Spider Pests in Your Home

Spiders are an important part of natural balance in nature, getting rid of unwanted insects and being food themselves for birds and other animals. However, most people don’t like spiders in their homes because of the unsightly webs they produce, or because they are startled by the sudden appearance of a scurrying spider. Depending on location, they may also encounter a venomous spider like the black widow, brown recluse, or hobo.

Life Cycle of Spiders
Most indoor spiders’ life cycles are similar. Females deposit as many as 250 eggs into a sac of silk. These sacs are brown, tan, or white in color and are flask-like in shape. Females produce up to 17 of these sacs during a lifetime, resulting in more than 4,000 eggs. Within a week, spiderlings hatch and begin to go through changes within the sac. To nourish themselves, they eat other eggs and spiderlings. The sac dissolves and air currents disperse surviving spiderlings on threads of silk. This process, known as ballooning, allows spiders to populate other areas indoors. Most spiders construct a web to catch insect prey. Many search out corners or high places near where insects may enter or appear.

The poisonous indoor spiders are slightly different. The black widow prefers dark, secluded places to place her web and catch prey, and it is nocturnal. The female also guards her cup-shaped egg sac until the spiderlings hatch. Brown recluse spiders also do not exhibit common house spider behavior. They prefer dark, secluded places, but their webs are not meant to catch prey. The actively hunt. The Hobo, or aggressive house spiders, prefer to spin their funnel-shaped webs near ground level. These webs serve as both traps for prey and shelter for the spiders. When prey vibrates the funnel, the hobo emerges from the narrow end for a meal.

Adult specimens of all spiders may survive for more than a year.

Spider Control and Contact Killers

• Because spiders nest in quiet, undisturbed areas, discourage them by cleaning and vacuuming closets, cellars and other such areas frequently.
• Mechanically remove the webbing. No chemical treatment to dissolve webs is available.
• Eradicate all other insect pests, which are a food source for spiders. As long as food is available, spider infestations will persist.
• Seal buildings with caulk, screening and weather stripping to keep spiders and their food from entering.
• Where possible, wash off outside areas, particularly under roof eaves, with a water hose. Follow with an application of horticultural oil
• Tape or seal boxes, especially in storage areas infested with brown recluse spiders.
• You may wish to transfer spiders outside. Use a glass and a piece of paper. Then they can go after insect pests outdoors.
• Use contact killers. Orange Guard, EcoPCO® ACU, and Victor® Poison-Free Ant Killer are liquids or aerosols. Outdoors, horticultural oil serves as an egg suffocant and web-building deterrent.

See more products for indoor pests in our Cockroaches and Other Indoor Pests section.