Are hobo spiders dangerous in Montana homes?
MSU Extension says there is no conclusive evidence that hobo spiders harm people. They are a nuisance that many homeowners want removed, and the treatment should be planned around where they live rather than around a fear of bites.
A spider bite is never welcome, and anyone who is bitten and has symptoms should seek medical advice. But the research on hobo spiders does not establish that they cause serious harm, and a calm, targeted plan is more useful than an aggressive one.
The practical concern for most homeowners is the number of spiders in the lower level and the webs in the window wells. Those are the things the inspection is built to find and reduce.
When are spiders most likely to show up in basements?
MSU Extension reports that hobo spiders are prevalent in Montana basements, lower levels and window wells from August through November. That window is when a treatment or a sealing check is most useful.
As the weather changes, spiders and the insects they feed on move toward the building. Basements and window wells are sheltered and cool, which suits them. A visit in late summer lets the technician treat the wall edges and the well before the peak.
Outside that window, spiders can still be found indoors, but the timing of the MSU Extension research gives the clearest guide for planning. The technician will set a schedule around it.
How do I reduce the insects that bring spiders indoors?
Spiders follow their prey, so reducing insects around the house reduces spiders too. Light near doors, standing water, leaf litter and clutter against the foundation all draw insects and the spiders that eat them.
Turn off exterior lights you do not need, especially those near basement doors and window wells. Keep leaf litter, grass clippings and firewood away from the foundation wall, because they shelter insects and spiders.
Clear debris out of window wells every few weeks in the fall. A clean well gives spiders less cover and makes webs easier to see.
What does a treatment involve and what does it cost?
A treatment targets the wall edges, window wells and voids where spiders live, applied as the label directs. The price depends on the size of the lower level, the number of wells and the spread of activity, and is approved on site before any work.
The technician will mark the areas to be treated and explain what product class is used. A home with one window well and a small basement is a small job. A house with several wells, a long foundation and a crawl space takes more time.
No price is quoted on this page. The figure is set on the visit, after the technician has seen the activity, and you approve it before any treatment begins.
What should I do with spider webs and egg sacs?
Remove webs and egg sacs with a vacuum or a broom, and dispose of the contents outside. Avoid crushing spiders by hand, and keep the area ventilated if you use any cleaner.
Vacuuming webs and sacs removes the spiders and the eggs in one step. Empty the vacuum outside, or the spiders can return through the house. This is also the first step MSU Extension recommends for many fall insects that come indoors.
Once the lower level is clean, the technician can see fresh webs and activity more clearly. That helps the follow-up visit decide whether the plan is working.
