I know that there is a strong gut reaction to grab for the 'big guns ' when dealing with an over population of a poisonous spider. Sevin is not the chemical to use for a number of reasons.....firstly, as a contact killer, it 'might ' kill those spiders in line for a direct hit but will have zero residual effect. I doubt that Sevin is even recomended for spiders. Sevin will also kill any other critters that may help control these spiders. It's also a dangerous chemical to use around people. There 's no reason to choose that particular chemical.

Having had the pleasure of living through a major BW outbreak myself, I can tell you that the shop vac was our best friend. Put some water with a little dish soap in the canister. Suck the live spiders up, the webs, and the egg sacs. We found hundreds and hundreds of them. Clean up any stacks or piles of stuff around the building and in the garage.

Then, there are several chemicals that are recommended for spiders, most of them in the pyrethrin/pyrethroid family of chemicals. It is those chemicals that the professionals would use though you can find them on your own.

For us, occasional vacuum treatments did the job with that big explosion of the spiders. We kept (and still keep) a broom on the patio just in case...and always inspect the underside of the furniture, the walls, etc. We continue to see occasional BWs in the garage and break out the vac once a year for a good cleaning.

We use Diatomaceous earth in the garage....no chemicals allowed around me.

Good luck. Please don't hesitate to call an exterminator if the
Job seems too intimidating. The last thing you should do is apply something that isn't going to work very well...and is so hazardous, to boot.

You need to know that the spiders had nothing to do with the dead plant.

rhizo 1 -

Thanks for all the helpful info...I really appreciate it. So will the "Diatomaceous earth" be effective in helping to control the BW's? And is this something you buy at your local box store like Lowes or HD?

jean001a -

Thanks for clarifying that the spiders did not kill the plant....I guess it was just awfully coincidental that we found egg sacs at the base of the plant after digging around it.

Michael, DE can be helpful in controlling spiders and other arthropods that tromp through it. I'd sprinkle it in the nooks and crannies as well as other locations where they tend to hide. Yes, horticultural or food grade DE can be found at any garden center. Don't get the DE sold for pool filters.

I thought that I should stress the 'housekeeping ' aspect of your spider control. As you know, these critters can hide out anywhere. You really have to work at eliminating potential locations.

When we clean the garage, we remove everything. Stacks of firewood have been relocated, empty plant containers are now double bagged in plastic. You get the idea.