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Extension > Yard and Garden News > Cicada killers common now

Friday, August 4, 2017

Cicada killers common now

Jeffrey Hahn, University of Minnesota Extension

A large solitary wasp called a cicada killer, Sphecius speciosus, is common in many areas of Minnesota now. It ranges in size from 1 – 1 ½ inches long. It has a black abdomen with yellow bands, a reddish brown thorax with reddish brown legs and amber colored wings.
Cicada killer with a captured cicada.  Jeff Hahn, U of M Ext.

Some people mistakenly believe they have found a European hornet which is also a large wasp. However, European hornets are social insects living in nests they usually build in tree cavities; they can also be found within homes and other buildings. European hornets do not occur in Minnesota.

Cicada killers nest in the ground, typically in well-drained, light soil exposed to full sun. They are a solitary wasp, meaning that there is only one wasp per burrow. However, cicada killers are gregarious, so there are typically many of them in a small area.

These wasps prey on cicadas. Cicadas are stout, winged insects that are common during the summer. A cicada killer uses her stinger to paralyze a cicada she captures. She carries it back to her nest where it is food for her young. Once the larvae are full grown, they pupate and remain in their burrows until next year.                    

Despite their size, cicada killers are not dangerous to people. Females have stingers but they are not aggressive and ignore people. They do not have an instinct to protect their nests (like yellowjackets and honey bees) and you can walk among them with little worry. Of course, if you provoke a cicada killer or it feels threatened, it can sting to protect itself.
Cicada killer nests can become very abundant in a small area. 
Jeff Hahn, University of Minnesota Extension

Fortunately, cicada killers are just annoying. Their tunneling can be unsightly but does not kill lawns. It is not impossible for their burrowing activity to undermine patio bricks but that is not common.

If you have cicada killers nesting on your property, there are a couple of options to consider. The first is to ignore and tolerate them and let them run their course. Remember, there is very little risk of stings and they will go away on their by the end of the summer. The area can be roped off, in necessary, to keep people away from the nests.

Another option is to treat the nests. Treating the general area is not very effective. Instead, apply an insecticide into each individual nest entrance. Dusts are most effective, although sprays can help reduce numbers. Be sure the product you use is labeled for you use on turf. Effective active ingredients include permethrin and carbaryl. You can also hire a lawn care company to treat the cicada killers.

2 comments:

  1. Great article as always. But I feel I have to comment on how the final thoughts left me again feeling a little uncomfortable. I always seem to cringe at the common "best practice" in Extension publications of suggesting the use of pesticides as a "normal" or equally valid option of IPM. Especially for beneficial native or naturalized species. (WIKIPEDIA: "Cicada killers exert a measure of natural control on cicada populations and thus may directly benefit the deciduous trees upon which their cicada prey feed".)

    I do realize its important for reasons of objectivity to provide this extermination option to the public, so it has to be covered - but maybe the ending thought of articles like this could instead try to reinforce the beneficial role of the species in the natural order of things?

    ReplyDelete
    Replies
    1. Thanks for your comments Christopher. I will keep that in mind the next time I write about cicada killers.

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