Sometimes it seems as if spiders have invaded our homes and gardens. No matter where you look, spiders and their webs lurk behind furniture, over windows, in corners of rooms, in light fixtures, on ceilings and under cabinets. Outside, they occupy flower pots and build webs between foliage and live under eaves.

Most spiders, even if they are scary to look at, are harmless to humans. Spiders usually avoid places frequented by people. They prefer to live in places that are undisturbed, catching and feeding on unwanted insects such as moths, mosquitoes, flies and beetles. Spiders are particularly beneficial in the garden because they feed on garden pests that affect the health of plants.

There are steps you can take yourself to reduce the occurrence of indoor spiders. Vacuuming regularly removes spiders and their webs. Clean behind furniture, in corners and in and around windows. Use screens to prevent other insects from entering the building. Because spiders feed on other insects, an abundance of spiders may indicate a problem with other unwanted insects as well.

While most spiders are innocuous to humans, a few species have a poisonous bite. The bites of black widow and brown recluse spiders can cause reactions in humans ranging from pain in the area of the bite to muscle cramping, fever, vomiting or difficulty breathing. Both the black widow, identifiable by a red splotch on the abdomen, and brown recluse, identifiable by a brown violin shape on its head, are common in the southeastern and western United States, but are found throughout North America. If you have a problem with spiders, the professional exterminators at Bircher Exterminating can recommend appropriate treatment for spider control.