For Release August 20, 2006

Hornets from Hades

AGRI-VIEWS by Chuck Otte, Geary County Extension Agent

            There is a member of the wasp family that is being seen around the area this summer that is, understandably, causing some concern. In reality, this giant hornet looking critter can attain lengths of nearly one and three quarters inches, but if you ask someone who has them in their yard, they will tell you that they look like about three times that big! This giant wasp is called a Cicada Killer. While they can look, and sometimes act, very threatening, they are rarely a threat to people.

            Like all members of the bee and wasp family, only the female cicada killer is equipped with a stinger. Unlike many other bees and wasps that we are familiar with, bumblebees, yellow jackets, honeybees, etc., cicada killers do not normally use their sting defensively, they use it to paralyze their prey. Unless you really torment a cicada killer, she won’t sting you and will generally leave you alone. The males have no stingers, but keep in mind that both sexes of these large wasps do have powerful jaws and they can inflict a noticeable bite if bothered.

            Cicada killer females are the ones that do all the work. They dig a hole in nice, well drained soil, often in flower beds, along sidewalks or driveways or around shrubbery. This hole can easily be an inch in diameter and is usually surrounded by a nice pile of finely ground dirt. Cicada killers are solitary nesters, they don’t form colonies. The female goes out and finds a cicada which she attacks and stings. There is a brief struggle as the venom paralyzes the cicada. During this time the cicada and cicada killer usually tumble to the ground. She then has to drag the cicada up a tree or pole to gain enough altitude so that she can fly/coast back to her nest site.

            Once back to the nest hole, she pulls the paralyzed cicada into the tunnel, arranges it in the tunnel and lays an egg on it. Each egg then hatches out and has all the food it needs to complete its life cycle. The larvae overwinters in a hard cocoon that it weaves, and then pupates in the spring. It’s emergence as an adult is delayed until mid summer to coincide with peak emergence and activity of the cicadas.

            The males, on the other hand, aren’t worried about digging nest tunnels or finding food to put in that tunnel to provide food for that young cicada killer. They only have two things on their minds. The first is to be present to mate with any recently emerged females. Coming in a distant second, is food; pollen and nectar from flowers. The males will patrol an area and defend it aggressively to keep other males from coming into their territory to mate with the females.

            Control is usually not necessary or practical. You can use wasp and hornet killers in the nesting holes or liberal sprinkle carbaryl (Sevin) dust into the nesting hole. But this will only control, maybe, the females. The males are the ones that you see constantly flying around. The males never go near the nest holes and will be unaffected by the insecticide. We are probably right at the peak number of cicada killers now and the numbers will start to fall rapidly as we move into September. Treating for cicada killers now will do little to reduce the numbers next year.

            The number of cicada killers has increased noticeably in recent years, as have the phone calls to my office about this insect. Try to ignore them and be aware that they will only be around for a fairly short time. Then also remember that they act much more threatening than they really are!

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