Spider control can stump even the most experienced pest management professional (PMP). Effective control, however, can be framed with six simple steps:
1. Identify. Other than cases involving medically significant spiders, it usually is not imperative to meticulously identify spiders down to the species level. Placing spiders into basic categories — cobweb weavers, orb weavers, funnel-web weavers, and wandering/hunting spiders — will suffice to give technicians adequate guidance in the field.
2. Investigate. For example, how and when did these spiders enter the structure? Are egg sacs, juveniles, adult males and females present?
3. Implement interior control. Eliminate the existing population. Usually a good flashlight, a cobweb duster and a vacuum are all you need.
4. Exclusion and perimeter application. Deter spiders from staging directly outside of a structure, which should include applying a long-residual pesticide dust into cracks, crevices and voids. The underside of eaves should be treated with a residual liquid application.
5. Manage prey. Note that spiders are opportunistic feeders, capable of surviving extended periods between meals. It is practically impossible to completely eliminate spider food sources, but you can make it a little harder for them.
6. Find and remove webs, spiderlings and egg sacs. Egg sacs protect eggs from pesticides. Look closely: Are eggs present or have spiders already hatched? This is probably the most critical tactic for long-term control — and too often forgotten. Once these tiny spiderlings hatch and disperse (usually in the hundreds and thousands), they can easily fit through the finest-mesh window screens, easily navigate the smallest cracks under siding, and simply enter beneath doors and windows that appear to be sealed airtight. After building their initial webs, spiderlings may rarely move for several weeks to months as they mature into adults, so they may not encounter residual pesticides at all.
Bonus tip: Remember to always time pesticide applications to take advantage of spider reproductive cycles.