As the weather warms from spring into summer, rodent activity across the Western U.S. is on the upswing. Whether you’re managing a food processing plant, grain storage facility, or warehouse, now is the time to be extra vigilant. At Sprague, we’re tracking pest trends year-round, and the data is clear: May through July—and again in the fall—are peak times for rodent pressure. Here’s what businesses need to know to stay ahead.
Rodent Trends by Industry and Geography
Rodents aren’t just a nuisance; they can severely impact your facility’s safety and compliance. Based on capture data from thousands of locations, we have found:
- Grain storage and seed facilities experience the highest pressure, averaging over 6,000 captures per 100 accounts annually.
- Food processing plants see significant pressure as well, averaging around 1,600 captures per 100 accounts.
- Idaho currently tops the list for rodent captures per account, particularly house mice—triple the rate of captures that we are seeing Washington.
Know Your Rodents
Understanding the species we’re dealing with is crucial to controlling infestations effectively:
- Brown Rat/Norway Rat (Ratttus norvegicus): These large rodents are consistent year-round and are especially common in Washington and Oregon. They have blunt muzzles, small ears, and short tails.
- Black Rat/Roof Rat (Rattus rattus): Harder to trap and most prevalent in California, roof rats peak in late summer. Look for their long tails and pointed muzzles.
- House Mice (Mus musculus): By far the most frequently captured rodent. Capture numbers spike in spring and fall but remain high throughout the year.
- Deer Mice (Genus Peromyscus): Common in the western United States, these can carry hantavirus, which makes proper identification critical. They’re distinguished by their two-toned, very hairy tails.
Effective Rodent Control: Best Practices
Rodent control isn’t a one-and-done fix—it requires a thoughtful, multi-faceted strategy. Rodents are intelligent and resourceful, seeking out warm, dark areas close to food and water.
That’s why inspections are so critical. Identifying harborage points—like behind equipment, inside wall voids, or near loading docks—helps guide precise placement of traps and bait stations. Snap traps remain one of the most effective tools, especially when clustered together in high-activity zones. Pre-baiting traps (placing them unset at first) helps rodents gain confidence, increasing your odds of a successful capture when the trap is eventually armed.
Using the right attractant is also key. Food isn’t always the best option—nesting materials like cotton or insulation can be irresistible, especially during breeding seasons.
In dry areas, moisture-rich foods like cucumber may be more effective, and even a local rodent dropping can help make a trap smell familiar (when allowed by facility policy).
Most importantly, we strive to set clear expectations with clients. Depending on the severity and nature of the infestation, full control may take several visits. Open communication about timelines, rodent biology, and control methods builds trust and leads to long-term success.