We have a sign posted in our field offices which says "No mata las aranas!"--Don't kill the spiders!. This is to remind everyone that, despite their bad reputation, spiders are very helpful in controlling insect populations in the landscape. Garden spiders are general predators, feeding upon whatever insects happen into their path or web. Some spiders will bite humans (black widows and violin spiders are known to be dangerous, although other species can inflict painful bites requiring medical attention) but only in self-defense. So, we don't go out of our way to kill or bother spiders in the landscape.
However, if spiders are causing a problem at your site, we can control them with chemical treatments. The most common problem with spiders is the unsightly appearance of their webs on building walls and shrubbery. Webs are best controlled by regular cleaning by spraying water, raking or blowing. This discourages the spiders from using the area for a home or feeding grounds.