Pests follow the cold
In Sioux Falls, the pest calendar is driven by winter. With a 99% winter design temperature of −11°F and a 50-year frost depth of 102 inches, mice and insects look hard for shelter each fall. Summers are drier than in the South, with NOAA counting about 232 hours a year above a 73°F wet-bulb, which limits some moisture-loving pests but not ants, wasps or mosquitoes. This checklist follows the seasons.
August and September: the most important month for prevention
- Seal the house before the cold. Mice can squeeze through very small gaps. Check where pipes, wires and dryer vents enter, and the gap under the garage door.
- Add door sweeps and fix weatherstripping.
- Screen vents and chimney openings.
- Clean up yard debris and woodpiles near the house.
October and November: fall invaders
- Watch for boxelder bugs, lady beetles and cluster flies gathering on sunny walls. Seal gaps around windows and siding where they get in.
- Vacuum invaders indoors rather than crushing them.
- Set traps in the garage and basement if you see signs of mice.
December through March: indoor watch
- Check pantries, under sinks and basements for droppings.
- Inspect stored items in the basement and garage.
- Keep firewood outside and bring in only what you will burn soon.
April and May: spring cleanup
- Look for nests in the garage, sheds and under decks.
- Repair winter damage to screens and siding.
- Check foundation cracks opened by frost heave, and seal them.
June through August: summer insects
- Watch for ant trails in kitchens and along foundations.
- Look for wasp nests under eaves and decks early, while they are small.
- Drain standing water to reduce mosquitoes.
Hiring a pest professional
In South Dakota, commercial applicators using pesticides in human dwellings must pass the general core exam and the Category 8 structural pest control exam, which also covers rodent and bird control in and around structures. Ask whether the technician has passed Category 8, and what products will be used inside the home.
What to ask before treatment
- What pest is it, and how did you identify it?
- What product, where, and how long until it is safe for children and pets?
- What sealing or exclusion work is included?
- Is there a follow-up visit or guarantee?
Keep a record
Note sightings, treatments and repairs. Patterns from year to year show where the house needs sealing.
Basements and window wells
Sioux Falls basements give pests a warm place to winter. Check window wells for gaps around the frames and keep them clear of leaves, where insects and small animals shelter. Look along the sill plate where the house sits on the foundation, a common entry point for mice. Seal small gaps with caulk and larger ones with materials mice cannot chew, such as copper mesh or sheet metal, before filling them.