A Wasp on Steroids? 

Last week I walked into a wasp nest – both figuratively and literally.  A local pest control business brought in several dead wasps that were collected from the courtyard of Raulerson Hospital.  The report was that these critters were BIG, and they were flying around and scaring the hospital staff, guests and patients. 

When I went on-site to investigate, I arrived to a "bee-hive" of activity.  The hospital staff was involved in a mock-disaster drill, and yours truly was declared “contaminated.”  While I was inadvertently volunteering to be a victim, I had a chance to get reacquainted with Gina Ward, one of our local Master Gardeners and member of the hospital staff.  After being officially cleared, Gina directed me to one of their courtyards.  

I discovered what the buzz was all about: I counted at least 30 hills of wasp nests and many more yellow and black wasps flying among the trees and shrubs. These were big "bugs" – more than an inch long, with bodies as wide as a bumble bee.  But it was not scary at all – I felt secure that I was not going to get stung, as this was a colony of the beneficial Cicada Killer Wasp – the subject of this week’s column.

While most wasps and bees should be taken seriously, this is one that may seem intimidating because of its size.  Experiences with the Cicada Killer Wasp have shown it to be generally harmless-  unless you happen to be a cicada.  These wasps make solitary nests in the ground that look like oversized anthills.  The adult wasps then fly out to find cicadas, which are paralyzed by a sting and then brought back to the hole in the ground.  In the underground nest, the cicada serves as food for the developing wasps.

There have been two different species of cicada killer wasps found in Florida, and the most common one is mostly black in color.  It has three pale yellow bands that only go partially around the fat abdomen.  The legs and eyes are a rust color, and there is a similar colored spot on the back between the 4 amber-colored wings.  Males are a bit smaller than females, but are more commonly seen flying around the colony.

While this insect may be sometimes called a Ground Hornet, according to Purdue Extension Educator Steve Mayer some people refer to this large docile wasp with a less fearful name of Cicada Hawk.

Cicadas are fairly large insects in their own right.  They measure about two inches long and a half inch in diameter.  In the heat of spring and summer days, you may hear a slowly accelerating song of repeated “che-che-che” noises made by the male cicadas. [ Here's my article on cicadas, and click here to download audio files of cicada songs.] The adult cicadas emerge from the ground after several years of feeding on the roots of trees to mate, and their size makes them a substantial meal for the cicada killer larva.

Cicada killers over-winter as larvae in the soil.  Warmer spring temperatures bring on the pupation of the wasps in the ground, and emergence of cicada as food.  Florida sees both wasps and cicadas emerge earlier than in other parts of the country.

In public places, this wasp can be viewed as a nuisance. Those people known to have severe reactions to other kinds of bee and wasp stings will not want them around.  However, the severity of their sting is reported to be very mild when compared to the sting of other bees and wasps.  And, while the slightly smaller male wasps are more likely to be flying abound a person, they do not sting.  The female has the stinger, and the reports are that they will only use their stinger if trapped in clothing or captured in a fist.

Cicada killer wasp colonies, called “leks” by Prof. Chuck Holliday of Lafayette College, are often found in disturbed areas (i.e. near buildings and structures) that are neglected (i.e. with minimal landscape maintenance). Other characteristics of nests are that they face south, have well drained soil, and are nearby trees (which will support the cicada populations).

Knowing what conditions create a wasp colony will give some clues to non-chemical management of unwanted cicada killer wasps: provide regular irrigation and maintenance to encourage vegetation to cover the soil.  Flooding the wasps out with a hose or with a drench of soapy water is another idea - this will discourage wasp nesting. The suggestion that mulching will discourage nesting has been made; however, the colony I observed was thinly mulched, and offered little discouragement.

University of Florida entomologists have some chemical pesticide recommendations [See table 7] for outdoor wasp control, but be sure that you are using a properly labeled product and are indeed dealing with a cicada killer wasp.  Other more dangerous ground-dwelling yellow jackets and hornets can be much more dangerous for homeowners to attempt control.  Contact our office for specific pesticide recommendations or assistance with identifying this insect

I’ve placed more information on our Okeechobee web page,  http://okeechobee.ifas.ufl.edu.  If you would like to see some additional references on scorpions, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners on Tuesday afternoons from 1 to 5 PM.  

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Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.  Florida Cooperative Extension Service / IFAS / University of Florida.  Millie Ferrer, Interim Dean  Last update: 06/21/2010 .  This page is maintained by Dan Culbert 

references

Culbert, D.F. "Beware a Plague of Locusts". Okeechobee News, 5/31/2004. http://okeechobee.ifas.ufl.edu/News%20columns/Locusts.htm 

Koehler,  P. G. and Oi,   F. M. Stinging or Venomous Insects and Related Pests.   ENY-215   Gainesville:  Florida Cooperative Extension Service,  March 2003. http://edis.ifas.ufl.edu/IG099

Holliday, Charles W.  Prof. Chuck Holliday's Cicada-Killer Page  Easton, PA: Lafayette College, 1998-2005.   Detailed information on the biology and habits of this wasp, with suggestions for management , complete with photos, drawings, movies, etc. http://ww2.lafayette.edu/~hollidac/cicadakillerhome.html

Stange, Lionel A.  The Cicada Killers of Florida (Entomology Circular No. 402).  Gainsville: Fla. Dept. Agriculture & Consumer Services, Division of Plant Industry, September/October 2000 http://www.doacs.state.fl.us/pi/enpp/ento/entcirc/Entcirc402.pdf .  Also published as UF/IFAS publication EENY-295 (Featured Creatures Bulletin) Publication Date: June 2003. http://creatures.ifas.ufl.edu/beneficial/cicada_killers.htm.

Cicada Killer Wasp Extension bulletins from other states:

•   Indiana (Purdue) http://www.entm.purdue.edu/Entomology/ext/targets/e-series/EseriesPDF/E-63.pdf

• Iowa : http://www.ipm.iastate.edu/ipm/iiin/bdigwas.html

• Kentucky : http://www.uky.edu/Agriculture/Entomology/entfacts/misc/ef004.htm

• Nebraska (photos) http://entomology.unl.edu/images/cicadakiller/cicadakiller.htm

•   New York/Nassau County http://www.ccenassau.org/hort/fact_sheets/e106_cicadas_jan02.pdf 

• North Carolina : http://www.ces.ncsu.edu/depts/ent/notes/O&T/lawn/note63/note63.html

• Ohio : http://ohioline.osu.edu/hyg-fact/2000/2078A.html

• Oklahoma : http://www.ento.okstate.edu/ddd/insects/cicadakiller.htm

•   Texas : http://insects.tamu.edu/fieldguide/cimg331.html

Images

• Some nice close-up pictures of cicada killer wasps by Vergil Bushnell - http://www.vergil.net/Pix/Insects/cicadakiller.html

• A beautiful drawing of a cicada killer wasp by David Hruby  http://hrubydesign.com/pages/Hruby-CicadaWasp.html