Prevent Contact With Venomous Spiders

The Black Widow

As you begin to prepare your home and yard for winter, you may be greeted by the appearance of some unwelcome guests. Venomous spiders can be dangerous to outdoor workers, and can occasionally find their way into structures and buildings, presenting a risk indoors as well. Venomous spiders found in the United States include the black widow, the brown recluse and the hobo spider. Most spider bites occur because the spider is unintentionally contacted. You can lessen your chances of being bitten by educating yourself about the identification of these spiders and their habitats and by following some preventive measures.

Venomous spiders are most often found in places where they are unlikely to be disturbed: woodpiles, under eaves, in fences and retaining walls, under piles of rocks and leaves and near foundations. If they venture inside, as they may do when the weather grows colder, the spiders may be found between boxes or other storage items; behind furniture; in closets, basements and attics. Be aware that these spiders usually build their nests between objects; use caution when reaching into an area such as this.

Take the following steps to prevent coming in contact with venomous spiders:

  • Inspect or shake out any clothing, shoes, towels or equipment before use, especially if it was previously piled with other materials on the floor.
  • Wear long sleeves, long pants, gloves and boots when working with stacked or previously undisturbed piles of materials.

    The Brown Recluse

  • Minimize the empty spaces between stacked materials.
  • Remove or reduce debris, including tall grasses and weeds, from around outdoor work areas.
  • Store apparel and equipment in tightly closed bins or bags.

Hobo spiders are not uncommon in our area, are potentially dangerous and should be approached with caution. Hobo spiders are also known as aggressive house spiders because some may bite with little provocation and move forward to attack when cornered or threatened. Hobo spiders are poor climbers, so are rarely found above ground level. They are, however, more commonly found indoors than other venomous spiders. Hobo spiders can be identified by their large size, brown color and distinct yellow markings on their abdomen. Hobo spiders do not have dark bands on their legs like other similar looking spiders.

The hobo spider’s bite has been described as a light prick sensation. Within a few days, however, a severe, slow-healing wound may develop. This wound may scab over and appear harmless, but tissues underneath the scab can begin to die and slough away. If left untreated, this tissue loss may require surgical repair. A severe headache

A Hobo Spider

that does not respond to aspirin is the most common symptom. Other symptoms, including nausea, weakness, fatigue, temporary memory loss and vision impairment may be present, but do not always accompany a bite. It’s important to note that no known deaths have resulted from hobo spider bites; however, a person bitten should seek immediate medical attention.

For more information on venomous spiders, visit the Centers for Disease Control and Prevention.

To learn more about hobo spiders, visit the Montana State University Extension.