Preventing bites by hobo spiders in high risk situations calls for simple, common sense measures. When working in enclosed infested areas, particularly in such places as the crawl spaces beneath mobile homes, wear protective clothing, including long sleeves tucked into gloves, long pants tucked into boots, and coveralls or a jacket with a hood. Rubber bands over pant legs and sleeves will minimize the possibility of a spider running up an arm or leg in a confined situation. Wear gloves when working outdoors in potential habitats such as rock gardens, and when moving wood. Keep bare hands out of places that you cannot see, and do not use bare hands to turn over possible hiding places: Many bites by snakes and spiders occur when the victim uses bare fingers to turn over wood or other objects that conceal the hidden organism.
Indoors, shake clothing out that has been stored or laid down in spider inhabited dwellings. Exercise caution when moving boxes or other objects that have been stored in basements, cellars or greenhouses within the range of the hobo spider. A significant number of hobo spider bites occur in bed, when the sleeping person inadvertently rolls over or places a limb on the arachnid. In many instances this could be prevented by eliminating the spiders' means of getting in or onto the bed. Hobo spiders usually get onto beds by climbing bedspreads or other linen which touches, or is very close to the floor; they are not proficient at scaling slick surfaces, such as polished wood or metal bedposts. Keeping the sides and the front of bedspreads at least eight inches above the floor, and keeping beds at least eight inches from walls with porous surfaces, will minimize the possibility of acquiring an unwelcome eight-legged bed partner.
Measures aimed at controlling hobo spider populations should start by eliminating suitable habitat around infested areas. In the late summer and early fall these spiders (particularly females) and their webs can be found beneath rocks, wood, lawn ornaments and debris; hobo spiders inhabit the undersides of objects such as this, and require a small amount of space between the soil and the bottom of the object chosen as a web site. When placing decorative objects in gardens or lawns, firmly anchoring the base of these items into the soil (leaving no space between the soil and the objects' base) will prevent spiders from nesting there. The undersides of decorative railroad ties are a favorite micro-habitat of hobo spiders; anchor the base of ties firmly into the ground, and use caulking or other sealant to close off cracks between stacked ties.
The hobo is a spider which often enters living quarters when searching for mates, etc. Keeping hobo spiders out of houses in heavily infested areas is a challenge. In such areas one should inspect the foundation of dwellings and seal off potential entry-ways such as deep cracks in concrete, spaces beneath doors, loose fitting panels in window wells, etc. Screening off dryer vents from the outside is also recommended. Dealing with hobo spiders inside of dwellings should include routine household cleaning, making certain to thoroughly vacuum in corners and closets, behind furniture, and underneath beds.
Spider Traps - Eagle Rock Research is not recommending specific brands of Glue Traps at this time. Previous experience has shown that traps baited with attractant are most effective. This attractant appears as a blue dash in the sticky center of the trap surface and may not work well if the traps are old or have been stored in hot conditions. Several companies have illegally used photos from this website on their products. If you find traps with pictures or text from this website please advise us using the email link on the main page.
Chemical control of hobo spiders, indoors or out, should be considered only in situations where large infestations are present and other measures have failed. Due to the mobile nature of this species, it is virtually impossible to completely eradicate hobo spider populations. While pesticide use to control the hobo may sound very easy and appealing, very rarely does it yield long term results, regardless of the technique or the chemical agent(s) used. Pesticide use during the active season for adults (late July through October) is the least effective: The application of pesticides outside (along foundations and beneath low shrubbery) in late June (when the spiders are not abundant on the surface) will kill both recently hatched juveniles and soon to emerge adults. The single most effective deterrent against the hobo spider is the presence of competing spider species; if such competing species are eliminated by indiscriminate spraying, the reinfestation of the hobo spider is virtually guaranteed.
When using pesticides on your own, always read and follow labeled directions, and make sure that the product is rated for the specific type of area (indoors or out) that you intend to spray, etc.: apply such materials only in low areas where hobo spiders are likely to be found. For indoor applications chlorpyrifos (Dursban), propoxur (Baygon), bendiocarb, and diazinon have been suggested by various authors for potential use against hobo spiders. The use of aerosol bombs or foggers can help reduce populations in crawl spaces or other enclosed areas, but it is usually necessary to fog both such spaces and any adjoining units. In several instances where aerosol bombs have been applied in basements or crawl spaces alone, the hobo has simply moved upstairs, directly into the living quarters. For outdoor applications chlorpyrifos, diazinon, or malathion can be applied around foundations, window wells, outbuildings, etc. Once again, the application of pesticides much above ground level is not recommended in attempting to control hobo spiders. In circumstances where severe infestations pose a real or perceived threat, it is best to retain the services of a licensed professional pest control operator to handle the problem.
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©1999 Darwin K. Vest, Eagle Rock Research