RAP SHEET

Yellow Jacket

Vespula spp. / Dolichovespula spp.

moderate CASE #MWP-0010

Stung three people at a Labor Day cookout. Still defending the potato salad.

How We Take Them Down

  1. Nighttime insecticide treatment directly into nest entrance when colony is inactive
  2. Residual dust application into wall void or underground nest openings
  3. Full foam expansion treatment to fill wall voids housing aerial nests
  4. Nest removal after confirmed elimination of the colony
  5. Perimeter treatment in late summer to reduce forager activity near entry points

Prevention Tips

  • Inspect the property perimeter in early summer for small, active entry holes in the ground or siding
  • Keep outdoor food covered and clean up spills immediately at cookouts
  • Use tight-fitting lids on outdoor garbage cans — yellow jackets love food waste
  • Seal gaps in siding, soffits, and around utility penetrations before summer
  • Never swat at a yellow jacket near a nest — the alarm pheromone release makes a bad situation much worse

Fun Facts

A single yellow jacket nest can house up to 5,000 workers by late summer. All of them can sting. All of them will.

Unlike honeybees, yellow jackets have no barbed stinger, so they can sting the same target multiple times. They find this feature very useful.

Yellow jackets are technically beneficial predators early in the season — they feed larvae on caterpillars and flies. By August, they've pivoted to your hot dog and they're not pivoting back.

The queen is the only colony member who overwinters. She starts a new nest alone each spring. Every large nest you see started as one insect and a very ambitious attitude.

Field Notes

Yellow jackets are the pest that turns a pleasant August afternoon into an emergency room visit, and they have a particular talent for building nests exactly where people walk, sit, or mow. Unlike bees, they’re not passive — by late summer, when colony populations peak and natural food sources decline, yellow jackets become aggressively territorial and will pursue a perceived threat far from the nest. The underground and wall-void nests are especially dangerous because they’re frequently discovered by accident: a lawnmower passes over an entrance hole, someone leans against a wall, or a door is slammed too hard. If you find a nest, do not attempt to treat it during the day, and do not seal the entrance without treatment.