Priority species are early detection species that are either not found in Oakland County or found in low numbers (bolded), but are likely to cause harm if they become established.
- Asian longhorned beetle (Anoplophora glabripennis)
- Beech Bark Disease (Cryptococcus fagisuga & Neonectria coccinea var. faginta)
- Beech Leaf Disease (Litylenchus crenatae & potential associates)
- Butterbur* (Petasites hybridus)
- Chinese bush clover* (Sericea lespedeza)
- Chinese yam* (Dioscorea oppositifolia)
- Giant hogweed (Heracleum mantegazzianum)
- Himalayan balsam (Impatiens glandulifera)
- Japanese stiltgrass (Microstegium vimineum)
- Kudzu (Pueraria montana var. lobate)
- Lesser celandine* (Ficaria verna)
- Marbled crayfish (Procambarus virginalis)
- Mile a minute weed (Persicaria perfoliata)
- Mountain Pine Beetle (Dendroctonus ponderosae Hopkins)
- New Zealand mud snail (Potamopyrgus antipodarum)
- Parrotfeather milfoil (Myriophyllum aquaticum)
- Porcelainberry* (Ampelopsis glandulosa var. brevipendunculata)
- Red swamp crayfish* (Procambus clarkia)
- Spotted lanternfly* (Lycorma delicatula)
- Water hyacinth (Eichhornia crassipes)
- Water lettuce* (Pistia stratiotes)
- Water primrose (Ludwigia sp.)
- Yellow floating heart* (Nymphoides peltata)