Subject: bug and nest material
Location: Rochester, New York
August 7, 2012 1:50 pm
Hi. I keep getting bugs of some kind nesting between wood casement windows and the jambs…a teeny tight space. Sometimes I find clumps of dry grass, other times little dried mud tubes(maybe a different species). I’m amazed they can squeeze in there and can’t figure out what the attraction is. They aren’t damaging the wood, but messy when I open a window that’s been closed for months, and the stuff falls into the room. In today’s cleaning I found actual bugs (a brighter green than the photo shows). Thank you!
Signature: Hiawatha

Grass Carrying Wasp Nest provisioned with Tree Crickets

Dear Hiawatha,
The insects in your photo did not make this nest.  They are what appear to be Tree Crickets and they are the prey of the nest maker, a Grass Carrying Wasp in the genus
Isodontia.  According to BugGuide:  “Larvae are fed Grillidae (particularly tree crickets) or other Orthoptera” and “These wasps commonly make their nest in the narrow track found above outer windows.”  See BugGuide for additional information on the Grass Carrying Wasp.  The mud nests you found were most likely the nests of Mud Dauber Wasps and they are generally provisioned with spiders to feed the larvae.

Grass Carrying Wasp Nest

Wow…thanks, Daniel!  That was a fast response and very comprehensive.  I really appreciate your taking the time to answer.  There’s probably nothing I can do to keep the grass carrying wasps out of the narrow track above the windows, but at least I know what I’m up against.
Again, thanks very much,
Jim Dierks
Rochester, NY

Hi again Jim,
Neither Grass Carrying Wasps nor Mud Daubers are aggressive species and you should not fear getting stung.

Good to know, Daniel.  Thanks.  I’ll just let the little guys do their thing, and with all the other troubles I’ve had with these windows, at least the wasps are just using some convenient space and not harming the windows at all.
Jim Dierks

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Location: New York

22 Responses to Nest of a Grass Carrying Wasp

  1. Vasudha Donnelly says:

    I found a couple of these nests yesterday and cleaned them out. One reappeared today and I took pictures and posted on Facebook. Somebody said they were katydids and, through looking for them, found your site. It’s wonderful when the answers just appear. Thank you!

  2. Veronica says:

    We just cleaned these nests out of 2 storm window tracks and we were thinking they were stink bug nests. Glad to ID the critter finally from you site and others….
    Thank you.

  3. Veronica says:

    PS: We are in Rochester, NY as well -the capital of grass-carrying wasps, I guess !

  4. Jan Caraway says:

    I love watching these little ladies. I have a windchime just outside my kitchen window and enjoy watching her progress. Go girl!

  5. Maria says:

    Apparently these wasps have migrated to Texas, it has been in the high 90’s here.
    We recently replaced all our windows, in one of the frames we found this grassy nest, one solitary wasp flying about as we cleaned off lots of green tree crickets and grass !

  6. Eileen Manion says:

    Is there anything I can use on my window strips to keep these wasps from making a nest? I am thinking of a strong odor type of soap that can be rubbed onto the rubber tracks that will deter these wasps from building a nest. I use my air from early spring into late summer. It is such a chore to clean my screens and window tracks every time I open the windows in the fall. I keep hoping each season I will be surprised and not have to deal with this.
    I am not a fan of any type of insect and hate having to clean this unsightly mess.
    Any kind of help will be appreciated!
    Eileen Manion
    Pearl River, NY

  7. Susan says:

    I saw a black wasp with grass fly up under a wooden shingle. Will the wasp destroy the wood?

  8. Theresa says:

    Wanted to thank you for posting this. I had this issue this week and had no idea what was building the nest. I did see some wasp activity but never heard of grass carrying wasps before.

    • Randall J Thorne says:

      I just cleaned our first floor casement windows, and this is exactly what I found! Found at least 4 nests, some with the larvae still present. We are in Rochester, NY as well.

  9. Corrie DiStefano says:

    Sadly, my grass carrying wasp’s nest was destroyed by another flying insect, something mostly black with a band of white. Definitely not a bald faced hornet, this predator is mostly black, flies similar to a moth. I am kinda upset about this. I really enjoyed watching her build her nest. She seems to be back at though, as is the predator.

    • bugman says:

      Curious. We wonder what that might be.

      • Corrie DiStefano says:

        If I can whack it I will share a photo. It moves quickly and I cannot get a good ID on it. Whatever it is, my patience for it is gone. It is slightly aggressive.

      • Corrie DiStefano says:

        Hi! Turns out it is a tiger bee fly. They typically hunt carpenter bees. This grass carrying wasp built her nest in an empty carpenter bee hole. So, there ya go!!!

  10. Debra A. Mattocks says:

    Is there a bug spray I can use to prevent the grass wasps from building in my window cracks?

  11. Linda says:

    Thank you for this information. I am cleaning all my windows and in every one found these nests. I can’t believe how many there are, up and down the whole track of the screen. And now I also know what a tree cricket is! Truthfully, I feel bad about destroying their nests. Have a nice day.

  12. P Blazek says:

    I am amazed! I had new windows installed in the spring this year, and ever since have been trying to figure out how the grass and bugs keep getting there! I have taken pictures and looked all over the place and finally found the answer here on your website! Now I need to figure out how to keep them from building nests here in the first place! I can finally open my windows but they are now filled with larva, bugs and grass! Thanks for the information!

  13. ROC585 says:

    Wow! Rochester NY here too! July 5th 2020 – 90 degree day.this nest showed up with in 24hrs!
    Just found this nest in my screen door. Looks gross!
    I killed mine with hairspray. Then pulled it out as one hairspray clump. Garbage! ewww.

  14. Terrance says:

    I just found these nest with green katyids in our windows here in Oregon. It’s the first time I’ve run across them–dozens of paralyzed victims. As I cleaned the windows and washed the grooves clean, a wasp appeared and picked up a katyid, then flew away with it.

  15. Donna Sammond says:

    We have these…my cousin read my Facebook post and led me to your site!

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