Pests to know in Ann Arbor
Termites in Ann Arbor
HUD's FHA termite exception list exempts 46 Michigan counties, mostly in the north, from termite treatment for new construction. Washtenaw County is not listed, so treatment is required.[5]
Invasive species reported here
- MDARD reported that, as of September 2026, spotted lanternfly populations had been confirmed in eight Michigan counties, including Washtenaw.[6]
- Washtenaw County is one of the Michigan counties under MDARD's box tree moth quarantine, which stops boxwood plants and nursery stock from leaving the quarantined area.[7]
- Emerald ash borer, first found in Michigan in 2002, has killed tens of millions of ash trees statewide, and the state no longer asks residents to report it.[8]
Pests local experts flag
Ann Arbor forestry explains that sap-feeding beetles can carry the oak wilt fungus to fresh wounds on healthy oaks, and red oaks may die quickly once infected.[4]
Climate
Central Ann Arbor (ZIP 48104) is in USDA plant hardiness zone 6a, where the average coldest winter night is -10 to -5°F.[10]
Public agencies that handle pests
Local rules and responsibilities
Ann Arbor's city ordinance prohibits pruning or trimming oak trees from March 1 through December 1, whether the tree is on private property, public property, a utility easement or the right of way.[4]
Hiring a licensed company
Businesses that apply pesticides for hire in Michigan need an MDARD pesticide application business license, which expires every December 31; individual certification alone does not cover running such a business.[9]
Free local help
MDARD says it works with Michigan State University Extension on spotted lanternfly, and MSU Extension asks growers to report detections through the DNR's Eyes in the Field tool or a local MSU Extension office.[6]
Through the year
- Spring to Fall
- In a release on local mosquito testing, Washtenaw County Health Department said most Jamestown Canyon virus cases occur from late spring through mid-fall.[3]
- Spring to Summer
- Ann Arbor's forestry page notes that the Michigan DNR treats April 15 through July 15 as the highest-risk window for oak wilt infection in the state.[4]
Sources
- Washtenaw County Health Department, “Lyme Disease & Ticks.” www.washtenaw.org/lyme-ticks (accessed 2026-10-06)
- Washtenaw County Health Department, “Rabies.” www.washtenaw.org/rabies (accessed 2026-10-06)
- Washtenaw County Health Department (via Lyndon Township), “Mosquito-Borne Illness: Jamestown Canyon and West Nile viruses detected in Washtenaw mosquitoes.” lyndontownshipmi.gov/mosquito-borne-illness-jamestown-canyon-and-west-nile-viruses-detected-in-washtenaw-mosquitoes/ (accessed 2026-10-06)
- City of Ann Arbor Forestry, “Oak Trees and Oak Wilt.” www.a2gov.org/forestry/oak-trees-and-oak-wilt/ (accessed 2026-10-06)
- U.S. Department of Housing and Urban Development, “Termite Treatment Exception Areas.” www.hud.gov/sites/dfiles/SFH/documents/SFH_POLI_TERMITE.pdf (accessed 2026-10-06)
- Michigan Department of Agriculture and Rural Development, “Spotted lanternfly confirmed in Berrien County.” www.michigan.gov/invasives/news/2026/09/10/spotted-lanternfly-confirmed-in-berrien-county (accessed 2026-10-06)
- Michigan Invasive Species Program (MDARD), “Box Tree Moth.” www.michigan.gov/invasives/id-report/insects/box-tree-moth (accessed 2026-10-06)
- Michigan Invasive Species Program, “Emerald Ash Borer.” www.michigan.gov/invasives/id-report/insects/emerald-ash-borer (accessed 2026-10-06)
- Michigan Department of Agriculture and Rural Development, “Pesticide Application Businesses.” www.michigan.gov/mdard/licensing/pesticide/pesticide-application-business (accessed 2026-10-06)
- USDA ARS and PRISM, via phzmapi.org, “Plant hardiness zone for ZIP 48104 (2023 USDA map data).” phzmapi.org/48104.json (accessed 2026-10-06)
- National Pesticide Information Center, “State Pesticide Regulatory Agencies.” npic.orst.edu/reg/state_agencies.html (accessed 2026-10-06)