near an underground nest, construction work near a nest in a wall void, or even walking near a nest can provoke an attack by one or more yellowjackets. This is especially true if the nest has been disturbed before.

When a yellowjacket approaches:

• Remain calm
• Do not strike at a yellowjacket with sharp, sudden blows. Slow, gentle motions that mimic the movement of a branch in the breeze will be safer in encouraging the yellowjacket to leave.
• You can brush the yellowjacket off with a piece of paper or some other object as long as you move slowly and deliberately.
• Do not squash a yellowjacket. When crushed, many yellowjacket species emit a chemical that can cause other nearby yellowjackets to attack.

• Wear protective clothing when mowing grass where you suspect underground nests.
• If you are hypersensitive to yellow-jacket stings, avoid outdoor cooking or eating. Hypersensitive people should wear clothing that covers as much skin as possible, and carry an epinephrine kit (available by prescription) at all times.
• Outdoors, do not drink soft drinks or other sugary drinks from open containers. Use cups with lids and straws, and look before you sip. Do not carry snacks containing meat or sugar in open containers.
• Do not wear perfumes. Use unscented deodorant, sun screen, hair spray, etc.
• Avoid going barefoot, especially in vegetation.
• Always examine wet towels or wet clothing before you pick them up outdoors.
• Wear light-colored clothing without patterns.

Examples of trade names for products listed in this fact sheet

Traps:

• Rescue! Yellowjacket (disposable)
• Rescue! Trap (reusable)
• Surefire® Deluxe Yellowjacket and Wasp Trap
• Victor® Yellowjacket and Flying Insect Trap

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