Because of the annoying habits of a certain pest in Robeson County, at the last minute I have changed the topic of this column in order to provide our readers with some interesting information. The topics of these columns are often determined by an unusually large number of phone calls or office visits related to certain pests, which indicates a need to share information about these pests with more people.

Quite a few people have called our office during the past two weeks, and several people have come into our office carrying a jar in their hands, each asking about "great big yellow and black wasps" that are flying several feet off the ground in their yard. Because of the size of these wasps, most people are terrified that they or one of their children will be stung.

The wasp causing all the concern is the "cicada killer wasp," a fairly common insect in Robeson County. Although this wasp looks very threatening because of its size, it is usually docile and harmless. Although it is probably capable of inflicting a painful sting if handled, the cicada killer wasp is usually difficult to provoke. Mating males appear to be aggressive and more easily disturbed, but like all other wasps and bees, the males cannot sting.

Cicada killer wasps are solitary, ground-nesting wasps. They do not build nests with hundreds or thousands of other wasps, but instead, seek out a suitable site in sandy, well- drained soil to dig a burrow. If the site is very desirable, there may be several, or even several dozen, other cicada killer wasps that have chosen the same area, but each wasp is digging its own individual burrow. When several large wasps start flying around someone's yard, naturally, they are going to become concerned.

These wasps usually prefer to nest in areas of sparse vegetation, so they rarely infest lawns with thick, vigorous turf. When they do select a site and start burrowing, they deposit rather large mounds of soil around the burrow. In well- kept lawns, these mounds of soil are often more annoying than the wasps.

The cicada killer wasp does not feed on plants. Adult wasps feed on the nectar of flowers. They do, however, catch and sting adult cicadas and carry these cicadas back to their burrow to serve as food for their larvae during development.

Once burrows have been constructed, the search for cicadas begins. Canvasing tree trunks and lower limbs, the wasp locates and stings a cicada. The sting does not kill the cicada, it only paralyzes it. The wasp then turns its victim on its back, straddles it, and drags it or glides with it back to the burrow. Each cell in the burrow is furnished with at least one cicada, but often as many as two or three, and a single egg before being sealed off.

Two to three days later the egg hatches. Depending on the number of cicadas in its cell, the larva feeds for four to ten days until only the cicadas' outer skin remains. During the fall, the larva spins a silken case, shrinks, and prepares to overwinter. The following spring the larva pupates, then emerges from the soil as an adult during the summer, and the cycle starts all over again.

In southeastern North Carolina, these wasps usually emerge from the soil about the first week of July. This emergence is timed with the emergence of the cicadas, since cicadas serve as the food source for the larva. These wasps will remain active for about one month, about the same period of time that the cicadas are active. There is only one generation per year.

Since these wasps feed on the annoying cicadas, they are generally considered beneficial insects. Since they do not sting, trying to control them is not encouraged unless they are causing unsightly damage to a lawn.

If control is necessary, chemicals may not be a preferred practice, because it may be difficult to effectively treat individual mounds. Since these wasps hover close to the ground and are so docile, the old tennis racket or short boat paddle method is often very effective. Your neighbors may wonder why you are standing in the front yard wildly swinging in the air, but with very little effort, you can eliminate this very common pest.

For more information about cicada killer wasps or other pests around the yard, give us a call.

E-mail address: Everett_Davis@ncsu.edu

Mailing Address:
P. O. Box 2280
Lumberton, NC 28359-2280

Phone: 910-671-3276
Fax: 910-671-6278

Date Created 09/13/01