Pests and pest control in Milwaukee, WI

Pests to know in Milwaukee

• Rats and mice
• Mosquito
• Subterranean termites
• Emerald Ash Borer
• Multicolored Asian Lady Beetle
• Spongy Moth

Why each one matters here is cited in the sections below.

Termites in Milwaukee

Subterranean termites do occur in Wisconsin but are limited: a Forest Products Laboratory study found two termite species, both in the southern half of the state, at the northern edge of their range.^[6]

Invasive species reported here

• Emerald ash borer was first found in southeast Wisconsin in July 2008 and has since spread through the southern half of the state.^[8]
• Spongy moth caterpillars typically hatch in May in Wisconsin, feeding for five to six weeks before adult moths emerge in July.^[11]

Pests local experts flag

• Milwaukee rats especially favor spaces under garages and sheds, often burrowing beneath cement garage slabs. Residents can report rat problems to DNS at 414-286-2268.^[2]
• Multicolored Asian lady beetles have been recorded in large numbers in Wisconsin since 1994; UW Extension says exterior sprays work best in late September or early October.^[10]

Climate

Central Milwaukee (ZIP 53202) is in USDA plant hardiness zone 6a, where the average coldest winter night is -10 to -5°F.^[12]

Public agencies that handle pests

• In Milwaukee, a Department of Neighborhood Services inspector checks reported rat infestations and can order the property owner to abate the problem or hire an exterminator.^[1]
• The Culex mosquitoes that spread West Nile virus are found in every Wisconsin county, including Milwaukee County, according to the state health department.^[4]
• Lyme disease is the most common tick-borne illness in Wisconsin, and the ticks that spread it are found in every county of the state.^[5]

Local rules and responsibilities

Milwaukee requires lumber, boxes and similar materials to be neatly piled at least one foot above the ground to deny rats harborage.^[1]

Hiring a licensed company

• Wisconsin pest control businesses, including sole proprietors, must hold a commercial pesticide application business license from DATCP, renewed annually.^[7]
• Wisconsin certifies termite work separately: the general structural category (7.1) excludes mosquitoes and termites, which require the Termite Control category (7.3).^[7]

Licensing agency: Wisconsin Department of Agriculture, Trade and Consumer Protection — Bureau of Agrichemical Management^[13].

See also how to check a pest control license.

Free local help

The UW Insect Diagnostic Lab, founded in 1978, identifies insects, spiders and other arthropods from around Wisconsin, though homeowners are encouraged to check with their county extension office first.^[9]

Through the year

Spring to Fall

Milwaukee's DNS baits active public areas such as sewers from May through September, when rodent activity is highest.^[1]

Summer to Fall

The Milwaukee Health Department notes human West Nile virus infections can occur from June through October, with most illnesses reported in August and September.^[3]

Sources

1. City of Milwaukee Department of Neighborhood Services, “Pest Control.” city.milwaukee.gov/Env/Pest-Control.htm (accessed 2026-10-06)
2. City of Milwaukee, “Be On Alert For Rat Problems.” city.milwaukee.gov/BeOnAlertForRatProbl15426.htm (accessed 2026-10-06)
3. City of Milwaukee Health Department, “City of Milwaukee Health Department Urges Residents to Prevent Mosquito Bites Following West Nile Virus Detection.” city.milwaukee.gov/Health/News/2026-News-Releases/July-2026/City-of-Milwaukee-Health-Department-Urges-Residents-to-Prevent-Mosquito-Bites-Following-West-Nile-Virus-Detection (accessed 2026-10-06)
4. Wisconsin Department of Health Services, “West Nile Virus.” www.dhs.wisconsin.gov/mosquito/wnv.htm (accessed 2026-10-06)
5. Wisconsin Department of Health Services, “Lyme Disease.” www.dhs.wisconsin.gov/tick/lyme.htm (accessed 2026-10-06)
6. USDA Forest Service, Forest Products Laboratory, “Genetic Analysis of Termite Colonies in Wisconsin.” research.fs.usda.gov/treesearch/48731 (accessed 2026-10-06)
7. Wisconsin Department of Agriculture, Trade and Consumer Protection, “Structural Pesticide Applications Compliance Checklist.” datcp.wi.gov/Documents/HTCStructural.pdf (accessed 2026-10-06)
8. University of Wisconsin-Madison, “Emerald Ash Borer in Wisconsin.” eab.russell.wisc.edu/2013/12/09/welcome/ (accessed 2026-10-06)
9. University of Wisconsin-Madison Department of Entomology, “UW Insect Diagnostic Lab.” insectlab.russell.wisc.edu/ (accessed 2026-10-06)
10. University of Wisconsin-Madison Extension, “Multicolored Asian Lady Beetle.” hort.extension.wisc.edu/articles/multicolored-asian-lady-beetle/ (accessed 2026-10-06)
11. University of Wisconsin-Madison Extension, “Spongy Moth.” hort.extension.wisc.edu/articles/spongy-moth/ (accessed 2026-10-06)
12. USDA ARS and PRISM, via phzmapi.org, “Plant hardiness zone for ZIP 53202 (2023 USDA map data).” phzmapi.org/53202.json (accessed 2026-10-06)
13. National Pesticide Information Center, “State Pesticide Regulatory Agencies.” npic.orst.edu/reg/state_agencies.html (accessed 2026-10-06)