Large Wasp/Hornet – Demise of elm
August 29, 2011  3:44 PM
Dear What’s That Bug,
(I have tried to use the online submission page but was not working very well.  I have a new ID request.)
I have (had, I should say) a “Liberty” Elm tree planted in the yard of the office. In the past two weeks, the tree has folded and has almost given up the ghost.  Since it has a few green leaves left, I will wait till it is finished before I do the autopsy. The insects are having a field day on the tree literately sucking the life out of the tree.  The ants were first to the party but now it has broken out into a  veritable sugar stick attracting all of the resident insect populations.  The giant wasp/hornet was in the 2in+ category and not very aggressive.  I am thinking European Hornet. What does the “What’s that Bug” crew have to say?  Did the hornets cause the holes?  And for bonus points, can someone tell me what is the most likely cause of death of the poor elm?
Thank you,
Jim Kirkland
University of Illinois
Illinois Forest Resource Center
R.R. 1, Box 255
Simpson, IL  62985

Cicada Killer drinks sap from a compromised Elm Tree

Hi Jim,
This has to be one of the most cheerful photos we have ever received of a Cicada Killer.  Even the photos of Cicada Killers with Cicadas are about the Cicada Killer providing for her brood, or in a sense, doing housework.  Here she is just taking a break and enjoying a sweet and nutritious drink.  With enough sugar in her, she will be able to hunt Cicadas for a long time.  We don’t know what is wrong with your elm tree, but we suspect it involves boring larvae, either Pigeon Horntails or Buprestidswe imagine.  Because we don’t know what is eating the trees, we will tag this as a mystery.   Your declining Elm tree is a marvelous study of the web of life that will surround it as it dies.  If you send us future updates, please continue to use the title Demise of Elm.

What's Eating the Elm Tree

Dear Daniel,  Thank you for the reminder, I am sure that at one time I knew that info.  Yes, the scavangers are doing their work, making sure that nothing goes to waste.  The ants were the first, now the party is very interracial and everyone is enjoying the sweet wine at the elm table.  Skippers, ants, wasps and bees, they are all enjoying the sweet smell of demise.  I especially enjoyed your description of a “cheerful” cicada Killer”! Every cicada killer is partying hard this year (especially since this is the year of majicicada emergence). They have  been drunk since the beginning of May when the singing began! This is their party your of good fortune!
Thanks, Jim Kirkland

Hi again Jim,
Since the
Magicicada species emerge periodically in prodigious numbers, they contribute a great deal to the food chain, however, they also emerge in late May and early June, significantly earlier than Cicada Killers, so we don’t believe Cicada Killers benefit from the various broods of 13 Year and 17 Year Cicadas.  That bounty benefits predators that are not species specific in their preferences.


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Location: Illinois

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