Control Solutions Inc.: Spiders

By Marie Knox, PCO Technical Services Manager
Spiders are beneficial arthropods in that they prey upon and eat insects (among other pests); however, this fact does little to convince homeowners that they should share their residence with these eight-legged uninvited houseguests. While knowing a pest management professional (PMP) is on the job might help some homeowners to sleep better at night, it is vital that you communicate with your customer and get their cooperation during and after their “spider crisis” has been resolved.

Spiders are hunters, namely hunting insect pests in and around a structure. Not all spiders spin webs to catch prey. Some are active hunters that actively pursue their prey, while others are passive and wait for prey to approach close enough to capture.
Spider management and control can be tricky, but if we think about their hunting characteristics and where they’re most likely harboring, we can devise better treatment techniques and make better product choices when product application is warranted.

An integrated pest management (IPM) approach begins with the identification of the pest and inspection of the surroundings to determine conducive conditions, as well as potential harborage areas and food sources. A preferred habitat for spiders is an undisturbed environment with a food source (insects). This is where a homeowner’s habits can make or break your spider control efforts. Communicate upfront with your customer and let them know what steps they can take to make their homes less spider friendly. Clutter inside and outside of a structure not only creates a favorable harborage, but can also make treatment difficult. Removing clutter inside the home (in closets, playrooms, cabinets, bookshelves, etc.) and outside (moving wood plies and debris away from the structure, trimming landscaping, etc.) helps to reduce the number of places spiders can live and hide. Regularly “disturbing” spider habitats by moving furniture when cleaning, rotating items regularly in closets and on shelves, and reducing the accumulation of “stuff” in the garage can also help in making a structure less desirable for spiders.

Web dusting/removal can be helpful, and it is important to involve your homeowner in the management and control of spiders, including encouraging them to remove any webs they find in between your scheduled visits. A vacuum is a great tool that most homeowners have, and they can use it to remove webs, spiders and egg sacs without even having to touch them. Ask them to dispose of the bag or empty the canister into a bag, seal it tightly and place it in an outside trash bin immediately afterward. Webs can be found in many places, including around doors, windows, eaves, corners of ceilings, and under and behind furniture. Removing the webs disturbs the spider’s environment.

Spiders tend to return to the same area to rebuild their webs, so applying a product labeled for the site once the webs are removed can offer effective control when the spider returns. Water-soluble powders and dusts, as well as encapsulated formulations of repellent chemistries like pyrethroids, work well for spider control — especially on porous surfaces inside and outside of a structure. Always make sure to read and follow the label, and check in with the manufacturer as well as your state regulatory officials if you have questions.
When dealing with non-web spinning spiders like wolf spiders, focus on quiet undisturbed locations, around doors and windows and inside cracks and crevices.

Excluding spiders by repairing screens, sealing potential entry points and installing weather stripping on doors can also help keep the spider population indoors to a minimum. Outside, redirect lighting and/or replace outdoor bulbs with yellow bulbs that are less attractive to insects.

Keep in mind that spiders are feeding on insects, so inspecting the structure inside and out for insect pests and treating to reduce insect populations is a good step in reducing the spider’s food source, and therefore the spider population at a given structure.