Guides
Ants, wasps, mice, black widows, earwigs, boxelder bugs and crickets — the seven you'll actually meet in a Tri-Cities home, with the month each one arrives.
7 min read
The common pests in Kennewick aren't the ones on national pest control websites. We're in a high desert at the confluence of three rivers, surrounded by irrigated farmland, and that combination produces a specific and fairly predictable line-up. Here are the seven you'll actually meet, and when.
Seven of the common pests in Kennewick account for the overwhelming majority of calls across Kennewick, Pasco, Richland and West Richland: odorous house ants, yellowjackets and paper wasps, house and deer mice, black widow and giant house spiders, earwigs, boxelder and stink bugs, and field crickets. Each has its own month, and most arrive on a schedule you can plan around.
| Pest | Peak months | Why then |
| Ants | May–August | Colony growth, then indoor water-seeking in the heat |
| Wasps | Mid-Aug–Sept | Max colony size and the switch to hunting sugar |
| Rodents | Sept–November | Harvest removes cover and food from the fields |
| Spiders | Aug–October | Mature males wandering to find mates |
| Earwigs | June–August | Irrigation and mulch; they follow moisture |
| Boxelder / stink bugs | Sept–October | Massing on warm south and west walls before winter |
| Crickets | Aug–September | Adults maturing in dry ground and moving to light and warmth |
Our number one call. Small, dark, and they smell faintly sour when crushed. The local twist: in July and August they come indoors for water, not food, which is why immaculate homes get them under sinks, behind dishwashers and in bathrooms.
The critical mistake is spraying a visible trail. Repellent sprays cause colonies to bud into satellites, so one trail becomes several. Use bait, or a non-repellent product, and accept that it takes a week.
Full detail, with prices: Ant Control in Kennewick: 7 Honest Cost Facts.
Not a July problem here — a late-August one. Colonies hit maximum size in late summer and simultaneously switch from hunting protein to hunting sugar, which is the moment they start bothering people at barbecues. Harvest season and backyard fruit trees make it worse across Richland and West Richland.
Paper wasps build open umbrella nests under eaves and are fairly docile. Yellowjackets nest hidden — underground, in rock landscaping voids, inside wall cavities — and those are the ones worth calling about rather than poking.
The full calendar: Wasp Control in Kennewick: 6 Proven Timing Rules.
Rodent season here tracks the harvest, not the thermometer. From late September through November, fields come off across the Columbia Basin and a large rodent population loses cover and food within a couple of weeks. Homes on the agricultural edge — the Road 68 and Broadmoor corridors, newer streets along Badger Mountain South, anything backing onto a canal — see it first.
One genuinely important local note: eastern Washington has deer mice, which can carry hantavirus. Never sweep or vacuum droppings dry — wet them with disinfectant first. Full method: Rodent Control in Kennewick: 8 Simple Warning Signs.
Most spiders here are harmless and useful, and most "spider treatments" are less effective than a broom. De-webbing eaves and corners, vacuuming, and switching bright white porch lights to warm-toned bulbs does more than any spray, because you're removing the insects the spiders came for.
Black widows are the real exception and they are genuinely common across the Tri-Cities: in rock walls, stacked landscape block, meter and irrigation boxes, under patio furniture, and in garages. Glossy black, round-bodied, with a messy tangled web at ground level and often a red hourglass underneath. If you're finding them repeatedly somewhere your family uses, treat that properly.
The pincered insects in the bathroom sink every June. They're a moisture pest, which makes them an irrigation pest here — they live in mulch, under landscape fabric, beneath river rock and in damp bark right against the foundation, then come in through the sill plate and door thresholds.
They don't harm anything and they don't infest a house, but they're deeply unpopular. The fix is almost entirely mechanical: pull mulch back from the foundation, water in the early morning so beds dry during the day, and fit door sweeps.
Every September and October they appear in dozens on the south and west walls of homes, sunning themselves before overwintering. They don't bite, don't breed indoors, and don't damage anything — but they stain surfaces when squashed and stink bugs earn their name.
Spraying a wall covered in them is mostly theatre. What works is sealing before they arrive: window and door weatherstripping, screening attic and gable vents, and closing gaps around utility penetrations in August. Once they're inside a wall void, vacuuming is the honest answer.
Late summer brings them out of dry ground toward warmth and light, into garages, window wells and under doors. In a dry year they can be dramatic, and the noise alone drives people to call.
They're a perimeter and lighting problem, not an indoor one. Exterior lights on the far side of the yard, sealed garage door seals, and a treated foundation perimeter handles it.
Three local conditions explain nearly all of it.
None of that costs anything meaningful, and against the common pests in Kennewick it outperforms most products you can buy. If you'd rather it was handled on a schedule, the Home Pest Protection Plan covers all seven of these — $149 for the first visit, then $59–109 a month by home size, with free re-service between visits.
Not sure what you're looking at? Call (509) 222-9828 and describe it, or get a free quote. Where DIY genuinely wins is laid out honestly in Pest Control in Kennewick: 5 Honest DIY vs Pro Calls.
Not in the main seven, but they come up often enough across Kennewick, Pasco and Richland to be worth recognising.
Two things we do not have much of, despite what national sites imply: subterranean termites are uncommon in this part of Washington compared with the South and Southwest, and bed bugs, while they certainly exist here, are a travel and second-hand furniture problem rather than a regional climate one.
For identification and non-commercial treatment guidance specific to our growing region, Washington State University's Hortsense is the best free resource available and it isn't trying to sell you anything. For anything involving pesticide safety around children, pets or food, the EPA's Citizen's Guide to Pest Control and Pesticide Safety is worth reading before you buy a product off a shelf.
Odorous house ants, by a wide margin, peaking May through August. In midsummer they're usually indoors looking for water rather than food, which is why clean homes get them too.
Yes. They're established throughout the area in rock walls, landscape block, meter boxes, garages and under outdoor furniture. Bites are rare because they're not aggressive, but they're worth treating where children play.
Late September through November, following harvest rather than cold weather. Homes near fields, canals or undeveloped land see the first wave.
The pests change by season rather than stopping — ants in summer, wasps in late summer, rodents and overwintering bugs in autumn. Quarterly service targets whatever's active at that point in the year.
Irrigation, mostly. In a landscape this dry, a watered lawn and damp foundation bed are the wettest thing for a long way, and that's what concentrates insects at your walls.
Mostly no. The exceptions worth respecting: black widows, yellowjacket stings if anyone is allergic, and deer mice, which can carry hantavirus — never sweep or vacuum their droppings dry.
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