It is not uncommon for residents of Massachusetts to find spiders in their home, sometimes in large numbers, but luckily, the northern black widow is the only potentially dangerous spider species in the state, and they are very rarely spotted outdoors, let alone within homes. One spider species that has been associated with medically significant bites is the yellow sac spider, and unfortunately, these spiders are frequently found within Massachusetts homes. Yellow sac spiders are often spotted skittering across walls, and they are recognizable for their light green color and long legs. According to a recent nationwide survey of pest control professionals, the yellow sac spider was the sixth most commonly managed spider species within homes during 2016. These spiders are likely responsible for the majority of spider bites sustained within homes, as they are unusually aggressive, and are known for biting humans without provocation. However, serious medical conditions very rarely result from their bites.

While wolf spiders are intimidating to look at, and are often mistaken for tarantulas, these frequent home invaders are shy around humans and their bites are harmless. The spiders most likely to be found in large numbers within homes are cellar spiders, American house spiders, and although they are not true spiders, harvestman, which are more commonly known as “daddy long legs.” Although spiders reduce the number of insect pests within homes, most people cannot tolerate their presence, and this makes spiders one of the most commonly controlled arthropods within homes. The best method of spider control is exclusion, which involves the elimination of all potential entry points into a home. Examples include installing door sweeps, foundation screens, and using caulk to seal cracks, crevices and other potential entry points on the exterior walls of structures. Applying insecticide to potential entry points, such as long the bottom of door frames, crawl space openings, window sills and entry points on exterior walls will provide a temporary barrier, but few insecticides that are available to consumers offer residual spider control.

Have you ever had success with an over-the-counter spider control formulation?