While spiders can be highly beneficial for your yard or garden, spiders that bite or are poisonous can become problematic. Rather than calling an exterminator, most homeowners can reduce the amount of spiders by modifying behavior and using an appropriate insecticide.
Step 1: Sweep away any webs, egg sacks, and other debris on the outside of your home with a broom or web remover. Pay particular attention to hard to reach areas such as the eaves and near the foundation of your home. Sweep near downspouts and gutters as well.
Step 2: Choose an insecticide appropriate for outdoor use to kill spiders. Most formulas will contain deltamethrin or lamda-chyalothrin. The least expensive formulas will have to be diluted before use.
NOTE: Spiders are not insects, but may formulas used to address spider infestation are called insecticides.
Step 3: Dilute the insecticide if necessary according to the manufacturer’s instructions. Wear rubber gloves and a face shield for protection while mixing the chemicals with water. It is easiest to mix the insecticide in the pump sprayer you intend to use.
Step 4: Remove any pets or children from the area before beginning to treat the exterior of your house from spiders. They must stay inside until the pesticide has dried completely. Also close any windows and doors in your home.
Step 5: Spray any possible entry point to your home including around doors and windows, cable entry points, patios, and dryer vents. Spray around the foundation of the home as well.
Step 6: Set a schedule to spray the exterior of your home that fits with the manufacturer’s instructions until the spider infestation is completely under control for at least two months.
Step 7: Keep the areas inside your home clean and free of spider webs and other debris. Female spiders can lay eggs inside your home, causing a severe infestation once the eggs have hatched and the spiders establish themselves inside.
Step 8: Clean your house regularly to remove clutter that gives spiders a chance to hide. If you see a spider, you can use a can of pesticide safe for indoor use, or catch and release the spider outside.