The Brown Recluse Spider is one of the most dreaded and feared household pests and unfortunately that reputation is deserved due to their caustic bites. Fortunately, the spiders are not blood feeders like bedbugs or mosquitoes. They are predators of other insects and small creatures and only bite people when they are accidently crushed. Brown Recluse are very common in the Midwest. In states like Kansas and Missouri, it is the opinion of many PMP’s that you either have recluse spiders in your house or you will eventually get them. It is only a matter of time.
Brown recluse spiders are in the genus Loxoceles which includes 13 species in the United States. Coloration and markings can vary. All of the species have 6 eyes arranged in pairs and a violin shaped marking on their upper back (called the cephlathorax). The marking has led to the common name “fiddle back” spider.
Recluse spiders are aptly named as they are cryptic and prefer undisturbed areas. They readily infest the insides of furniture, under objects, in corners and in dark areas. Inspections need to be thorough and involve turning over and taking apart furniture where applicable. This author has found brown recluse spiders in drawers of chests, bed frames, recliners, couches and all types of furniture. Keep in mind the predatory nature of the spiders and one will find them where one finds other insects. Hot water heater closets are a great example. When inspecting for these spiders, applicators should look for webbing, egg sacs, cast skins and spiders.
Once an infestation has been identified, the applicator should create, “KILLING ZONES” inside of furniture on the undersides. Treating areas where people will not contact but spiders will hide. Brown recluse do not seem to be repelled by pyrethroid chemistries and many have labels that allow for treatment of furniture. Therefore applicators can put the pyrethroid products where the spiders are hiding and effectively treat them using their “sneaky” against them.
To thoroughly address a brown recluse infestation- the attic, crawlspace, basement and living areas all need to be treated. Brown recluse infestations do not build up overnight and eliminating them overnight is also not likely. PSA: It is very important to help the customer understand that they need to be cautious when putting on shoes, getting in bed or doing anything where they might accidentally crush a brown recluse spider. We don’t want anyone getting bitten.
Once the spider infestation indoors is corrected, the next step is to create a barrier on the outside and maintain that with a regular service program. Without it, brown recluse can re-infest the structure. A perimeter treatment is an effective method to control not only spiders on the exterior but their food source which can also help control these solitary spiders.