Cicada Killer Wasps

I realize that not everyone will have this unique problem, unlike how most of us can have brownpatch, but I thought it would be kind of cool to talk to you about one of the more unique questions I get on GardenLine. It concerns the Cicada Killer Wasp. The question, usually comes to me in this sort of form: "Randy, there's this larger than normal wasp/bee hovering over my lawn, and when I looked closer he burrow himself in a hole about an inch wide…." Then, of course, come the proverbial "how do I kill it" questions.

First, I want you to know that in almost all cases, there is no need to kill a Cicada Killer. Second, the reason it's called a Cicada Killer is because of what it does to the Cicadas. For those who don't know, those are the little boogers that are more frequently heard than seen. And they are often misidentified as Locusts. Cicadas are the critters responsible for that cacophonous, screeching noise during hot, late-summer afternoons. By the way, only the males sing. For more on Cicadas themselves, click here.

Back to the Cicada Killer: The cicada killer wasps attract attention due to their large size, the burrows that they dig in home lawns, and their buzzing flights over the lawn. These insects occur in all states east of the Rocky Mountains and prefer to dig their burrows in sandy, bare, well drained soil exposed to full sunlight. The wasps feed on flower nectar while the immature or larval stage feeds primarily upon cicadas that are brought to the burrow by the adult.

In spite of their large size, the wasps usually ignore people. Yes, they can sting, but only when forced to do so. A mound of fine soil surrounds the burrow of each cicada killer. Since colonies of burrows are common, infested lawns usually contain several mounds that can smother the grass. However, they prefer to nest in areas of sparse vegetation, and rarely infest thick, vigorous turf. (Translation: If you don't want 'em in your yard, follow my fertilization schedule.)

Cicada killers over-winter as larvae in the soil. Pupation occurs in the spring and the adult emerges in mid-June to early July. Emergence continues throughout the summer. Females feed, mate, and dig burrows for several weeks before preying on cicadas. Excess soil thrown out of the burrow forms a regular, U-shaped mound at the entrance.

The females search tree trunks and lower limbs for cicadas. The wasp stings its prey, turns the victim on its back, straddles it, and drags it or glides with it to the burrow. Each cell is furnished with at least one cicada (sometimes two or three) and a single egg before being sealed off. Two to 3 days later the egg hatches. Depending on the number of cicadas in its cell, the larva feeds for 4 to 10 days until only the cicada's outer shell remains. During the fall, the larva spins a silken case, shrinks, and prepares to over-winter. Only one generation occurs each year.

For those people who just can't stand the idea of any kind of wasp buzzing around their property, they may be interested in some kind of control measure. Well, you know the first way - prevent them with a healthy lawn. Even though, as I suggested, they aren't aggressive towards stinging humans, if you need to spray something any of the wasp/hornet/yellow jacket sprays will work. Most of those can be sprayed from a safe distance and a jet of some synthetic Pyrethroid is sprayed.