November Animal - Wolf Spiders
University of Nebraska - Lincoln Extension Educator Dennis Ferraro is the resident herpetologist at the School of Natural Resources. Dennis writes timely articles on animals that you might see on your acreage in Nebraska, ranging from mammals to insects. This month Dennis covers wolf spiders, that may be increasing the fear factor in your home.
Wolf spiders are one of the most common spiders found across Nebraska. They usually elicit alarm and stress among homeowners because of their large size, quick movement, and hairy bodies. There are several different species of Wolf spiders in our area, so most people do not always recognize all of them as Wolf spiders. These spiders are harmless to people or pets. However, many people fear harmless spiders because of misunderstandings concerning danger. In reality, there are only a few species of spiders that warrant caution. Wolf spiders are a desirable part of the ecosystems in which they occur. They feed on insects, including species which are pests of plants, and nuisance species such as biting flies, as well as other spiders and scorpions. Therefore, these spiders are generally considered to be beneficial organisms.
Sanitation and habitat modification are key tactics for control of spiders indoors. This includes vacuuming in corners, window sills, and attic areas, and keeping the premises free of clutter such as undisturbed clothing, papers, and other litter. The corners and crawl spaces of buildings should be kept free of spider webs. This may be accomplished by simply dusting these areas or by using a vacuum to remove existing webs. Vacuuming removes active spider webs, adult spiders, and spider egg sacs. Living spiders will desiccate quickly in the vacuum bag, but depending on the design of the vacuum, it may be useful to empty the bag immediately after use in order to prevent the spiders' escape.
Removing litter such as newspaper and wood from the interior and the sides of buildings is also crucial for effective elimination of spiders. Pruning shrubbery and other plants away from buildings also will limit the access of spiders to buildings.
In addition to sanitation, creating a physical barrier to the movement of spiders into buildings is an effective management technique. Caulking, repairing screens, and filling cracks and crevices around windows, doors, and foundations with materials such as expanding polyurethane foam will exclude many spiders from buildings. Common areas to inspect for holes and gaps include entry holes for plumbing and electrical lines, and window and door casings. In window and door screens, repair any holes large enough for spiders to enter. Gaps in the wall boards and ceiling-wall interfaces should be closed, and door and window casings should be filled with caulking or a foam insulation material. Spiders can easily gain access to buildings through gaps beneath doors. Place a piece of weather stripping under a door so that there is no gap between the bottom of the door and the floor when the door is closed to alleviate this problem.
Foam insulation material can be used to fill wall voids and crawl spaces if spiders come in through these areas. If crawl spaces are a breeding area for spiders, the reason is usually excess moisture. By eliminating moisture from crawl spaces, spiders can be eliminated. Placing plastic over bare soil can eliminate moisture in some areas, such as beneath cabins. The key to solving many moisture problems is to increase venting. Therefore, opening ducts under a foundation may eliminate moisture from a crawl space, without allowing increased access of the building for spiders.
Precautionary measures to reduce the risk of being bitten by spiders include wearing shoes at all times, using leather gloves when moving rocks, wood, or other debris, and shaking out sleeping bags and clothing before using them. Chemical control of spiders inside of buildings is not recommended and should be considered only as a last resort. For reduction of large numbers of spiders indoors, room foggers containing pyrethrins/pyrethroids are helpful. Follow all label directions, as pesticides can be dangerous if used improperly.