Brown Recluse Spiders

by Barbara Lietke on 01/20/2019

Category: Pest Control,
Brown Recluse Spiders

There has been a lot of buzz this past summer surrounding insects in the news, from the Giant Asian Hornets spotted in Arlington Heights to the Cicada Killer Wasps found across the Midwest.  Another perennially terrifying, misunderstood, and pervasive inhabitant of our area is the Brown Recluse Spider. Perhaps no other American spider has fostered so many myths and misrepresentations as the brown recluse.


True to its name, the brown recluse is both brown and reclusive. The body of an adult brown recluse is light brown, except for a darker, violin-shaped marking on the back, immediately behind its eyes. This mark helps identify the spider, though it is not present in young brown recluses. An even more important identifier is the number and arrangement of the eyes. Unlike most spiders which have eight eyes, brown recluse spiders have six eyes arranged in three pairs.


Brown Recluse Spiders are most active at night. During the day they are especially fond of hiding in hidden spaces such as inside cardboard boxes, under table ledges, in crevices in walls and inside of furniture, and in the wood framing of crawlspaces, basements and attics. Rarely are Brown Recluse spiders found in nature outside of structures.


While bites are rare due to their reclusive nature, they do happen. The bite of a brown recluse is usually painless at first; however redness, swelling and a burning sensation develop around the bite within one hour. The red area may enlarge over the next eight hours, and the bite may blister to resemble a bad pimple. Within 24 hours the wound becomes a hardened lump up to 2 inches in diameter, and a scab forms. The wound typically heals within eight weeks.

If skin around the bite becomes purplish, necrosis is likely. If necrosis occurs, it usually does so within four days of the bite. Systemic involvement rarely develops but may include fever, nausea and cramps.


 Most enter the structures by the means of “hitchhiking” into homes in boxes, furniture, and shipping containers, thus, very thorough inspection can go a long way toward keeping them out of your dwelling. A female brown recluse needs to mate only once to produce eggs throughout her life and can produce 150 or more spiderlings in a year. Thus, a single female hitchhiking into a structure is all it takes to establish an infestation. The need to inspect items before moving them in is clear.

Once established in a structure, Brown Recluse infestations are nearly impossible for a homeowner to control without professional pest control services. Though hundreds, or even thousands, of recluse may be hidden inside the structure of a home, they are difficult to spot because of their nocturnal habits and reclusive nature. They are also very fast runners that are difficult to catch or kill.

Determining and treating an infestation:

One way to determine the presence of an infestation is with the aid of sticky traps, which can be purchased from hardware and big-box stores and the internet. These should be placed under and behind furniture, in crawl-spaces and attics, and any other out of the way areas a spider is likely to frequent. This method is helpful not only in determining an infestations presence, but also where the infestation is concentrated.

In addition to the sticky traps, there are other things that need to be done once it has been established that an infestation is present in a structure. Successful brown recluse control requires an integrated management plan that utilizes several control methods. Management plans employing only one means of control, such as spraying baseboards, will fail. This is why it is so important to contact a professional pest-control company such as Midwest Exterminating. Some of the steps that will need to be taken include eliminating clutter, sealing all cracks and crevices in the structure including fireplaces, vents, door and window frames, crawlspace and attic doors, and where cabinets, counters and baseboards meet walls, to permanently prevent brown recluse, and other pests as well, from harboring there.

Pesticides are often a necessary part of brown recluse management. Applications should be targeted on cracks and voids – where brown recluse are known or suspected to be. The use of aerosol foggers is generally ineffective because brown recluse may be hidden so deeply inside items that the “fog” cannot contact them, and those spiders that are contacted may not be killed but driven deeper into hiding. Directed space treatments, where the fog is injected into voids, requiring professionals using specialized equipment, may achieve better results. Additionally, professional formulations of insecticide dust can be used in wall gaps and targeted treatments around the outside of homes may be necessary when spiders are found to be sheltering around a home’s perimeter.

Call Midwest Exterminating today

Because of the potentially serious nature of a Brown Recluse bite and the ineffectiveness of home treatments, the use of a pest control agency is recommended. Give the professionals at Midwest Exterminating a call. We are a family-owned business serving the pest control needs of families in Northern Illinois including Naperville, Lock Port, and the surrounding areas. We guarantee Extermination of all of your Pest Problems with our 6 month Extermination Written Guarantee!

We are open 24 hours a day. Call Midwest Exterminating at 630-968-0200 for a free estimate or to schedule a pest inspection.