Dealing with silverfish can be a real pain in the you-know-what, both for homeowners and for pest control professionals working hard to provide some reasonable level of relief. On the bright side, silverfish are not considered particularly harmful to humans, as they do not bite or sting, but they can cause damage by chewing holes in certain fabrics, upholstery, wallpapers, books, and other items in the home.
Most of the time, high populations of silverfish inside a building are associated with higher than normal moisture concentrations in an environment, and remedial measures should always begin with this in mind. Attempting to treat for silverfish without identifying and correcting any potential sources of moisture is almost certain to be met with substandard results. As a general rule, silverfish thrive in warm environments with a relative humidity higher than 70%. Because of this, it is common to find them in areas such as bathrooms. Upon discovery of silverfish, take some preliminary moisture and humidity readings in various locations of the home, and make sure there are no significant structural deficiencies such as leaks that need to be corrected. Once that has been ruled out, begin efforts to reduce the relative humidity through use of dehumidifier units. By bringing down the moisture content, the home will become less hospitable for silverfish habitation. Also be sure to reduce old books and items stored in boxes in areas where silverfish have shown to be present.
After the moisture conditions have been assessed and addressed, silverfish treatment efforts can begin. Silverfish place packs are easy to use options that can be simply placed in various out of the way locations such as beneath sinks and under cabinets where silverfish are likely to take harborage. Around plumbing penetrations inside wall voids, where moisture content is often at the highest levels, insecticide dusts such as Delta Dust might be an ideal silverfish treatment option.
Outside the building, heavily mulched areas or woodpiles adjacent to the home often serve as ideal habitats. Look to remove or relocate these items away from the structure, as silverfish are solid climbers and can easily work their way into attic areas above. A variety of pesticide concentrate sprays and / or pesticide granules have proven effective in exterior control of silverfish populations.
What Should You Do When You Discover Silverfish?
Inspect the impacted area.
Get a feel for how widespread the silverfish population seems to be, what parts of the building they may be in, and what items might be stored in those particular areas that could be contributing to their area.
Take moisture readings.
Consider an inexpensive moisture meter or protimeter so that you know which areas of the building have higher than normal moisture content. This information can help rule out the possibility of more serious plumbing or roof leaks as well as let you know where to place dehumidifiers.
Use dehumidifiers to reduce humidity levels.
The most critical part of any silverfish treatment program is mitigating the levels of relative humidity in the area. This is so essential that sometimes it is possible to resolve a silverfish problem without any chemical or pesticide intervention at all simply by reducing the moisture and vacuuming or trapping the remaining silverfish.
Begin treatment. When treating, remember that silverfish are likely to be hiding in damp, dark places such as inside wall voids, beneath cabinets, behind baseboards, and other out of the way areas. As a result, fogging or surface sprays are unlikely to have much of an impact. Get treatment into cracks, crevices, and voids, and consider using silverfish place packs and silverfish traps.
If at any point you feel lost in your search for silverfish answers, consider checking out our Ask Professor Pest Live Online Chat for immediate expert pest control assistance.