Giant Hornets

June 30, 2008 | By | Comments (15)

Q: Every July, huge hornets bore holes in my flower garden. They really make a large pile of dirt beside the hole. What can I do?

A: From your description, I’m guessing the hornets in question are cicada-killers. These very large wasps (up to 2 inches long) are identified by their black to reddish-brown abdomen with light-yellow stripes. They are solitary, not social like paper wasps, and dig individual burrows to rear their young. They get their name from their habit of paralyzing cicadas with their sting, then dragging the insects into the burrows to feed their young. Cicada-killers are usually not aggressive, but if one stings you, it’ll knock you down. To get rid of them, sprinkle Sevin dust around the entrance to their burrows at night. As they leave and enter the burrows, they’ll get the dust on them and spread it to their young, killing them all.

COMMENTS

  1. Wanda Turner

    When is a good time to trim my oak leaf hydrangea? It is now in mostly shade and has a lot of blooms. I use pine needles and thick layers of news paper to mulch it.

    June 30, 2008 at 9:01 pm
  2. Grumpy

    Whenever you go to prune an oakleaf hydrangea, the first thing to check is whether it’s surrounded by giant hornets. If it is, go watch Oprah for a while (although depending on the subject that day, watching Oprah might be more painful). Absent the hornets, the best time to prune an oakleaf hydrangea (Hydrangea quercifolia) is immediately after it finishes blooming in spring and early summer. This is because it blooms on growth made the previous year. If you prune it anytime from midsummer through winter, you risk cutting off the flower buds for the following spring. So if you need to prune yours, don’t wait — do it right away. Grumpy

    July 1, 2008 at 1:16 pm
  3. John C

    Since cicadas have such a long life cycle I imagine that those hornets will keep coming back. I thought I had it bad with some bees! Those hornets are freaky huge. Their sting has to be awfully bad.

    July 5, 2008 at 9:27 am
  4. Grumpy

    It’s nearly as painful as watching women’s basketball on TV.

    July 15, 2008 at 7:12 pm
  5. melissa

    Summer of 2007, I lived in a house that had a fruit tree in the back yard. That year the tree was attacked by thousands of very large black and yellow wasps. Very similar to the ones in ‘Giant Wasps’ The looked like the big asian ones! No spray could kill them and keep them from coming back. We didn’t get a single pear from that tree. These wasp were very aggressive, and would attack our porch lights at night and try to get into our house. I don’t know what they were, but I’d never seeen a hornet as large as that or aggressive before. What could they be?

    July 18, 2008 at 5:52 am
  6. Grumpy

    It sounds like the European giant hornet, which is the largest and surliest wasp in North America. It usually nests inside tree cavities and strips bark off of lilacs and other trees and shrubs to make its nests. It is very aggressive and will attack without provocation. The Grump had the privilege of being stung by one many years ago. Felt like a needle full of napalm. All of the wasps in a nest die in winter except the queen. So if you find the cavity and spray it then with wasp & hornet killer, you may avoid a repeat performance.

    July 18, 2008 at 7:41 am
  7. Pamela White

    About 5 nights ago I killed 2 “monster” hornets. Two nights later, 7. Last night we killed 14 of them! They come in on the porch at night, whether the light is on or not. I used to hear them referred to as “mountain hornets”. Lately, three people have told me they’re Japanese Hornets. According to research I’ve done, they could be European Giant Hornets. They’re 1.25-1.5 inches long. Why are there so many of them out here? Is this an indication that there is a nest really close? They worry me. We’ve only been seeing them the past week. Are we stuck with them until winter? HELP!

    August 24, 2008 at 2:51 pm
  8. Grumpy

    Pamela,
    It sounds to like you have a nest of European giant hornets either near your home or actually somewhere in it. Usually, they nest in tree cavities, but they can also nest in crawl spaces, wall voids, and attics. They are huge and thick-bodied, about 1-1/2 inches long, with abdomens that have yellow and reddish-brown stripes. Unlike most other wasps and hornets, they are active at night. They are extremely aggressive and if they sting you, you will never forget it (I’ve been and I haven’t.) For this reason, I do not recommend dealing with this problem yourself. Call an exterminator, show them the dead hornets, and see what they suggest.
    Here’s a link you might find helpful: http://www.utextension.utk.edu/publications/spfiles/SP290-A.pdf.
    Good luck.
    Grumpy

    August 24, 2008 at 6:52 pm
  9. Tedster

    Was stung by one late last night. Had gotten into the house and was in the curtain. When I tried to close the curtain he got me twice. On the neck and on the big toe, before I could stomp him. Never had such pain from a bee sting or wasp. Lasted all night. Hurt like blazes! 2, 3 hours later it hurt just as bad as when I was first stung. Finally went to sleep exhausted. Ok, this morning, but still hurts a little. Watch out! These are killers!

    September 7, 2008 at 9:17 am
  10. Grumpy

    When I was a kid, my brother got stung in the head by one. Soon, his head was as big as Bill Clinton’s. Later, when I was in college, one got me in the arm just for walking past the lilac bush it was on (these monsters chew off lilac bark and use it to make nests). I thought I had been shot. My arm swelled up to the size of my leg. So if you ever see a European giant hornet, my advice is kill it or run. Grumpy

    September 7, 2008 at 11:15 am
  11. Linus, K.C., Ks

    I had thousands of these in my garden about 15 years ago. Just prior to their appearance thousands of cicadas came out. It scared me at first but I noticed that they were attacking the cicadas so I figured they wouldn’t bother me. I mowed the yard without incident several times plowing right through clouds of buzzing hornets. Not one of them acted like he was interested in me or my lawnmower. I’m not saying they wouldn’t sting but I really think you would have to be making quite a pest of yourself to get stung. And if they did I’m sure the sting would knock you over, it may do more than that. They came back for a couple of years but I haven’t seen them now for about 10 years.

    August 31, 2011 at 9:29 pm
  12. Ross

    Mean Green Orange Fresh cleaner works better than wasp/Hornet Killer and is nontoxic. Good for killing around house, near people. Applied liberally I am convinced it kills them faster than toxic chemically that I have used. I am going to try Sevin around the nests. I have many nests and they are growing on number each year

    September 5, 2011 at 10:35 am
  13. Grumpy Gardener (His Benevolence)

    Ross is right! Orange oil cleaner kills wasps, bees, and roaches just as fast as Raid, and it also cleans and shines your furniture!

    September 7, 2011 at 12:33 pm
  14. newknew

    Giant hornets have attacked my two lilac bushes. I had been thinking of moving the smaller one this fall. Will the lilacs survive the attack?
    There is a pile of hard wood sections nearby that surely hold the queen and the nest. We will have to blanket it to get to the queen.
    Thank you for your insight.

    September 13, 2011 at 8:40 am
  15. Grumpy Gardener (His Benevolence)

    European giant hornets strip the bark of lilacs to make their nests. They can kill a branch or two, but generally don’t kill the plant. They usually make nests in the hollows of trees. BE VERY CAREFUL in attacking them. They are very aggressive, have powerful stings, and will go after you without provocation. The only time I would approach them is at dusk or very early morning with a jet-spray hornet killer. Wear protective clothing and a hat.

    September 15, 2011 at 2:38 pm