It usually starts at the door. A spider web in the corner of the frame, a line of ants under the threshold, a cluster of boxelder bugs on the warm side of the house in October. Spraying around the doors seems like the obvious fix, and it can help, but only if you understand what door spray can and can’t do.
Here’s what actually works around doors in Treasure Valley homes, what doesn’t, and how to keep bugs from using your entryways as their front door.
Why Bugs Come In Through Doors
Doors are the biggest openings in a house, and they open dozens of times a day. Even when they’re closed, worn weatherstripping, a gap under the sweep or a cracked threshold can leave space for ants and spiders to squeeze through. Porch lights draw insects at night, and spiders follow the insects. In fall, boxelder bugs and stink bugs gather on sunny walls and slip in around frames looking for a warm place to spend the winter.
What Pests Show Up at Boise Doors
- Spiders. Webs in door corners, under porch lights and along the frame, especially in late summer and fall. Our spider identification guide covers the common ones.
- Ants. Pavement ants and odorous house ants following trails along the foundation and under thresholds. See our ant identification guide.
- Fall invaders. Boxelder bugs and stink bugs on sun-facing walls and doors.
- Wasps. Paper wasps building small nests in the top corners of door frames and porch ceilings.
What Door Bug Spray Can Do
Most products sold for doors and entryways fall into two groups:
Contact sprays
These kill bugs you hit directly. They’re fine for a single spider on the frame or a wasp at the porch light, but they leave little behind once they dry.
Residual sprays
A residual product leaves a treated band that keeps working on bugs that cross it for a period of time, depending on the product, the surface and the weather. Around doors, a residual applied along the threshold, the bottom of the frame and the foundation next to the door is what gives you some lasting protection.
What Doesn’t Work
- Spraying only inside the door. By the time bugs are inside, you’re treating the symptom. Most of the useful work happens outside.
- Spraying once and forgetting it. Sun, rain, sprinklers and foot traffic wear treatments down. Idaho summers are hard on anything applied to concrete and siding.
- Spraying over gaps instead of sealing them. A residual can’t make up for a missing door sweep.
- Heavy spraying of porches and walkways. More product isn’t better. It wastes product and puts it where people and pets walk.
Where to Apply It Around a Door
If you treat doors yourself, follow the product label every time. The label tells you where a product can go and how to apply it, and the EPA’s guide to pesticide labels explains how to read one. In general, the useful spots are:
- The outside threshold and the crack where it meets the slab or step
- The bottom few inches of the exterior door frame
- The foundation on either side of the door
- Around porch light fixtures and the eaves above the door, where spiders build webs
- The track and frame of sliding patio doors, a common gap for ants
Seal the Door, Then Treat It
Sealing does more long-term good than any spray:
- Replace worn or flattened weatherstripping
- Add or replace door sweeps so there’s no daylight under the door
- Caulk gaps around the frame and where the threshold meets the floor
- Repair torn screens on screen doors and sliders
- Switch porch lights to warm or yellow bulbs, which tend to attract fewer insects
- Keep firewood, stored items and dense plants away from the doorway
Don’t Forget the Garage Door
Garage doors are often the biggest gap on the house. The rubber seal along the bottom wears and cracks, and the sides of the door rarely seal tightly. Spiders and ants move in, and in fall, mice look for a way in too. If your garage is busy with spiders, our post on spider control for garages walks through it.
Why Professional Treatment Lasts Longer
A professional exterior treatment goes beyond the doorway. A technician treats the foundation, door and window frames, eaves and other entry points around the whole house, knocks down webs, and points out gaps worth sealing. Treating the full perimeter on a regular schedule keeps the protective band in place as weather wears it down.
Spiders, ants and wasps are all part of our residential pest control, with quarterly, bi-annual or one-time service. Quarterly service plan customers get free return visits. There are no contracts; you can cancel with 30 days’ notice.
Local Help With Pests at the Door
ProGuard is based in Eagle and serves Boise, Meridian, Nampa, Caldwell, Star, Middleton, Emmett and Garden City. Learn more about quarterly pest control in Boise, call us at (208) 352-2062 or send us a message to set up service.