Invasion!

September 19, 2012 8:58 PM

Help! We just found a black widow spider inside our house. They are endemic in our neighborhood. What do we do?

I'm guessing there are probably more if we found one. Do we sleep elsewhere? Do we get a fumigator tomorrow? I'm concerned for our safety and that of our dog.

posted by anonnymoose to Home & Garden (19 answers total)

Where do you live? Here in Arizona, black widows are common but easy to avoid. Their webs are messy-looking, low to the ground, and noticeably tougher than a regular spider web. They don't go wandering around a lot, they generally stick close to their web. They hide in crevices near their web during the day, but come out at night. They aren't aggressive at all, you practically have to poke one with your finger to get it to bite you.
posted by TungstenChef at 9:03 PM on September 19, 2012 [2 favorites]

Response by poster: I'm in Arizona too. We are very careful, but this is an old property with crannies. The offender is hanging out under the dishwasher.
posted by anonnymoose at 9:04 PM on September 19, 2012

Best answer: Here's what the university of Arizona has to say on the matter:

MANAGEMENT:

Prevention

• Be cautious when picking up or moving objects, particularly in outbuildings such as shed or garages, or in shady undisturbed areas such as under parked cars or in flower pots.
• Although they are not commonly found indoors it is always a good idea to shake out and check clothing before putting it on (for brown spiders and scorpions as well).
• Manage household, yard and garden insect pests (roaches, crickets etc.). Lack of food will discourage spiders and force them to move elsewhere.
• Keep out door lighting off as much as possible to prevent luring insects which the spiders feed upon.
• Remove collections of paper, boxes, rubbish piles in the house, attic, storage areas, etc.

Management

• Destroy webs, egg sacs, and spiders by brushing or vacuuming.
• Use a fly swatter to crush.
• Only if necessary, spray spiders at night, when they are active, with a pesticide labeled for use on spiders. Follow the directions on the label explicitly.

(Frankly, I'd just live like normal, but then I live with an arachnologist and she's convinced me that spiders ain't no thang to worry about)
posted by barnacles at 9:14 PM on September 19, 2012 [5 favorites]

Ours turned out to be a false widow rather than, as we originally thought, a black widow. But what I learned is that it seemed more dangerous to try to remove her than let her be.

They are not active during the day, they don't wander, they hide in the corner of their web and come out just to wrap up and eat prey. They only bite when messed with. Even if you do get bitten, it's only truly dangerous for children/elderly/immune-compromised.

If she's under the dishwasher, is it even a place that the dog can get to?
posted by desuetude at 9:16 PM on September 19, 2012

Response by poster: It's actually in front of the dishwasher by the floor, and yep, we have a very inquisitive pup who has a diggy snout and just looooves to chase and eat bugs of all kinds.

Thanks for the info so far, especially the stuff from UA.
posted by anonnymoose at 9:22 PM on September 19, 2012

As desuetude says, the widow is going to stay put under your dishwasher. You can leave it there tonight, it'll just sit in the web waiting for bugs. I don't like having them lurking around, any bug spray (pesticide, not repellant) you get at the hardware store should kill them if you spray them directly. You can look for them by walking around after dark with a flashlight, their main pray is nocturnal beetles so they sit in their webs at night with their abdomens generally facing up.
posted by TungstenChef at 9:24 PM on September 19, 2012

Demon WP. Although you have a dog, so keep that in mind.
posted by phaedon at 9:50 PM on September 19, 2012

When we lived in a warmer area we were plagued with black widows--especially warm, moist areas. I would turn out the lights at night and with a flashlight find the webs--they are very very shiny with a flashlight--and see the black widow on the web. THEN SQUISH!! Really and truly, just squish! Then when you're sure it's dead destroy the web. The next night lights off again and look with flashlight--if there's another BW it will build pretty much by the dead one's web. Keep checking nightly, and go around other exposed areas with the flashlight. Don't feel bad about squishing, they are invading YOUR space! Be diligent, it won't probably take too long every night, and you will keep seeing them around the same areas. I have never shot a deer, elk, etc., but the satisfaction I get when squishing a BW is primal! :)
posted by msleann at 10:01 PM on September 19, 2012 [3 favorites]

[Removed some comments. Its ok to offer alternative solutions but please refrain from chiding other posters.]
posted by vacapinta at 3:01 AM on September 20, 2012

One summer here in SoCal they just seemed to be everywhere. I was terrified, because I had a curious toddler and a nosy dog who loved to dig. But even after finding close to 20 of them in and around the house (including one under a lounge pillow I was resting on, gah), I have to agree with TungstenChef above- they really aren't aggressive. If you're concerned for your dog, contact your vet and find out what precautions you can take that are dog specific and what first aid you should have on hand in the event your pooch does sustain a bite. Better to have some meds on hand and the knowledge of what to look for & how to treat it than to be torturing yourself over what lurking under the appliances.
And then I'd pull out the longest vacuum attachment I could find and slurp that sucker up. It might not solve the larger problem, but it's good for your morale.
posted by biddeford at 3:22 AM on September 20, 2012 [1 favorite]

Best answer: I'm spider-friendly, but Black Widows are dangerous to pets (see Spiderzrule.com's Spider Bites and Your Pet) and possibly fatal for cats and small dogs (cite, though it doesn't seem to be loading at the moment).

Personally, I would not go with fumigation as the first step. I would kill or remove the spider you have found, then follow the Black Widow Management Guidelines from UC Davis to clear the house and perimeter.

Note that they say, "Typically pesticide control of spiders is difficult. Various insecticides are registered for control of spiders including pyrethrins, resmethrin, allethrin, or combinations of these products; however, they usually aren’t very effective. Sprays work only if you apply them directly to the spider or their web, since the spray residual does not have a long-lasting effect. This means a spider can walk over a sprayed surface a few days—and in many cases, a few hours—after treatment and not be affected. Sprays won’t affect egg sacs, and if you apply them to the outside perimeter of a structure, they won’t keep spiders from moving in."

Given this, and the fact that I'd prefer not to have toxic insecticides around my family or dog, I'd go to town with clearing clutter inside and out, sealing whatever I could, and wielding the vacuum / dustbuster in every nook and cranny. Then, in the how-can-it-hurt department, I'd probably try an essential oil / water / dish detergent spray that may deter or repel spiders to some degree. There are a lot of do-it-yourself versions on the web, such as Spider Deterrents (scroll to bottom), but the simplest seems to be several drops of lemon essential oil and liquid dish detergent added to a quart of water in a spray bottle: spray surfaces and areas where spiders might be attracted to set up house. I'd do this regularly, because hey – lemony, clean, non-poison, and maybe it helps. Some people recommend eucalyptus, but I'd only use that in areas my dog couldn't get to.*
posted by taz at 4:23 AM on September 20, 2012 [2 favorites]

The offender is hanging out under the dishwasher.

So vacuum it up with a wand attachment?
posted by DarlingBri at 4:35 AM on September 20, 2012 [1 favorite]

The best way to get rid of spiders is to remove their food source. If you keep a reasonably clean house and sprinkle one of those insect killers around the foundation of your house to prevent insects from coming in, there won't be anything for the spiders to eat and they will have no reason to be there.
posted by sanka at 5:46 AM on September 20, 2012

This long-time black widow suffer says: please remove the offending spider from your home as soon as possible! :) What you are avoiding is a hiden egg sack, exactly what she's getting ready to build any day now. Remove her any way you please, I prefer the live method via lidded jar, but widows are pretty fragile. They do move fast though. If you have one egg sack hatch, it will take years to rid yourself of them. Do yourself a favor. Trust me, the species will survive!
posted by PixieS at 6:24 AM on September 20, 2012

I know a couple people who have been bitten my black widows and it was not a walk in the park, by any means. I've also been charged by a few in broad daylight, so I'm always skeptical of how retiring they're made out to be.

Vacuuming everything in the house is good, as well as clearing any brush from around the perimeter of the house. When I was growing up, my dad used to go out every other night or so with a flashlight and stick to look for spiders, kill them, and destroy the webs.

We also found that once we stopped letting our cats out, the lizard population in the yard rose, and the black widow population fell. Here's an article on attracting lizards to your yard.
posted by Squeak Attack at 7:16 AM on September 20, 2012 [2 favorites]

Response by poster: Thanks again. I think this makes the plan of "attack" much clearer. Spraying chemicals inside the house gives me the heebie-jeebies, so it's good to get alternative suggestions.
posted by anonnymoose at 8:20 AM on September 20, 2012 [1 favorite]

We get black widows around and, in, our house from time to time. Earlier this summer a big one setup camp in the minivan. (not cool!)

My favorite removal method is the shop-vac but I've used the house vacuum too. Wait 'till it's dark, gently get the nozzle close to the spider then hit the switch.
posted by shino-boy at 11:16 AM on September 20, 2012 [1 favorite]

We have black widows. I haven't yet found any inside the house. Sometimes one will make a nest on the front porch, near where we sit. I kill them there. They live elsewhere in our yard, but in peace.

Children seem more vulnerable because they don't think about sticking their little hands in places where she is likely to build her web. I've never been attacked by a black widow. When I was a child, my uncle was once bitten by one that was hiding under the seat in the outhouse. He was not pleased, but he didn't die. I guess he wasn't thinking about what dangles, but I've always been leery about outhouses ever since. My experience with black widows is that in the daytime they tend to run for cover when they sense movement near their web, but will come out to investigate if you touch it.

You might do well to check into the habits and habitats of the Recluse types of spiders. I saw quite a few of them when I lived in southern Arizona as a child. They can be aggressive, and their bite is pretty dangerous.
posted by mule98J at 11:44 AM on September 20, 2012

Get a long stick, something like a yardstick would be good. Wave it around under the dishwasher. Have a torch ready, preferably the kind that lights automatically -- if it goes wrong with the spider, they are too easy to knock over. Burn any spiders and egg sacs you've captured (pick a good place to do this in advance). Have something ready to quickly put out burning bits of stick, like a bucket of water.

An alternative method is to find someone who thinks their bites aren't all that bad (Only life threatening in certain cases!) and get them to stick their hand under there and save the spider from your evil plan. Provide them with a jar so they can take the spider to their house.

Been bitten by one. Didn't see it beforehand. They don't know you're pestering them accidentally.
posted by yohko at 10:24 PM on September 20, 2012