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Insect nests between window and frame #593166

Asked August 29, 2019, 8:16 PM EDT

Problem 1: the nest is straw Question: Is this dangerous for the window Problem 2: the nest looks like mud/gravel; loose gravel under window There was some kind of moth in one window, but not sure which window it was on How do I get rid of the insect? We do live in a heavily wooded area so that might be the problem Do they do any damage to windows? I have used a piece of wood and brush to get rid of them and vacuum. Will clean one more time before the snow comes Any help would be appreciated Pat, Good Thunder/Mankato

Blue Earth County Minnesota

Expert Response

Thanks for the question.

I don't have an immediate answer but do have a few questions.

1).  How long ago did you notice them?

2).  When you cleaned out these nests, how quickly were they rebuilt?

3).  Any mice and/or squirrel problems at your house?
 
Looking forward to your getting back to me.

Many thanks!!



An Ask Extension Expert Replied August 29, 2019, 8:36 PM EDT

Thanks for question.

In consultation with another Master Gardener, we have decided that these nests are insect nests.  They could have been constructed by either a mud dauber or a grass carrying wasp.  We would suggest that you just remove this nest material.  This should eliminate the issue for the time being though you may see some recurrence of them next year.

For more information about mud daubers, see:

https://hortnews.extension.iastate.edu/mud-dauber-wasp

https://www.alamy.com/stock-photo/wasp-mud-dauber-nest.html

More about grass carrying wasp, see:

https://www.canr.msu.edu/news/the_grass_carrying_wasp_a_solitary_wasp_that_builds_nests_in_unusual_places

http://bugoftheweek.com/blog/2017/10/24/window-wasps-grass-carrying-wasps-iisodontiai-spp

Good Luck!!

An Ask Extension Expert Replied August 29, 2019, 11:32 PM EDT
Thank you so very much with all the information and your quickness. Appreciated!!!Thank you!!
The Question Asker Replied August 30, 2019, 10:04 AM EDT
You are entirely welcome.  Glad to be of help.

Thanks for using our forum
An Ask Extension Expert Replied August 30, 2019, 10:06 AM EDT
 Whenever I open windows and grass/straw come flying in, I know the insects have been acdtive.
I clean them out 2 times/summere-fall. Just cleaned them out now in August.  Not sure if they will rebuild again, but I will keep track of when they make their nests.

We have no mice problem but we have squirrels.

Thank you
The Question Asker Replied August 30, 2019, 10:08 AM EDT
 

If the mud structures are due to the mud dauber, inside these structures will be larvae of the insect.  These larvae are completely harmless.  If you do not remove these structures, the larvae may over winter in them in cocoon form and emerge as adults next spring.  By eliminating these structures now, there should be no adult wasps next year.  See:

https://animalcorner.co.uk/animals/mud-dauber-wasp/

If the grass nests are due to the grass carrying wasp, the situation is very much the same as with mud daubers.  Inside the grass nests are larvae that will overwinter as cocoons.  These larvae are also quite harmless.  Removing these nests within the next couple weeks will greatly minimize the possibility of seeing adults next spring.  See:

https://ento.psu.edu/extension/factsheets/grass-carrying-wasp

For what’s it worth, both of these insects are important pollinators.

Thanks again for bringing your observations to our attention!

An Ask Extension Expert Replied August 30, 2019, 10:38 AM EDT

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