COVID-19 Spreads Rodents

Features - Pest Management

Juxtaposition of business booms and busts exacerbates seasonal issues.

October 12, 2020

photo by: Alexander Garrett

The cooling weather of fall and winter customarily brings increased rodent issues as rats and mice seek harborage from worsening conditions outdoors. But all expectations are that those rodent issues will be increased this year due to the COVID-19 pandemic. As the virus spread, foodservice and retail establishments closed down, and people’s behaviors changed, so too did the spread and behaviors of rodents.

“COVID-19 has been a huge disruptor of many of our normal routines in terms of pest management,” said P&M Pest Consulting Partner Myron Baumann. “We are seeing the impact of these changes in many forms, including rodent-feeding patterns, daytime activity, and even reproduction.” And this impact is being seen from D.C. to Seattle. (See From D.C. to Seattle, page 68.)

The cooling weather of fall and winter brings increased rodent issues as rats and mice seek harborage from worsening conditions outdoors.
© William Rob Casey | Adobestock

“The lack of human activity is probably the biggest change that will influence how rodents move and populate new areas,” Baumann explained. Less human activity will make the environment more attractive to rodents, allowing them to live and breed closer to plants. Reductions in building maintenance can result in additional harborage sites and “more or less access to food depending on the situation,” he said.

The lack of human activity is probably the biggest change that will influence how rodents move and populate new areas.

There seem to be two different extremes when it comes to rodent issues resulting from the pandemic’s impact on business, said McCloud Services Technical Director Patricia Hottel. “Some food facilities have seen a boom in business, and some have seen a decline in business, with temporary or permanent closures.” As such, she explained:

  • Buildings left vacant can be more prone to rodent and other pest issues, providing undisturbed areas to harbor rodents, potentially impacting their neighbors as well.
  • Those facing increased demand have less downtime for cleaning and maintenance, and decreased cleaning can equate to additional food availability for pests.
  • Increases in outdoor dining and food consumption can increase food availability for rodents in the form of food scraps or garbage.

Add to that the juxtaposition of the booms and declines which can further exacerbate rodent issues. “If a facility is in an area where food resources have decreased due to business closures, rodent pressures may increase at that facility as they seek new sources of food,” Hottel said.

“Under the right conditions, rodents can be quite prolific and build up rapidly,” she added. This is especially true for the common house mouse. Thus, if there are increased rodent pressures on the exterior of the facility, additional vigilance is required. “Additional monitoring of areas in anticipation of that potential activity surge is advised. Making sure areas are properly pest proofed is essential.”

“While we cannot control some of the rules and regulations put in place to help protect an increase in the outbreak, we still must manage rodents, and other pests for that matter, around food processing facilities,” Baumann said.

Rodents still follow the same basic rules they have for thousands of years — eat, survive, and reproduce, he said. But they have had to change their habits for feeding, survival, and reproduction, so “we must adapt to their habit changes to stay ahead of them with our control tactics.”

RODENT MANAGEMENT. This means inspecting, excluding, monitoring, and responding to trends, Hottel said. “Make sure employees are reporting any activity observed and performing thorough inspections of incoming shipments. Share pest sightings and incoming shipment findings with the pest management company and partner with the pest management professional to correct conditions conducive to pests.”

Effective two-way communication is essential, she said, especially when changes are made to the facility and surroundings due to the pandemic. For example, Hottel has seen an expanded use of outdoor areas for breaks and food consumption. So increased attention should be paid to how the surfaces are cleaned, whether trash receptacles are sufficient to handle the additional refuse, etc.

Baumann also sees increased communication as critical, with changes made to the pest service plan to reflect the additional pressure or different activity. “Most plants have a pest activity history to reference when dealing with rodent pressure, but current times call for adjusting on the fly to manage activity pattern changes,” he said.

Baumann recommends inspection of the exterior and interior and a review of plant practices and policies, to include:

To protect your facility against rodent entry, proactively adjust the pest control plan to meet the additional pressures presented.
© jaranjen | iStock
  • Inspect the exterior of the plant and surrounding properties for conducive conditions that support rodent populations. Food, water, and harborage are critical to rodent survival. Consider how reduced human influence may have allowed issues to develop. For example, a closed business may not have their regular lawn care service and tall grass may provide additional harborage.
  • Inspect the facility for potential areas of ingress with both a plant and pest control company representative working together to ensure the plant is well sealed.
  • Review plant practices and policies to ensure doors are being kept closed. As the weather cools the warmth around open doors and windows will attract rodents.
  • Proactively adjust the pest control plan to meet the additional pressures presented.

MONITORING FOR CONTROL. Additionally, Baumann said, rodent catches should be monitored; activity reported by location and numbers; reports compared against similar periods of the previous year; and the pest plan should, then be adjusted accordingly.

“Reading current data on captures and feeding at rodent bait stations will identify trends and where the rodent pressure is originating from,” he explained. “Depending on the size of the plant property, this data can call for significant changes in the pest control plan or minor tweaking to improve the plan.”

If the plant covers a large area, using monitoring stations where rodenticide cannot be placed will be a helpful tool to drive decisions for pest control plan changes. This could include more traps, rodent stations, or increased service frequency.

“Monitoring provides an opportunity to respond to what trends are telling us regarding population increases or decreases, Hottel added. This is important in the measuring of external populations, evaluating the control tools that are in place, and ensuring that the control tools and preventative programs are sufficient.

While there will be some increases in rodent populations due to fall harvest and cold weather, “the same rules apply to any increase in rodent populations,” Hottel said. “Inspect, monitor, exclude, and respond to what our monitors and inspections are telling us with the appropriate actions.”

“I think there have been rodent habit changes as long as I have been in the business,” Baumann said. “Recognizing the changes in a timely fashion is key to reacting and staying ahead of the problem.”

Communicate with your pest provider to ensure everyone is on the same page: if you are not seeing changes in rodent pressure, there is no need to change a proven plan. But if the pressure and activity has gone up at your plant, you need to complete a root cause analysis to determine why and adjust the plan to match the pressure, Baumann said.

“Rodents adjust quickly to leverage opportunities to have a better life and survive when things get tough,” he said. “Staying up with these changes — or even better adjusting to get ahead of them — is critical to a great pest control plan.”

The author is Senior Advisor and Former Editor of QA magazine. She can be reached at