For Release July 31, 2001

AGRI-VIEWS
by Chuck Otte, Geary County Extension Agent

I started receiving phone calls about two weeks ago about the hornets. When I think of a hornet, I think of the typical yellowjacket that shows up in late summer and early fall. So when homeowners started talking about lots of hornets I thought it was just a little bit early for this problem to be starting.

When I went out to start investigating this question, and when folks started bringing some of these hornets into the office, I realized that we were seeing an incredible population explosion of the cicada killer. Cicada killers are one of the largest members of the bee and wasp family. They look like a giant wasp or hornet, because they are. They can be well over an inch long and have the classic wasp look. The abdomen is black with two to three yellow stripes. The wings are clear with a bit of a brownish or reddish tinge. A photo of a cicada killer can be viewed on the Internet at: http://www.ink.org/public/kda/phealth/phprot/062090.jpg.

Cicada killers are solitary nesters. They excavate a hole in the ground. These are often found in gardens or flower beds, someplace with bare soil. Occasionally we’ll find them in lawns, especially along a sidewalk or driveway. At the entrance to the hole there is usually a pile of finely ground soil.

The female cicada killer locates a cicada and paralyzes it with it’s powerful stinger. Since the cicada is too big to just fly off with, the cicada killer then must drag the cicada up a tree to gain enough altitude to sort of glide back to its nest. Upon returning to the nest, the cicada killer drags the paralyzed cicada into the tunnel and lays an egg on each cicada. When the egg hatches, it has a ready supply of food. This could be a great subject for a science fiction horror movie!

The good news is that cicada killers are not a big threat to humans. While they are big, and have been known to sting people, they normally won’t. All the cases of human sting victims that I’m aware of are where cicada killers were grabbed or got caught up in clothing. Cicada killers use their sting in an offensive manner. They use it to collect and paralyze food. Honeybees, bumblebees, yellowjackets, etc. use their stings in a defensive manner. They protect their colony with their sting. The toxins in the venom are different for these two groups of bees. Those with defensive stings have toxins to inflict as much pain as possible. Those with offensive stings have toxins to paralyze their prey.

I am not sure why we are having such a population explosion this year. There were a lot of cicadas last year and this. I’m sure that is part, or a lot, of the reason. A contributing factor has to also be that last year and this year seemed to be good years for insects.

While information on cicada killer population explosions is limited we can draw a few conclusions. Some sources indicate that there is just one generation per year. The larvae only feed for about a week before pupating, but they emerge as an adult until the following year. Apparently the emergence of new cicada killers can occur for several weeks, however. While solitary nesting, several females may be working in the same area. There may also be many males in this same area waiting to mate.

If you see a nest hole, you can either use a wasp and hornet spray or spread Sevin dust around the entrance. Adults that are resting or flying can be sprayed with the wasp and hornet sprays. While they appear scary, they should be of little threat. They can be controlled as described, or just left alone and they should go away in a few more weeks!

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