# Is my house infested with spiders?



## noquacks (Jun 5, 2010)

People,

The house is in S cal, and every day, 1-3 spiders are seen- sometimes the drop from a web strand anywhere in a particular room. daddy longlegs, and others. I know spiders are difficult to spray for as they are resistant to sprays. I read that "sorptive dusts" are the best- they contain silica gel and pyrethrins that dehydrate their body.

I hope tenting is not necessary......not that Im convinced that would even help......

Any experiences/advice appreciated!


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## Daniel Holzman (Mar 10, 2009)

I assume from your post that you have arachnophobia. There are probably dozens of spiders in my house, and I think that is pretty typical, since spiders like to eat insects, and there are often lots of insects in a house (fruit flies, house flies, mosquitos etc.) I have no problem sharing my house with the spiders, they have never bothered me, so I don't bother them. Perhaps rather than using some harsh chemical in an effort to kill the spiders, which may injure you in the process, you may want to consider removing the food source which is allowing the spiders to thrive. No insects, no spiders. Or you could try to relax about the spiders, there are only a couple of poisonous species in the U.S., and they are far less likely to kill you than a fire, earthquake or other S Cal peril.


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## bubbler (Oct 18, 2010)

Daniel Holzman said:


> you may want to consider removing the food source which is allowing the spiders to thrive. No insects, no spiders.


Last spring I had a similar issue... at least 1-3 spiders every day... I'd come down to breakfast and find two in the kitchen... come home from work... two more... 

I vacuumed all the joists in my basement with a shop vac and I sprayed Ortho Home Defense in all the cracks/openings in the basement. I removed all plants from the house and then started to work on the yard a bit--I had an exterminator spray the perimeter of the house for ants, and I used a general insecticide in the yard via a spreader.

I also turned off my exterior lights at night--light attracts bugs... bugs attract spiders.

I'm pleased to say that this season I haven't seen more than 1-2 spiders total. So either they are gone, or they've learned not to come out in the open... either way I'm OK.

Oh, I'm also running a dehumidifier in the basement to keep it at less than 50% RH.

Being in So Cal you probably don't have a basement? Maybe a crawlspace? I'd consider bug-bombing the crawlspace.


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## noquacks (Jun 5, 2010)

Big thanks, bubler. Im glad you have reduced the spiders. But, what I understand about spiders is you cant really "spray" for them. It is a false economy approach. Sprays are very effective for insects cuz after they walk over the sprayed (dried chemical) they clean themselves and ingest the poison. Spiders are very diferent.

Also, bubler, there is the assumption (our fellow member above makes a lot of assumptions, and judgements) that I have insects as food for the spiders. I done have any insects that I can see anyway. I DID spray for the insects when I moved in. I also "bombed" the house. No effect, period. 

Spiders have this defense mechanism that senses poison mists, for example, and they can just walk away , hide in the walls, and come back out in a week. They can go long periods without food.


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## noquacks (Jun 5, 2010)

Just like you can have an infestation of roaches/fleas etc with little food to support them , you can have a population of spiders without the "assumed" population of insects. I dont mind bugs/spiders/even rats outside my house, but in my house (like your house) it is my domain, and I prefer it with no "pests". Thats why were here at the Pest Forum. 

Gees- these spiders just drop down from nowhere into my salad bowl even. Sheesh. Anyway, still hoping to find a pest guy here with experience with these silica gel products.


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## bubbler (Oct 18, 2010)

Spiders are simple creatures, like all insects--

They aren't going to hatch, grow and live in your home without a food source or reason to stay. So there must be other insects that they are eating and sources of moisture.

They require webs for catching food and places to lay eggs hatch. You *can* break their cycle by cleaning the joists, rafters, removing all webs, vacuum under appliances, inside vents, heater cabinets, under sink cabinets, etc... Seal any/all cracks and crevices you can with expanding foam and caulking (particularly pipe chases, vents, etc).

As for sprays... I agree that residual insecticides may not be effective against spiders, but active mists of spray whether from bomb or you spraying, absolutely do work. My father had a rental home with a crawlspace that was infested with "daddy long legs" spiders and I can tell your first hand that those bug bombs and sprays work. We let off a bomb under that house and there were THOUSANDS of dead spiders under there. Every year for three years he let off those bombs and then one year there were simply no spiders under there.

So, you have to vigilant about doing these things for at least a year or more to break this cycle. I have no spiders this year, but I'm still down in the basement vacuum joists because I DO see webs show up, so there must be some spiders around and I want my house to be an inhospitable environment for them!

Honestly you would not believe believe the number webs and carcasses of "house centipedes" I found in my house the first year, especially the basement... The people who owned the house before me simply did not care, they had water leaks, broken windows, etc... it was bug paradise... I HATE crawling insects and I had a very difficult time handling it, but after a season of cleaning, spraying and sealing, I have no bugs in the house and I intend to keep on top of it.


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## noquacks (Jun 5, 2010)

bubbler said:


> Spiders are simple creatures, like all insects--
> 
> They aren't going to hatch, grow and live in your home without a food source or reason to stay. So there must be other insects that they are eating and sources of moisture.
> 
> ...


Thnaks for the inspiration, bubbler. Good too know your experience. Now, which brand of the "bomb" did you buy? Hone depot? Internet source? 

No basement in my slab house, but plenty of overgrown plants outside. I will star with that. Then, get in attic with something- maybe your bomb. maybe with sorptive dusts, maybe both. why not.

Oh- the house is newly moved into. Sop, very clean- baseboard to baseboard. Thats what puzzles me. Every kitchen cabinet washed/cleaned. I have heard that vacuuming is effective since spiders, although menecaing to insects, are actually MORE delicate , as they do not have the thick armour of insects. A suck up into a vac will kill their delicate bodies.


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## bubbler (Oct 18, 2010)

I have no idea what the brand of bomb was, this was at least 15, maybe 20, years ago. I know that my father has been partial to the "Combat" brand over the years, he's had good luck with their roach and ant gels in his rental buildings.

If you don't own a shop vac, I'd recommend you get one, a nice large one... Once you start using a shop vac for your cleaning, with it's 2" inlet hose and unbelievable suction, you'll never want to go back to a wimpy household vacuum. I use mine with a bag and a HEPA filter. It produces less dust then my old hoover canister, you can probably vacuum for years w/o filling the bag or clogging the filter... although I admit it is a little tough for hauling around the house ;-)

I'd certainly cut back and reduce the plants that are within a foot of house. I'd also check out all the hose bibs, electrical, and around the sill plate to see if there are any cracks you can seal. If you keep your windows open, check your screens to be sure they are as closed as they can be, etc.

If you have central a/c, check that line too--it's a source for moisture because one of the lines gets very cold and will condense water--speaking of, check your furnace and central air handler to be sure that the drain pans are fully draining. You may also want to check your fridge to see if there is any excess water in the pan underneath.

You are correct tho that they can live in places you wouldn't expect them to... I have one of those "Brute" trash cans in my backyard... the lid is always on it because I use it to store my charcoal for the grill... the last half dozen times I opened it I noticed a spider has setup a home in there, complete with a web and everything... I can't figure out why he would want to be there, but he is... unfortunately for him he got crushed by a 25lb bag of charcoal last time I made lunch.


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## noquacks (Jun 5, 2010)

thanks, bub. will do. shop vac is good idea. wet/dry.


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