Late July is generally the month when insects and other pests flourish in our landscapes. Some have expressed concern about giant “hornets” buzzing them and digging in their lawns. Cicada killer wasps are very large hornet-like bees that would seem to pose an immediate threat, especially to those allergic to bee stings or with small children. However, these large, slow flying wasps are not aggressive like yellow jackets, hornets or wasps. They tend to be very curious and protective buzzing people as they walk through their lawns and gardens.

Cicada killer females use their sting and paralyze cicadas and feed them to their young. Cicada killer grubs hatch in mid-July above ground for 2-6 weeks; all adults die annually.

Cicada killers can be controlled with Sevin dust or liquid near each nest entrance. Be careful not to disturb the burrow as the female must walk through the dust for control. You may need to repeat treatments for 2-3 weeks if new wasps move into the area. At close range, adults can be killed with a wasp aerosol as they light on foliage or enter the nest burrow. Before using any insecticide, always read the label directions to confirm current listing of pests, and follow safety precautions.

Another way to prevent cicada killer nesting is to plant dense, tall vegetation or mow your lawn at the highest setting during the nesting period. In shrub and flower beds make sure you have a three-inch layer of mulch.

The wasps don’t live very long, so at most they will be a pest about two months out of the year. Go to https://content.ces.ncsu.edu/cicada-killer-wasp for more detailed information.

Darrell Blackwelder is the retired horticulture agent and director with the North Carolina Cooperative Extension Service in Rowan County. Contact him at deblackw@ncsu.edu.