Wasps as large as hummingbirds? We have had several calls to the hotline about a large digging wasp that creates holes in the ground and displaces large amounts of soil or sand. This is Sphecius speciosus, commonly called the “cicada killer” for the fact that it kills cicadas to provide for their young. Female cicada killer wasps sting a cicada in the air, which paralyzes it. They then lay an egg in the cicada and place it in a nest in the ground where the immature will develop. They prefer well- drained, light-textured soils in full sunlight that are near trees harboring cicadas.
This wasp is active from mid-July to late September in our area, coinciding with the presence of annual or dog-day cicada. The wasps form solitary nests; they do not form colonies. Males will aggressively defend their territory and can be very frightening but lack stingers. Females can give a painful sting but typically only do so when handled or threatened. Cicadas are a plant pest, although a minor one, so the cicada killer can be considered a beneficial insect. There are cultural control measures that can be helpful which consist of
eliminating the bare patches that the wasps use to form their nests. Watering these areas heavily can also cause wasps to abandon their nests.
Cicada killer wasps can be particularly problematic in playgrounds, sand traps, or parks and sometimes make an unsightly mess of lawns. NC State has photos and additional information:
If necessary, permethrin dusts can be applied directly to the holes. It will cling to the body of the female wasp as she enters and exits nests and be ingested when she cleans herself. As always, use pesticides with caution and according to manufacturer’s instructions. The University of Kentucky has more information here: