How to tell you have them
Look for a steady stream of black and yellow wasps flying in and out of one spot: a hole in the lawn, a gap in the siding, a crack in a block wall or a hollow under a shrub. In Florida the southern yellow jacket is the usual species. Yellow jackets are shorter and stockier than paper wasps and fly fast and straight. Later in summer they also show up at trash cans and sweet drinks.
What they damage
Yellow jackets sting repeatedly when the nest is disturbed, and lawn mowers and string trimmers are the usual trigger. A nest inside a wall can grow large enough to chew through the drywall into a room. Anyone who reacts badly to stings should keep their prescribed medication close and call 911 for trouble breathing.
What treatment looks like
We treat yellow jacket nests in the evening, when the workers are home and calm, by applying a dust or another labeled product into the nest entrance. Wall nests are treated through the entrance and left to finish before the hole is sealed. Never plug or caulk an entrance yourself: trapped yellow jackets look for another way out, and that way is often into the house.
How long it takes
Activity at the entrance usually stops within a day or two. We seal wall entrances and remove ground nests a few days later, when nothing is flying.
Florida notes
In our seasonal model yellow jacket activity peaks in September, when colonies are largest and food is scarce. In the warmest parts of Florida a colony can survive the winter and keep growing, so a nest that has been there a while deserves a professional. Yellow jacket nests are covered on every plan, starting with Quarterly.