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How Dangerous Are The Yellow Sac Spiders In New England?

a yellow sac spider crawling inside of a flower

The yellow sac spider, also known as the black-footed spider, is a nuisance pest that is undoubtedly upsetting to spot in your home or business. These creepy crawlers are a light, pale yellow with a greenish tint and measure between 0.25 and 0.38 inches long. Their abdomens are pale yellow/light gray and sometimes have an orange-brown stripe running down the middle. Their cephalothorax, which is the head and thorax fused together, is an orangey-brownish-red color and they have eight dark eyes in two horizontal rows on either side of their head. Their front legs are longer than their back legs and they have a leg span of up to one inch.

 Yellow sac spiders have a pair of chelicerae, which are claw-like appendages in front of their mouth. Their fangs easily penetrate human skin and although a yellow sac spider bite isn’t fatal, it can be quite dangerous. People often confuse yellow sac spider bites with brown recluse spider bites, but the latter are much more dangerous.

 When a yellow sac spider bites you, they inject a venom that has a toxic effect on cells and can be poisonous to nerve tissue. The bite usually causes pain and discomfort lasting up to two hours. Many people experience redness, swelling, and burning, and may even experience headaches, nausea, and vomiting.

 These pests usually bite humans during outdoor activities like gardening or mowing the lawn. They get caught in the folds of your clothing and cause damaging necrotic bites that can kill skin tissue.

 Yellow sac spiders usually make their way inside during the summer months as they seek a place to cool off and find food. They gain entry through small structural cracks and are usually found crawling up walls and other vertical surfaces. They can also get inside through rotting wood that has been weakened from water damage. 

 As their name suggests, they create silken sacs in protected areas underneath logs or timber, leaves, plants, debris on the ground, and rocks. They do not weave webs but are often found where the walls meet the ceiling. As nighttime hunters, they emerge from their sacs at twilight to find prey. 

 There are a number of preventative measures you can take to reduce your chances of a yellow sac spider infestation:

  1. Upon spotting their silken sacs, get rid of them immediately. You can use a vacuum to remove them from ceiling corners. Once removed, discard the vacuum bag to prevent them from spreading further.
  2. Seal up any holes, cracks, or gaps in the foundation, doors, and windows, as they can easily gain entry through these tiny openings.
  3. Eliminate moisture and sources of food, like little bugs and other insects.
  4. Remove inside clutter and storage items. This eliminates possible harborage areas where yellow sac spiders can hide in their silken sacs until feeding time.
  5. Remove yard debris like logs, rocks, leaves, woodpiles, and dead vegetation.

The thing to remember about yellow sac spiders is that they’re very good at hiding. Not only that, but because they only emerge for feeding at night while we are asleep, an infestation can go unnoticed for long periods of time. The best thing you can do to protect your home from these sneaky pests is to contact the professionals at Big Blue Bug Solutions.

 Our team of licensed and certified experts is experienced at identifying, eliminating, and preventing yellow sac spider infestations so you don’t have to. We offer a variety of residential and commercial services that are customized to fit your individual needs. From indoor inspection to outdoor perimeter treatments, we’ve got you covered. Our homeowner’s plan provides year-round pest control and includes three preventative maintenance visits throughout the year. In the event that a pest returns between visits, we provide re-treatment at no additional cost. Call us today for a consultation and rid your property of pests once and for all.