Unseasonably Mild Winter Means Pest Pressure Could Rise This Spring

National Pest Management Association releases winter Vector Sectors™ list highlighting 10 U.S. cities most at-risk for increased pest populations

FAIRFAX, Va. – February 23, 2023 – The National Pest Management Association (NPMA) today released its bi-annual Vector Sectors™ list of the top 10 U.S. cities with the greatest risk for increased pest pressure from vector pests for the remainder of winter and into spring. With a few exceptions, much of the country has endured a relatively mild winter, and according to the experts, that can have a direct impact on tick and mosquito populations.

“People aren’t the only ones enjoying the warmer-than-average winter season this year,” said Dr. Jim Fredericks, Senior Vice President of Public Affairs for the National Pest Management Association. “These warm and wet conditions create the perfect recipe for pests like ticks, mosquitoes and cockroaches to get an early start to their peak season. Despite being a nuisance, these pests are capable of transmitting diseases to humans and pose significant threats to our health and well-being.”

The top 10 U.S. cities* named to the National Pest Management Association’s Vector Sectors list include:

Boston: Despite a warmer-than-normal start to the winter, rodent populations are high and will seek shelter indoors throughout the cold winter months.

Detroit: Mild weather in January and February means ticks will be seeking hosts for a blood meal on days when the temperature exceeds 50 degrees or more.  

Grand Rapids: A cold start to the winter increased pressure on rodents to seek shelter indoors, where they will remain. Warmer-than-average temperatures to finish out the winter will give ticks a head start on the spring season.

Harrisburg: Warmer-than-normal temperatures throughout the winter allowed tick populations to remain stable, which means more tick activity as weather warms in the late winter and early spring.

Indianapolis: Mild winter months equal larger proportions of overwintering tick populations surviving to spring. Beware of hungry ticks on warm winter and spring days.

Minneapolis: Cold temperatures drove rodents indoors early, but a relatively mild February will give tick populations a jumpstart on spring by increasing survivorship of overwintering ticks.

Miami: Warm and wet winter months are the perfect recipe for cockroach and mosquito populations to take off entering the spring. 

New York: A milder than usual winter will result in more ticks being active on warm days in the late winter and early spring.

Pittsburgh: Lower-than-normal snowfall totals coupled with mild winter weather means more ticks and increased activity on mild winter and spring days.

Salt Lake City: Cooler-than-normal weather early in the season drove rodents indoors where they will stay despite milder temps in January and February.

*Listed in alphabetical order, no numeric ranking.

“While a majority of the country observed mild conditions, a fair share of the U.S. did encounter significant snowfall and dry spells as well as below-average temperatures, securing their spot on our watchlist,” said Fredericks. “Dipping temperatures tend to drive rodents indoors, where they’ll find food and shelter to keep them busy until the spring weather rolls in.”

In addition to causing property damage, rodents are capable of spreading more than 35 diseases, including Salmonella and hantavirus, making it imperative to practice proper prevention to keep yourself and your family protected. While small in size, mice and rats can squeeze through openings in a structure the size of a dime and quarter, respectively, and are believed to invade an estimated 21 million U.S. homes each winter.  

To limit encounters with vector pests, NPMA encourages homeowners to seal cracks and holes on the outside of the home and practice keeping food in airtight containers. Be sure to dispose of garbage regularly and store firewood at least 20 feet away from the house. When spending time outdoors, wear long pants and sleeves when possible, along with bug repellent containing at least 20 percent DEET. Refrain from wearing fragrant perfumes and opt for light-colored clothing to make spotting ticks easier. Before heading indoors, thoroughly check clothing, skin and pets for ticks and promptly remove to limit exposure to tickborne disease.

If you suspect an infestation, contact a licensed pest control professional immediately.

For more information on NPMA’s Vector Sectors list, or to learn more about protecting against pests, visit PestWorld.org.

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About the National Pest Management Association

The NPMA, a non-profit organization with more than 5,500 members, was established in 1933 to support the pest management industry's commitment to the protection of public health, food and property from the diseases and dangers of pests. For more information, visit PestWorld.org or follow @PestWorld on Facebook, Twitter, Pinterest, TikTok and YouTube.