2 Major Signs Of Black Widow Spider Infestation

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Black Widow spiders are found in the dark, undisturbed areas such as crawl spaces, basements, and garages. In this guide, you’ll encounter the two major signs of black widow spider infestation. You’ll find out where to look for this manifestation of infestation.

Black widows may also be found near woodpiles, under roofs, or in other sheltered areas. These spiders prefer to live in dark corners, where they hide. In short, in this article, you’ll also learn three easy steps to get rid of them.

What Does the Black Widow Spider Look Like?

Black widow spiders are black with distinctive hourglass-like red marks on their abdomen. They are one of the most easily identifiable spiders, so if you see a spider that matches this description, it is likely a black widow spider.

2 Major Signs Of Black Widow Spider Infestation

Males of the black widow spider species are generally shorter than their female counterparts, and baby black widows are orange and white-colored. Interestingly, the red hourglass on the underside of adult female black widow spiders is often not very visible until they are disturbed.

In addition, the lifespan of a black widow spider is 1-3 years. It takes one year for a black widow spider to shift into an adult from the time it hatches out of the egg.

Types of Black Widow Spiders

The black widow is the most common type, and there are three kinds of black widow spiders in the US:

  • The Northern Black widow
  • The Western black widow
  • The Southern black widow

The southern black widow is common in hot and humid southern states. The key difference between the two is that the western black widow has disconnected red dots or triangles on the abdomen, while the eastern black widow does not.

2 Major Signs Of Black Widow Spider Infestation

Black widow spiders are typically shy and will hide in dark, low-traffic areas when they are not hunting. This can make them difficult to spot. However, there are rare symptoms that you can look out for to help you determine if you have an infestation.

Generally, there are two major signs of a black widow spider infestation:

  • The black widow spider web
  • Egg sac

If you see either of these, there is a high probability that the spiders have taken up residence in your home or workplace.

Black Widow Spider Web-First Sign Of Infestation

When inspecting your property for a black widow spider infestation, the first sign you will likely see is their webs.

The web is the most common sign of an infestation. It is easily recognizable due to its asymmetrical and irregular shape. The web can measure up to 14 inches in both length and breadth, so it is relatively easy to spot.

Female black widow in her nest

Black widow spiders spin three different types of webs: the top layer web, the middle layer web, and the bottom layer web.

The top layer web is the most visible and is made up of strong threads that can be heard when broken. The second layer is a tangled mess with more threads, and this is where you will find the black widow spider.

The third layer of the web is what usually traps crawling bugs, and the spider wraps them in silk before eating them. If you see a web with a lot of trapped bugs, it’s likely that there is an infestation nearby.

Black Widow Spider Egg Sac-Second Sign Of Infestation

If you are seeing black widow spiders around your home, there is a good chance that they have already started to lay eggs. 

The second sign of an infestation is locating black widow spider egg sacs. These egg sacs are spherical in structure, with a tiny notch at the tip. They are often found in sheltered areas, such as under furniture or in dark corners.

Male & Female Black Widow Spider with Egg Sac

Black widow spiders use the same fine silk threads that they use to spin their webs to construct their egg sacs.

The egg sac is around the spongy ball, usually gray or off-white in color and dimensions of about 1/2 inch in diameter. It is often found hanging in clusters from ceilings, rafters, or other protected areas.

After a couple of weeks, the black widow spider eggs will hatch, and the baby black widows will break through the sac. These new spiders will then become adults and start looking for food and mates.

How do we get rid of spiders at home?

Black widow spiders are notorious for being hard to get rid of. They often hide in dark, cluttered, and not-often-visited places inside your home.

There are a few major signs that you have an infestation of black widow spiders in your home. It is significant to take action right away to get rid of the spiders.

There are a few key things you will need to get rid of black widow spiders in your home. You will need a vacuum cleaner, oil-based products like Pyrethrin, essential oils like peppermint essential oil, and spider baits.

First and foremost, remember that black widow spiders can bite you, so be careful when getting rid of them!

black widow spider infestation

Vacuuming the Cluttered Spaces

Vacuuming is an important part of spider control. Not only will it remove black widows and other spiders, but it will also remove their webs. Be sure to vacuum all of the spaces where spiders could be hiding, including corners, closets, under furniture, and storage areas.

The next step is to vacuum the cervices in the house. This will remove any eggs that may be present. After vacuuming, take all of the vacuum cleaner’s contents outside and dispose of them in a trash can.

Black widow spiders like to disguise themselves in cluttered areas, such as cardboard boxes and piles of newspapers. So, if you see an increase in these pests, it’s important to start paying close attention to these types of spaces. Otherwise, you may negotiate with a full-blown black widow spider infestation.

Get Rid Of The Egg Sac

If you find an egg sac, it is best not to touch it. If you try to poke it, you might break the egg sac and attract mother black widow spiders.

When you see an egg sac, you should first pour a generous amount of an oil-based product like Pyrethrin on it. This will kill the eggs or tiny black widow spiders inside. After that, vacuum it up to clean the area.

Spray Essential Oils To Repel Black Widows

Mix peppermint essential oil with water and spray it around the areas where you think they may be nesting. You can also use cedar oil, which is known to be a natural repellent for spiders.

After repelling the spiders, it is important to clean the area. Spiders tend to leave behind webs and eggs, so using white vinegar can help get rid of them.

Keep Spider Baits To Lure Black Widows Out Of Hiding

Black widow spiders can be challenging to get rid of because they can hide almost anywhere. While you’re getting rid of them, it is important to keep spider bait traps near tight places where they can hide. This will help lure them out and make the process easier.

Although you may be successful in getting rid of the spiders with spider bait, it is important to remember that you must also dispose of the spider bait along with the spider. Leaving the bait out will only attract more spiders to your property, and this could lead to a re-infestation.

Black widow spiders usually hide in dark, undisturbed areas. If you have a silicone-based sealant in your home, it can last for at least two decades without reapplying. 

How to Prevent Black Widows 

You can take certain steps to help limit the potential for black widow spider infestations on your property.

  • Remove any web-building spots, such as tall grass or piles of debris, from the landscape.
  • Trim back tall grass and vegetation regularly in your yard; these can be web-building platforms for black widows.
  • If you find a spider in your home, try to capture it and take it outside, so it doesn’t come back in.
  • Ensure that any garden bags or compost heaps are securely fastened to prevent spiders from building webs.
  • Try to avoid using outdoor lighting whenever possible, as it attracts insects and can ultimately increase spiders.

How to treat spider bites

Black widow bites can be quite dangerous. However, it is significant to note that they only bite in self-defense if they feel threatened. 

If a black widow spider’s venom has crunched you, you should first wash the area with soap and water. You can also use a handy ice pack in the area to reduce swelling.

Symptoms of a spider bite may not develop for hours after the bite occurs. Therefore, it is essential to watch out for any symptoms and seek medical attention if necessary.


While black widow spiders are not as common as some of the other types of spiders, they can be harmful. It is necessary to be able to identify the signs of an infestation in order to take steps to get rid of them. In addition to webs and eggs, you may also see the spider itself.

Because of the risk of painful bites and the spiders’ ability to reproduce quickly, you must act as soon as you suspect an infestation.

About the author

A biotechnologist by profession and a passionate pest researcher. I have been one of those people who used to run away from cockroaches and rats due to their pesky features, but then we all get that turn in life when we have to face something.