What's That Bug? does not endorse extermination

Subject: Mysterious Cellar Spiders Covered in White
Location: Castine, Maine
September 4, 2012 3:55 pm
bugman,
I have read a few of the comments concerning the mysterious spiders apparently covered with a white frosty-looking substance. I have seen these in Maine, and am cleaning a few pictures of them off of my desktop. The ones I saw were definitely dead, as I could touch them with a stick with no reaction.
Signature: Andrew

Fungus-Ridden Spider

Hi Andrew,
Thank you for your first-hand observations and photographs of this Fungus-Ridden Spider phenomenon.  One of our most frequently commented upon postings has sparked a debate on whether these spiders are dead or alive.  We maintain it is a fungus infection and it is possible that some of the spiders might not have completely expired, but they are not long for this world.  We believe the fungus might attack the spiders while alive, but death shortly follows.

Fungus-Ridden Spiders in the basement!!!

What's That Bug? does not endorse extermination
Location: Castine, Maine
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33 Responses to Fungus-Ridden Spiders in Cellar

  1. kaisparents says:

    I was trying to figure out what the creepy white spiders in our basement are. Then I happened upon this site. These are the exact, ALIVE, spiders we have in the basement of our 1930’s new England home. I assure you they are very much alive! Are they dangerous?

  2. JessiR says:

    I have this exact same thing in my basement. There are literally hundreds of them. fyi I live in north central Wisconsin.

  3. Crystal says:

    I just read of a fungus that is a natural pesticide called beauveria bassiana. It apparently kills bugs, then grows on the carcass & waits for it’s next bug victim. Perhaps that is what is going on with these spiders?

  4. rebecca says:

    I have thousands of these under my house. the house is on a brick laid foundation by the river in central Wisconsin. I do live in this house with my husband and 3 small children we do end up with a LOT of wolf spiders in the home. Is there any concerns that I should be aware of.

    • bugman says:

      While we expect there are many concerns, the Wolf Spiders and Fungus Ridden Spiders should not cause you any problems.

  5. Lynn Erickson says:

    I was saddened yesterday to find dozens of dead, fungus-ridden cellar spiders hanging upside-down in the basement of a home we are considering purchasing. The space is continuously damp, prime breeding ground for fungus; but these are big cellar spiders, and lots of them, so there must have been a healthy population at some point. So when and how did this fungal infection begin? More to the point, I LIKE spiders, and don’t want something in my house that will destroy them. So – how do I get rid of the fungus?!

    • bugman says:

      We suspect that these fungus infections are intermittent outbreaks and that not all spiders succumb. You can start by cleaning up the corpses which should help to eliminate infections in future generations. We hope some mycologist will be able to provide you with more specific information.
      Many other insects are also prone to fungus infections.  BugGuide has developed a page profiling these infestations.

  6. kara says:

    Funny how I come across this! I once saw Huge fungus spiders in an old abandoned home awhile back. I blew on them and they moved. I was really creeped out and they were very big. It was in New York by the way. I’m glad to finally know what it was I saw!

  7. Courtney says:

    We live in PA an we just found tons of these in my mothers basement all dead though. they worried me i have a 5 yr old an he is with my parents alot. i’m glade to now know what it is..

  8. Dave Splieth says:

    Just one week ago I was in Canton, PA Oct.12, 2013 to help a family member with winterizing his mobile home.
    Underneath in the crawl space were dozens of these spooky looking fuzzy white encased spiders and webs. Some of them were moving but very slowly. We spoke with other owners and they have same issue. We would like to see some information on this phenomenon.

  9. Tana says:

    10/3/2014 thank goodness for this! I have been loosing sleep over what the hell was going on in our basement!

  10. anne says:

    Could this be due to mold? I sell real estate in southwest wi and stumbled upon these last night. This particular home had a serious mold problem and the basement was very damp.

  11. Michelle Bustamante says:

    We saw these spiders in the basement…….the exact spiders in this article….thank to everyone for commenting……I will go downstairs with a broom and wipe all cobwebs down…..it is very damp downstairs and dark…….was creeped out….thank you for all the comments…..we live in Meriden, NH….this is a very old farm house, beautiful everywhere else as it was all remodeled WILL NOT BE SPENDING A LOT OF TIME DOWNSTAIRS…..LOL. Question, I am a severe asthmatic should I be concerned???

    • bugman says:

      We are sorry, but we are unable to make any medical diagnoses. You should check with your physician regarding any links between fungus infected spiders and asthma.

  12. ann says:

    Relaxed at last! No one knew what they were, thanks Bug Man!!! Plymouth Borough, Pa.

  13. Krysten says:

    My neighbor has a ton of these and been searching for a long time. Many accused us of these being fake. Now I know I’m not crazy. We are in Northwest ohio.

  14. john b says:

    I would like know if anyone one got sick from crawling in craw space with fungo spiders , have to install pipe do not really want to get ill.

  15. Sue says:

    I found tons of these in my basement would love any more info.

  16. The fungus must be Torrubiella pulvinata that only infects cellar spiders.

  17. Bucatini says:

    Was just searching for information as I rent a council garage for my car and have seen a few of these. All dead in my case but looked like someone had sprayed them in foam. Not a spider fan so I just remove them with a broom.

    SR
    Southampton, England

  18. Thea Hall says:

    We have 100s of these under my house, but the web appears to be crystallized too. Looks like they have been sprayed with hydrogen. Is this harmful to human?? My husband and I have been since for a couple of months. I have asthma, and the spider are directly under my bedroom.

  19. Dane Coyle says:

    I saw these for the first time yesterday in a craw space. I am wondering if it could be from the spiders drinking salt water. I still have to go back to the home and check if the water softener is draining into the craw space, due to it being very wet under the house. Any comments would be appreciated.

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