Yellow Sac Spiders: The Biting Pest That May Be Lurking Around Your House

Have you noticed any light-colored spider lurking in your home? Yellow sac spiders are quite small and cream or tan colored, and while they are not likely to make a person ill, their bite is one to avoid. Their name comes from the small silk-like sacs or nests, which they tend to place in the upper corners where walls and ceilings meet.

Like other types of spiders, they do bite, and their pinch can be quite painful. Though it lacks venom that is dangerous to most humans, some can suffer from necrosis of the tissue near the bite wound if not cared for properly. However, just like a wasp or a bee sting, some people can have a significant reaction to the bite and should seek medical care. The pain comes from the long, sharp fangs on their head, which tend to stand out as a dark brown color and help make yellow sacs easy to identify. They are not typically interested in humans or pests, preferring to simply go about their day of building a sac and finding food, but they will bite if they feel attacked.

Whether you are dealing with a large infestation or you've seen just a couple and want them out of your home, there are several strategies available to get rid of yellow sac spiders. To do so effectively, you have to deal with the sac or nest created, which can contain nearly 50 eggs, and which the spiders will work to defend.

To know if you're dealing with a yellow sac spider – which is often confused with a brown recluse — there are a few key details to look for. As noted, their pale color is often a good starting point, though they can also have a slightly green color to them as well. Two species commonly found in the U.S. are the cheiracanthium inclusum and cheiracanthium mildei. Of the two, C. mildei is more likely to be in the home. These spiders typically measure under ½ an inch and are easy to overlook due to their coloring.

Most of the time, these spiders will work to seek food, which is typically done at night. They feast on other insects and can be beneficial to some outdoor gardens overrun with other pests. If found outdoors, they are typically located near wood piles or other organic debris. One of the most common ways yellow sac spiders make it into a house is by coming in through agricultural purchases. If you buy grapes, for example, they can lurk in the produce for some time during transport.

Also notable is that when the weather begins to cool down, these warmth-loving arachnids seek shelter by moving indoors, coming in through even the smallest of openings on the exterior of your home. Since they prefer to climb vertical surfaces, any exterior wall crack or crevice is fair game for them to gain access to your home.

As noted, yellow sac spiders can be dangerous to some people, and their bite will hurt both people and pests. Getting rid of a yellow sac spider, then, is ideal. However, just killing what you see isn't enough. The most important way to remove this infestation from your home is to remove the sac itself. Typically light-colored and hard to spot, these sacs are often in the corners of walls. Don't strike them, but use a vacuum to suck them up (and then empty it outside, away from your home). Don't overlook areas like the inside corners of doorways and window jambs. Also note that they can climb into clothing, shoes, and other dark crevices in the home, which makes them easy to miss.

Next, head outside to remove all of the enticing elements that allow these spiders to make their way into your home. Seal all of the cracks and holes on the exterior surface of your home, targeting areas like doorways and windows first. Then, remove all debris from around the home, including wood, piles of leaves, or other structure-like elements that create a home for them. Anything that creates a dark area where they can take shelter is a prime place for them. If you know you have a sensitivity to spider bites, take extra steps to get rid of spiders in your home. This may include seeking out professional pest extermination services.