Pest Control for Kendall County's Young Subdivisions and Old River Towns

The decade Kendall County doubled

Between the 2000 and 2010 censuses, Kendall County went from about 54,500 residents to about 114,700, an increase of roughly 110 percent that made it the fastest-growing county in the United States for that decade. Oswego more than doubled, from about 13,300 to about 30,400, after already tripling during the 1990s. Yorkville went from about 6,200 to about 16,900. Plano added new neighborhoods on its north and south sides during the same years.

That pace explains nearly everything about the local pest picture. A large share of the county's homes are less than thirty years old, built in large phases on graded farmland, and many of them back directly onto fields that are still farmed. Instead of the alley rats and shared-wall cockroaches of older suburbs, Kendall homeowners mostly deal with animals that lived on the land before the houses arrived and the insects that thrive in young landscaping. The county is less a collection of old towns than a string of new neighborhoods hung around three small historic cores. Building also continues: farm parcels on the edges of Yorkville and Oswego are still being platted, so the boundary between cornfield and backyard keeps moving, and with it the line where fall mouse pressure is heaviest.

Where field mice get into a new two-story home

The typical Kendall County house is a two-story with a poured concrete basement, a sump pit, an attached two- or three-car garage, vinyl siding and ridge and soffit vents. It is tighter than a 1920s farmhouse, but it still has predictable openings. The most common is the garage: bottom seals on overhead doors flatten and split within a few winters, and the gap at the corners where the door meets the jamb is often wide enough for a deer mouse. From the garage, mice reach the house through the gap around the door to the mudroom or the unsealed penetration where the water heater vent or gas line passes through.

Other routes include air-conditioning line sets and outdoor faucets where the hole in the rim joist was drilled larger than the pipe, dryer vents without guards, and weep gaps at the base of brick or stone veneer on front elevations. In finished basements, mice travel the space between the foundation wall and the framed wall, unseen, and come out at outlets or under stairs. Deer mice, common at the field edges, nest in stored boxes, insulation and the cavities under bathtubs. Because deer mice can carry hantavirus, public health guidance is to ventilate, wet down droppings with disinfectant and avoid sweeping or vacuuming them dry.

The harvest calendar indoors

Rodent pressure in Kendall County runs on the farm calendar more than the thermometer. Through the summer, field mice and deer mice live in the corn and soybeans that still surround Yorkville, Plano and the western edge of Oswego. When combines start running in late September, cover and food disappear within days, and the mice move to the nearest structures: barns, sheds and then the garages and basements of the first row of houses.

That is why a homeowner on a street facing open fields often sees a sudden spike in October while friends a mile inside the subdivision see little. The surge usually tapers by December, but mice that got in during harvest will breed indoors all winter if they are not removed. The most effective approach is timed: a sealing visit in late summer, followed by monitoring and trapping as harvest begins. Bait stations outside garages can help in rural settings, but they should be tamper-resistant and placed where pets and children cannot reach them. Spring planting brings a smaller second wave in April and May, when tilling disturbs nests along field margins and some mice shift into sheds and window wells before the crop canopy closes.

New sod, mulch beds and detention ponds

Construction leaves its mark on the soil. Builders strip the topsoil, compact the lots and lay sod or seed over a thin layer of fill, and the deep prairie soils beneath are full of earthworms and grubs. Eastern moles find that combination ideal and push ridges and mounds across new lawns, especially after spring rains. A new lawn can show fresh runs within weeks of the sod going down, and the damage often follows irrigation lines and the edges of beds where the soil stays soft. Striped skunks dig small cone-shaped holes hunting the same grubs, usually at night in late summer and early fall.

Young landscaping beds of fresh mulch hold moisture against the foundation, and that is where pavement ants, earwigs, millipedes and sowbugs build up. Paver patios and the sand beneath them are favorite pavement ant nesting sites, and small piles of sand between the joints in spring are the clue. Most subdivisions also manage runoff with detention and retention ponds. Those ponds attract raccoons, skunks and Canada geese, keep mosquitoes and midges abundant around back patios and give spiders plenty of prey near outdoor lights. Homes that back onto a pond usually see more spiders on siding and soffits than homes across the street.

The Fox River diagonal and the creeks that feed it

The Fox River enters Kendall County from the northeast near Montgomery and Oswego and cuts diagonally southwest through Yorkville toward Millbrook before leaving for LaSalle County. Wooded banks follow it most of the way. Waubonsee Creek meets the river in Oswego, Blackberry Creek comes in near Yorkville, and Big Rock and Little Rock creeks drain the countryside around Plano. Aux Sable Creek drains the eastern part of the county toward the Illinois River.

Each of those streams is a wildlife road between farm fields, woods and backyards. Raccoons and opossums follow the banks into neighborhoods, big brown bats roost in older homes near the water and forage over it at dusk, and gray and fox squirrels spread from the riverside woods into street trees. The river floods in wet years, and its floodplain near Plano holds the famous Farnsworth House, which has been flooded several times. Homes on low ground near the creeks see wet basements and the centipedes, millipedes and silverfish that come with them. A sump pump that cycles often during wet weeks is an early sign that the lower level will need attention for moisture pests.

A small preserve district with long edges

Kendall County's forest preserve system is modest in size, about 26 preserves totaling just under 3,000 acres, but much of it sits on the river. Hoover Forest Preserve, west of Yorkville, runs nearly a mile along the Fox with a trail network through woods and bluffs, and Fox River Bluffs adds about 168 acres nearby. Subat, the Ellis House and Equestrian Center in the southeastern part of the county, and several smaller sites round out the district. The state's Silver Springs State Fish and Wildlife Area, about 1,350 acres of woods, prairie, ponds and roughly three miles of river frontage, lies west of Yorkville toward Plano.

Because so much of that land is linear, its edges reach a great many backyards. Homes near the preserves and Silver Springs deal with raccoons, skunks, opossums and moles more often than residents of denser suburbs, and native snakes such as garter, brown and fox snakes appear in window wells and garages. They are harmless and protected in Illinois, so specialists relocate them and recommend well covers rather than killing them.

The older blocks: frame houses near the tracks and the river

Kendall County's historic housing is small in quantity but distinct in its problems. The original streets of Oswego above the river, Yorkville's blocks on either side of the Route 47 bridge and the neighborhoods around Plano's railroad depot hold nineteenth and early twentieth-century frame houses, a few brick homes and modest bungalows. Many have fieldstone, brick or early block foundations, open balloon-frame walls that run from basement to attic, and wood porches set close to the soil.

Those features create a different list from the subdivisions. Mice climb inside the wall cavities and are heard at night in second-floor bedrooms. Eastern subterranean termites find porch posts, sill plates and basement stair stringers, and their mud tubes show on stone or block walls. Big brown bats and squirrels use gaps around old roof boards and gable vents, and damp cellars keep house centipedes and silverfish going all year. A careful attic and foundation inspection every few years is worth more in these homes than in any new build.

Weather, regulation and what to expect from a visit

Open fields mean wind, and wind makes the cold feel sharper. Kendall County's first hard freezes, usually in October, push crickets, wolf spiders, boxelder bugs and multicolored Asian lady beetles toward the sunny south and west walls of homes, where they crawl in around window frames and siding gaps. Spring rains bring the opposite problem, saturating fill soil and sending ants and millipedes indoors through slab and foundation cracks.

Anyone applying pesticides in and around homes for hire needs a structural pest control license from the Illinois Department of Public Health, and anyone trapping raccoons, skunks or other wildlife needs a permit from the Illinois Department of Natural Resources. Many Kendall County subdivisions have homeowners associations that regulate fences, sheds and exterior changes, so check the rules before installing exclusion screening, chimney caps or bait stations on visible elevations. A first visit usually starts in the garage, then the basement rim joist and utility entries, then the attic vents. Prevention steps that suit the county's housing:

• Replace overhead garage door bottom seals and add corner pads before late September
• Seal air-conditioning line sets, gas lines, outdoor faucets and dryer vents with copper mesh and sealant
• Keep mulch thin and a few inches below siding, and pull it back from window wells
• Install clear window well covers, especially on homes facing fields, ponds or preserves
• Store grass seed, birdseed and pet food in sealed bins, not open bags in the garage
• Check that the sump pit lid fits snugly and that the pump discharges well away from the foundation
• Wet-clean any rodent droppings found in storage areas instead of sweeping them