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Large wasp-like insects (cicada killers)


Q. We’re seeing very large black and yellow flying insects that look like wasps flying around our yard. They seem to be entering areas with piles of dirt along our walkway. What are they and how do we get rid of them? 

A.The large wasps you’re seeing are called cicada killer wasps (Sphecius speciosus). They are easily identified by their large size — nearly two inches in length. They are very distinctive, with black bodies and yellow stripes. They have large reddish-brown eyes and legs. Wings are reddish-brown and held out from the body during rest.

Cicada killers are solitary insects and most commonly nest in areas with bare soil, along edges of flower beds, on golf courses (especially sand traps), athletic fields, and play areas.They are particularly noticeable along walkways throughout the villages along the lake because of the sandy soil conditions.

Females build burrows underground, displacing 6 to 8 inches of soil. Burrow entrances may be 1 to 1 ½ inches in diameter. Each female creates her own hole in loose, well-drained soil or sand in full sun. They do not nest in colonies as many other wasps do. Females spend the night in their burrows; males rest on shrubs near the burrows. Adult cicada killers emerge July through August. They are short-lived adults, living one to two months after emerging. One new generation is produced per year. Both males and females feed on tree sap and flower nectar. Female wasps strike and stun cicadas in the air, then fly away with the cicada down into the burrow. The female lays one egg on each cicada collected. Eggs hatch into grublike larvae and feed on the hapless cicada. Full-grown larvae overwinter in the burrow and pupate into adults in the spring. These wasps are not aggressive, but are very intimidating because of their large size. Families with young children are often frightened.