Yellow Jackets: The Picnic Pest

Yellow jackets are predatory and persistent wasps, responsible for nearly 50 percent of stings. They often sting when they feel threatened, or when they sense that their nest is in danger. They are social wasps, living in colonies, unlike solitary wasps such as mud daubers and cicada killers. These social insects contain queens, workers (females only), and males (also known as “drones”). In the summertime, yellow jackets become more of a problem on hot, dry days, when they are most active and numerous in number. They can be especially dangerous to those who are allergic to their stings.

Yellow Jacket
Yellow Jacket

Among the different types of yellow jackets are the Eastern Yellow Jacket, the Western Yellow Jacket, and the German Wasp. While there are many different species of yellowjackets in the United States, most have bright yellow (sometimes white) and black stripes on their abdomens and are not as hairy like bees. They are usually ½ inch (12 mm) long, while the queens are slightly longer, about 18 mm long.

Early in the year, a fertilized queen emerges from a site where she has overwintered and looks for a suitable place to build a nest. She builds a nest and lays a batch of eggs, and then seeks insects, providing food for the young after they hatch. As the year goes on, more and more yellow jackets hatch, as the nest reaches its peak population in autumn.

Yellow jackets build nests made of wood fibers. They build nests in the ground, in stumps, and sometimes inside walls and attics, where they can be a threat to humans.

Control of Yellow Jackets

Controlling yellow jackets is easier earlier in the year because only mated queens survive the winter. Therefore, there are much fewer yellow jackets in the spring. If a nest can be located earlier in the year, control is easier.

When controlling a nest, should a homeowner wish to eliminate the nest, he or she can purchase a quick knock-down insecticide specifically labeled for yellow jackets. As always, follow all label instructions, as required by law. While it has been advised to kill yellow jackets in the late evening or early morning hours, note that yellow jackets are not necessarily dormant in the dark hours of the night and are easily stirred. If the nest is above ground, insecticides that shoot several feet into the air can be used.

    • Pest Control Professionals can eliminate yellow jackets in a single application safely and effectively. When nests are found in walls or near the foundation of the home, a pest control operator should be employed to handle the problem. Note that restricted use pesticides can be applied only by licensed pest control operators.
    • Should yellow jackets be encountered when picnicking, removing garbage and refuse in the area will help prevent them from becoming a problem. Covering food and beverage containers may help discourage them as well.
    • Traps can be used to draw yellow jackets away from people, but the trap’s effect is limited, as the traps catch only a limited number.

Other facts about yellow jackets:

  • Can sting multiple times.
  • Only the female has a stinger.
  • The Eastern Yellow Jacket can have up to 5,000 members in its colony.
  • Can be beneficial in that they will kill other insects, including bees, ants, crickets, grasshoppers, and crop pests.
  • They are also beneficial in that they pollinate plants.
  • Also feed on nectar, sugar, carbohydrates and fruit.
  • Will scavenge for meat and sweet items, making them a true “picnic pest.”