Brown Recluse Control

Brown Recluse SpiderBrown Recluse SpiderBrown Recluse Spider

Brown recluse spiders are a very common insect pest in West Tennessee and North Mississippi. This area lies directly in the middle of the geographical distribution of these creatures in the country. Brown recluse are different than other spiders, because they actually prefer living in the same environment as we do and will actually move into and reproduce inside a structure versus the more common wolf spiders, who live outside and happen to come inside in their search for food. For identification purposes, the most visible characteristic of brown recluse is the "violin" shaped marking on the part of the body which the legs are attached to. They will range in color from dark brown, light brown to a light tan color. Wolf spiders, often mistaken for brown recluse spiders, have stripes running down their backs.

Brown recluse and wolf spiders are both considered hunting spiders, which means that instead of sitting on a web waiting for prey, they actively search out their food sources. Interestingly enough, it has recently been found that the preferred food source of brown recluse spiders is dead insects. This is easily demonstrated in the field by the observation that if you catch one spider on a glue board, you will catch more than one in an instance of infestation, as the spiders on a glue board serve as bait for the other spiders!

Reducing clutter is necessary for successful control and reduces places for the spiders to hide. Failure to eliminate clutter will cause treatment failure. Brown recluse spiders also live behind walls, in wall voids, and in infested garages, attics, basements, and crawl spaces. The spiders and their distinctive shed skins are often found between joists, sills, and rafters, as well as under insulation. In living areas, they often inhabit crevices behind and beneath beds and furniture, closets, clothing, shoes, and stored items. When sorting through boxes or materials, wear long sleeves and gloves to avoid being bitten. Brown recluse spiders also reside above suspended ceilings, behind baseboards and woodwork, and within heat ducts and registers.

Outdoors, the spiders may be found in barns, sheds, woodpiles, and under anything lying on the ground. Migration indoors can be reduced by moving firewood, building materials, and debris away from foundations. Sealing cracks and holes in a building's exterior can further help to keep spiders and other pests outdoors. Some of the more common entry points for brown recluse spiders include gaps under doors, vents and utility penetrations, beneath the lowermost edge of siding, and where eaves and soffits meet the sides of buildings. Outdoor populations of brown recluse spiders are less common in the northern portions of its range.

Brown Recluse TrapBrown Recluse Control: Control is a three-step process

  1. Glue boards - An important part of a brown recluse control program is the use of glue boards (shown right).  These are placed throughout the structure, at least one per wall in a room, and behind furniture and in accessible areas in the attic where possible. Glue boards are useful not only as a control measure (any spider caught in one is a dead spider) but also as a monitoring tool to determine where hot spots are and as a long term gauge of the success of a control program. We leave these in place to be checked in the course of a control program.

  2. Insecticides-Just spraying and/or fogging a house for a brown recluse infestation will result in failure to control the problem. Be very careful in hiring a pest control company that is going to employ just these methods, because while their service offering may be much cheaper, it will likely be a waste of money. Successful chemical treatments must employ the use of dusts (Delta Dust or Drione) in addition to interior and exterior perimeter sprays to successfully control brown recluse infestations. Since the spiders inhabit wall voids, they must be treated with residual dusts, which can last for years, to kill them. The voids are treated by removing all switch plates and outlet covers and using a dust applicator to push the dust into wall voids that the spiders inhabit. This treatment method is very labor intensive and takes a lot more time than just spraying alone.

    Insecticide sprays are applied along floor/wall junctures, edges of suspended ceilings, and other places where spiders tend to travel. "Bug bombs" and total-release foggers are seldom effective against these spiders, and they should only be considered when treating otherwise inaccessible areas. Treatments will also be made outdoors to help reduce spider entry. Brown Exterminating uses a mist blower to apply a residual chemical 4 feet out on the ground and three feet up on the foundation. This application method is superior because the mist blower machine creates a continuous treated zone, even where there is vegetation outside the house.

  3. Control Expectations- Brown Recluse eradication is not instantaneous. While the initial treatment will significantly reduce numbers, once the house has been treated as described above, it may take a full 6-9 months to be fully effective. When we set the job up, it is necessary to continue with the program for a year after the initial treatment to make sure that it is fully effective. A technician will follow up by reinforcing the perimeter treatments and checking glue boards to monitor activity after the initial treatments. The dust application will not need to be re-done unless necessary, as it is protected from the elements in voids and will last for years.

Avoiding Brown Recluse Spider Bites

Precautions should be taken to lessen the chance of being bitten. Beds should be moved away from walls, drapes and other furnishings, and skirts and bedspreads removed to break contact with the floor. You should thoroughly check your bed before lying down. Shoes and clothing should also be kept off floors, or at least shaken well before wearing. Remove excess clutter and store seldom-used items in plastic storage containers. There may be comfort in knowing that Brown Recluse spiders are not aggressive, and will only bite when they are threatened, usually when humans accidentally contact them in shoes, clothing, or in bed.