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Green news from the UC Division of Agriculture and Natural Resources
by Anne E Schellman
on December 7, 2018 at 2:32 PM
Wow! The photo of the spider corpses inside the mud dauber nests is amazing. Thanks for sharing in-depth information about this wasp.
by Phil Geissler
on June 27, 2019 at 8:18 PM
My favorite wasp! I have numerous nests around my house. I will do everything in my power to let them live and thrive on my property! They are a welcome guest!
by Donna
on July 6, 2019 at 4:59 PM
Amazing info! Had I known---I unfortunately just found a "mud cell" (thank u) between my front door & glass screen door. I guess having the proper instinct to scrape it off with a putty knife, but then finding it filled with a variety of small icky spiders (and yes, in barely viable states), I was completely grossed out, but yet amazed like a junior scientist. As I swept this in a small hand-held dust pan, still awed, I was buzzed by a wasp---then seeing another small mud pack above with two evident holes. Slammed the door, called in my big bug killer man, who then sprayed at the upper mast & unfortunately killed what I now discover was a mud dauber. I wish I had known this info and let the wasp go. I will save your info & pass it on to others! Thank you!!
by Nicholas mione
on August 12, 2019 at 10:42 AM
So i smoke and was wondering are mud daubers atracted to or pissed of by tobacco smoke?
by William Baskin
on September 17, 2019 at 8:13 AM
Yes wasps have a paralyzing sting. When I get stung, I have to find a place to lay down because I get great pain from the waist down and unable to walk. It lasts for about 15 minutes and then goes away as fast as it comes on with no side affects. I’ve only been by stung by one mud dauber and usually leave them alone especially since I read this article.
by Emma
on April 25, 2020 at 5:51 AM
OMG THIS IS SO SCARY and also disturbing, take it down. just horrible, just horrible. take it down.
by RC
on June 6, 2020 at 2:55 PM
I just found out about the benefits of Mud Daubers this year. I woefully regret destroying every mud nest I had ever seen. I now leave nests I find on my house alone as I know they will earn their keep getting rid of spiders.
by Judith Dillon
on June 13, 2020 at 12:22 PM
Aside from the dauber "houses" on my home's outside wall and on my door frame in the garage, I'm constantly finding lumpy dauber nests in my YARD, in the grass, with the exit hole open,and firmly attached to the soil. IS there a species of dauber wasp who builds their nests on ground level?
by Chris
on June 24, 2020 at 1:47 PM
I just destroyed a mud dauber home and 5 spiders fell out so I had to immediately Google wtf was going on lol. Some cool looking spiders fell out (googled them too). 2 orb Weaver's with cool line green backs. Forgot what the other 3 were
by CJ
on June 30, 2020 at 12:51 PM
Thanks for the info! And the pic! I cracked open a nest I found on the lawn chair on my back porch and found 10 spiders. One still alive! 3 were black widows I believe! That’s when I looked up your article. So now I’ve put her chair and the beach towel her nest was attached too back where I found it. She’s buzzing around trying to figure out what has happened. I hope she rebuilds so we can enjoy her instead of being scared. We live in a wooded area so spiders are always a problem. We have lots of red wasps here as well so I’ll try not to seat her accidentally. Thanks again!
by Jean Robert Kutzer
on July 2, 2020 at 10:58 AM
I worked as an agricutural consultant for over 20 years. Dr Carlos Bogran formally of Texas A&M and i worked together on many projects. Breaking open several nests of mud daubers in several locations counts were taken and averaged. The results were 70% of spiders in their nests were brow m recluse and black widow. This was only in one rural county anf can bvn be expected to vary a good deal by area but very informative. This wss the brown and yellow variety  
I take the water from ac window units under the window and form a small muddy pool with it to attract them. After being bitten by a black widow these wasps can build me an adobe castle if they are so inclined.
by Melody
on July 29, 2020 at 3:57 PM
I have found a couple of these I knocked down and each one had white spiders in it. I live in Joshua Tree Calif. I also found a white spider on my tomato plant. Can you tell me what kind of spiders these are? My daughter also had a nest at her place in L.A. and it had white spiders too. Are they baby black widows?
by Rachael Freeman Long
on August 2, 2020 at 4:11 PM
White spiders are probably harmless white crab spiders.  
Mud daubers do not build nests in the ground, only above ground. Lumps of soil in a lawn are most likely night crawlers (earth worms).  
I had a friend who's dad would let a faucet drip outside their barn so mud daubers would have plenty of mud to build nests. He knew they were voracious predators of black widow spiders and my friend said they never had problems with spiders.
by Pam
on September 7, 2020 at 11:54 AM
I am so grateful for these informative sites!I now know not to be afraid and I've been watching our mud wasp nest. I have a cool video too!!!
by Cynthia Kirkland
on October 31, 2020 at 6:52 AM
I'd like to submit my photos of my opened mud dauber nest of spiders. Insanely interesting!
by Motlatsi Moletsane
on January 14, 2021 at 2:16 AM
I have just killed one yellow and black mud dauber due to lack of information. I googled it name under "different types of wasps in South Africa" then realized its benefit from this site. I fully regret killing it, as I stay in a place where spiders are a huge nuisance. Thank you so much for the rich information.
by MadeaElla
on May 17, 2021 at 8:19 PM
I took pictures of this mud dauber in the corner of my garage over the frame. It is probably four inches or more thick, and over a foot long. I got worried because the pest guy told me the tiny mud daubers were from when she the person who lived there before me had terminates. Now they did treat for terminates. They had where they drifted the holes then commented them back in. But this dauber has no holes that I can see. And when I moved in, I got up in the middle of the night to grab a water, there were spiders on my walls. Skinny brown ones. Then five black in my shower. I don't kill them. I just put them outside. But I put one out another runs in. So they came and sprayed the next day. But I have not seen anymore spiders in my garage. Just in my kitchen and bathroom. But one or two now. But the walls in the garage are sheet rock, but thru a certain lense they look like they corroding cork board. So something is up.  
Thank you everyone for your notes.
by Bobbi Hatfield
on August 8, 2021 at 1:57 PM
I was just stung by this blue black mud dauber it says they are harmless well let me tell you the sting is worse than a bee sting I was getting out of my vehicle and they must have smelt my body spray and stung me and kept wanting to come back I had to shoo him away
by Heidi
on June 10, 2022 at 11:03 AM
In response to Rachael, mud dauber's actually do and have built nests in the ground. I have several blue mud dauber's here in my gravel,dirt back yard in the summer right now actually, in cental downtown Phoenix Az. They buzz around looking for the holes in the ground where they built their nests. I have small dogs and looked up to see if I should be worried, but after reading this site (thank you!) I will leave them be. My property here in Coronado Historic District is riddled with black widows, which is why the blue dauber is here I suspect
by Rufus
on July 21, 2022 at 9:34 AM
I don't mind them until they start building nests on my house and in my wind chimes. Then they are dead.
by Jeffrey
on July 25, 2022 at 12:42 PM
It's a shame how after reading the article and Educating myself on how beneficial these little guys are... I'm disturbed at how many people still insist on killing them. There are many things in life we don't like but taking the life of something not generally harmful is just wrong. We should be living more at peace with earth and not so hellbent on destroying our beautiful planet.  
I just recently discovered two mud wasp nests on my property. One on my porch an one in my shed. I will not be removing the nests until they go inactive and are abandoned. I did notice last week a wasp crawling around a spider web and was in awe at how they didn't get stuck and actually witnessed it plucking the line. Simply fascinating! This now explains why I haven't noticed the normal amount of spiders.  
I don't know about you but I'd prefer a wasp over a black widow. Do the math... lol  
Thank you for this article. You've changed the way I view these new favorited little guys.
by Rachael F Long
on July 26, 2022 at 3:37 PM
Thank you for your comment! I had a friend who's dad would allow his faucet to drip near his barn so that there'd always be mud for the mud daubbers to build nests with and they never had troubles with blackwidow spiders because they were all preyed upon by the wasps! Great nature based solution to pest control.
by Anne
on July 4, 2023 at 8:35 AM
Just googled looking for how to get rid of wasp mud nests around my doorways and I’m really glad I found this page! Had no idea how effective they are at getting rid of spiders. I never use any pest control and knew that leaving spiders alone is a good way to keep insects under control, but now I will definitely leave the mud nests up so the wasps can in turn prey on the spiders. Thanks, nature. Thanks, internet. And thanks, Cooperative Extensions!
by william wells
on July 31, 2023 at 8:20 AM
Found out the hard way how beneficial the blue black mud wasps are. They are numerous at my country home and terrified my girls. I put out sticky traps and collected hundreds of wasps. Early Fall I started seeing giant black widows with egg sacks on the doors of my garage. This year, i put out a no-kill order on all mud daubers. We'll see if the widow population is high later this year.
by SQ
on August 1, 2023 at 9:22 PM
I love my daubers. Fascinating little creatures. When it's dry in the summer I make mud for them in my yard. They come almost as soon as I turn the hose on. I love hearing them busily build their nests and seeing them flying back and forth carrying their little mud balls. I try and spread the word as much as I can so people will leave their nests alone.
by Gail Nickel
on August 31, 2023 at 7:54 AM
I found 2 daber wasp nests in my attic built in the eves close to numerous hanging spider webs. Will the baby wasps fly out of my attic and go somewhere else to live , or will I have an attic full of wasps?
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