Editor’s note: August is PCT’s annual rodent control issue, featuring a variety of rodent control articles from leading experts. In the following online extra from Site One, learn mice infestation signs and control methods.
Rodent Control
As temperatures cool, mice and rats begin to look for warm winter shelter. According to the National Pest Management Association, or NPMA, around 21 million homes are invaded by rodents each winter. Be sure to protect customers’ homes and businesses with preventative pest management for happier customers and routine business. All the rodents discussed in this article are found in the United States.
Signs of Mice Infestation
Signs of infestation are similar across the species discussed below. Gnaw marks and droppings are some of the most common signs. Droppings could either be soft and moist or dry and hard. Depending on the species, they could be rod or capsule shaped. Rodents can also leave oily rub marks on the walls from their fur, as well as footprints. The tracks typically have four toed footprints with front feet and five toed prints with back feet.
Rodents also tend to create burrows in nesting materials, such as insulation. Customers may notice noises in the attic or house walls, runways with stacked food, damaged food goods and damaged electrical wires. Of course, if a customer sees a mouse or rat, there are more out of sight. If there is a large infestation, customers may smell the odor of mouse urine.
Deer MiceDeer mice have bi-colored tails that are usually half brown and half white. Their bodies are round and brown, with white feet and underbellies. They typically grow five to eight inches long. This species feeds at dusk and dawn, eating insects, seeds, nuts, berries, and small fruits.
Deer mice prefer to nest in natural areas, like old fence posts, tree hollows and log piles. This species is rarely a problem residentially but may come indoors during winter months for shelter and food and can become a problem for agricultural customers. They can be found in sheds, barns and cabins.
These mice carry a significant health threat because they carry Hantavirus. This is transmitted through inhalation of dust particles that are contaminated with urine, feces or saliva of infected deer mice and can potentially be fatal.
House Mice
House mice are another typical species that cause infestations as they reproduce quickly. Most of the time this species is a dusty gray with cream-colored bellies. However, their fur can range from light brown to dark grey depending on location. They have round shaped bodies, pointed muzzles and large ears. Body length ranges from 2.5 to 3.75 inches long, but tails are extra 2.75 to4 inches long. The house mice diet consists of seeds, but will eat insects, nuts and fruit as well.
When they’ve found their way inside a building, house mice eat almost any human food, but prefer grains. They pose a health threat because they can contaminate food and spread diseases like salmonella, tapeworms and the plague. House mice are also excellent climbers and can jump up to a foot high. They can cause property damage by chewing through electrical wires. They prefer nesting in dark, secluded areas within structures. House mice have poor vision and are colorblind, so their other senses are heightened.
Deer and House Mice Control Tactics
To prevent these pests from coming inside, install door sweeps and repair damaged screens. Screen vents and openings to chimneys. Seal exterior cracks and holes, including where utilities and pipes enter the home (caulk, packed steel wool or a combination of the two). There should be no holes larger than a dime and no gaps wider than a pencil anywhere. Replace loose mortar around basement foundation and windows and eliminate all moisture sites, including leaking pipes and clogged drains. Keep shrubbery trimmed back from the house. Ensure proper drainage at foundation of buildings. Always install gutters or diverts that channel water away from building.
As a precaution against disease, always use heavy gloves and protective breathing gear when working in an area populated by deer mice.
Norway Rats
Norway rats are known as the common sewer rat and originated from Asia before spreading across the world. While this species also has poor vision and are colorblind, their other senses are keen. They aren’t incredibly agile, but can run, jump, climb and swim. Their bristly fur is brown with scattered black hairs, with a gray and white underbelly. Norway rats have small eyes and ears with tails that are shorter than their head and body together. They are long and heavily bodied with blunt muzzles, and typically span seven to nine inches long.
Norway Rat Control Tactics
Norway rats are drawn to piles of wood, so have customers store firewood well away from any structures. Remove all debris piles from the lawn to reduce nesting spots. Seal all holes on the outside of the home or building with steel wool to block potential points of entry. To discourage rats from looking for a water source, eliminate all moisture, such as leaky pipes. Encourage customers to seal all food products to avoid contamination and disease transmission. Ensure customers seal garbage cans and encourage them to regularly empty them outside the home to avoid attracting rats.
Roof Rats
Smaller than the Norway rat, roof rats have six to eight inches of body length and six to eight inches of tail. Their fur is brown with black mixed in and can have gray, white or black bellies. They are long and thin with a scaly tail and large ears and eyes. They are also known as the ship rat, as these rats are excellent swimmers.
Roof rats are originally thought to be from South Asia but are now found worldwide. In the U.S., they’re found on the coast as well as in the south. These rats live in colonies and prefer to nest in the upper parts of structures or in trees. Roof rats can spread disease. Historically, they’ve spread the plague, but there have also been some cases of typhus, jaundice and other diseases spreading also.
Roof Rat Control Tactics
Clean up fruit that falls off trees in customers’ yards. Ensure customers store garbage tightly and that it is covered. Seal up any holes larger than a quarter with silicone caulk and ensure windows and vents are screened properly. Keep trees and shrubs away from structure and cut back limbs overhanging the roof. Ensure customers are sealing their food in tight containers. Eliminate outdoor sources of water like leaky sprinkler heads, pet water dishes and birdbaths.
Trap placementPlace traps and put down bait as a preventative measure as the weather cools. As with all pests, have customers call you with any infestation concerns quickly, as rodents reproduce quickly and problems can escalate.
