Spiders are one of the most amazing and feared home invaders. There are more phobias about spiders than any other pest and understandably so. If you get bitten by the wrong spider and you have a bad reaction to the venom, you can end up in the hospital. And yes, there have been some deaths associated with spiders (though much less than you would think- six per decade in the US)
They can be found indoors any time during the year but their numbers usually peak during late summer and fall, just in time for Halloween.
Because of their beneficial nature and how very important they are to the environment, we should tolerate spiders whenever possible. When tolerance is not possible don’t expect perfection in spider control; they are biologically not very receptive to chemical agents and not very cooperative in picking up pesticides. So just spraying alone is not a great defense.
One good point about spiders is that they are basically loners. They aren’t social insects that live in big groups. As predators, they like to operate on their own and not share his food. So you are often just as effective whacking a spider with a shoe, a newspaper or whatever weapon of choice as you would be to spray for them.
To reduce the number of spiders in and around your home, start with non-chemical methods to prevent spiders from entering from the outside.
1- Remove debris such as bricks or firewood away from your home.
2- Keep grassy areas near building cut short.
3- Trim back shrubs and other plants that directly contact your home.
4- Knock webs and any egg sacs down with a broom or a hard spray of water.
5- Caulk or seal obvious cracks around the foundation, doors and windows.
6- Repair any screens that fit poorly or are damaged.
7- Change outside lights to reduce insect prey that can encourage spiders. Yellow lights are less attractive to insects than mercury or sodium vapor lights.
Regular housecleaning is very important in the control of spiders indoors. Large persistent spider population indoors indicates the presence of a significant insect population that serves as their food.
To supplement your sanitation efforts an insecticide treatment can be performed, concentrating especially in, cracks, crevices, voids and other places where spiders may hide. Fogging or bombing is not effective.