Research priorities

The Minnesota Invasive Terrestrial Plants and Pests Center (MITPPC) uses a prioritized funding model to identify terrestrial invasive species that pose the greatest threat to Minnesota. This guides how to direct limited funding resources for research. The goals of our approach are to be fair, transparent, and responsive in our assessment of terrestrial invasive species that threaten Minnesota.

We focus on terrestrial invasive invertebrates (like insects and earthworms), plant pathogens (viruses, bacteria, fungi, phytoplasmas, nematodes, and parasitic plants), and plants that harm valued plants. The top 15 most highly rated in each category are the species we prioritize for future research projects through a regular  request for proposals.

How we rank invasive species

We use a systematic, science-based ranking system to evaluate terrestrial species of concern. The process has 17 criteria that would be most useful to measure the threat an invasive species might pose to Minnesota if left unmanaged.

Each species is rated for each criterion. We then put all the ratings into a computer program that calculates an overall ranking for a species, relative to all other species evaluated. The higher the ranking, the greater the threat a species may pose.

Ranking criteria

Some examples of the criteria used to rank species include:

  • Suitability of Minnesota climate
  • Presence of hosts/habitats in Minnesota
  • Annual reproductive potential
  • Negative impacts to recreation or real estate in Minnesota
  • Negative impacts to ecosystem services

Species evaluations

When we evaluate a species for the potential threat it poses to Minnesota, we make the compiled information available for anyone to access. If new information becomes available or ratings change, we’ll update the evaluation document. We have evaluated over 210 species.

View all MITPPC evaluations

Updates to the rankings

We continually evaluate additional species and refine our process for completeness and accuracy. At least every 2 years, we update our list of rankings. The update reflects new species that have been evaluated and any new information that may affect the ratings of previously evaluated species. We welcome your feedback to inform these updates. 

Comment on an existing evaluation

Submit a new species for evaluation

Detailed description of our process

screenshot of the first page of the prioritization research paper

The following paper provides deeper insight about our prioritization methods and results. It is free to download: 

A participatory method for prioritizing invasive species: Ranking threats to Minnesota's terrestrial ecosystems (Journal of Environmental Management, 2021)

Top-ranked species

The following tabs list the species (or groups of species) of plants, plant pathogens, and invertebrates that our process has currently ranked as top threats.

The lists also include links to the evaluation document for each species that describes the information used in calculating their rank.

Top-ranked plants and evaluations listed alphabetically by scientific name
Scientific name Common name and evaluation link
Amaranthus palmeri Palmer amaranth evaluation
Berberis x ottawensis (B. thunbergii x B. vulgaris) Ottawa barberry evaluation
Bromus inermis; Poa pratensis Smooth brome evaluation; Kentucky bluegrass evaluation
Centaurea stoebe subsp. micranthos; C. diffusa Spotted knapweed evaluationdiffuse knapweed evaluation
Cirsium arvense Canada thistle evaluation
Euphorbia esula Leafy spurge evaluation
Frangula alnus; Rhamnus cathartica Glossy buckthorn evaluation; common buckthorn evaluation
Gypsophila paniculata Baby’s breath evaluation
Lonicera maackii; L. morrowii; L. tatarica; L. japonica Amur honeysuckle evaluation; Morrow's honeysuckle evaluation; Tatarian honeysuckle evaluation; Japanese honeysuckle evaluation
Lupinus polyphyllus Large-leaved lupine evaluation
Microstegium vimineum Japanese stiltgrass evaluation
Phragmites australis subsp. australis European common reed evaluation
Robinia pseudoacacia Black locust evaluation
Tanacetum vulgare Common tansy evaluation
Typha x glauca; T. angustifolia Hybrid cattail evaluation; narrow leaf cattail evaluation
Plant pathogens
Top-ranked plant pathogens and evaluations listed alphabetically by scientific name
Scientific name Common name and evaluation link
Aster yellows phytoplasma

Aster yellows evaluation

Ceratocystis fagacearum Oak wilt evaluation
Cronartium ribicola White pine blister rust evaluation
Geosmithia morbida Thousand cankers disease evaluation
Globodera pallida; G. rostochiensis Pale cyst nematode evaluation; golden cyst nematode evaluation
Heterobasidion irregulare Annosum root rot evaluation
Heterodera latipons, H. filipjevi Cereal cyst nematode (H. latipons) evaluation; cereal cyst nematode (H. filipjevi) evaluation
Hymenoscyphus fraxineus Ash dieback evaluation
Macrophomina phaseolina Charcoal rot evaluation
Ophiostoma novo-ulmi Dutch elm disease evaluation
Phyllachora maydis Corn tar spot evaluation
Phytophthora ramorum Sudden oak death evaluation
Raffaelea quercivora Japanese oak wilt evaluation
Ralstonia solanacearum, Race 3, biovar 2 Potato brown rot evaluation
Tilletia controversa (cereal strain)     Dwarf bunt of wheat evaluation


Invertebrates and insects
Top-ranked invertebrates and insects and evaluations listed alphabetically by scientific name
Scientific name Common name and evaluation link
Agrilus plannipennis; A. biguttatus

Emerald ash borer evaluation; oak splendor beetle evaluation

Anoplophora glabripennis Asian longhorned beetle evaluation
Aphis glycines Soybean aphid evaluation
Dendroctonus ponderosae Mountain pine beetle evaluation
Drosophila suzukii Spotted wing drosophila evaluation
Eupoecilia ambiguella European grape berry moth evaluation
Halyomorpha halys Brown marmorated stink bug evaluation
Helicoverpa armigera Old world bollworm evaluation
Lumbricus rubellus; Amynthas spp. Leaf worm evaluation; jumping worms evaluation
Lymantria dispar dispar; L. dispar asiatica Spongy moth evaluation; L. dispar asiatica evaluation
Popillia japonica Japanese beetle evaluation
Scolytus schevyrewi; S. multistriatus Banded elm bark beetle evaluation; European elm bark beetle evaluation
Sirex noctilio Sirex woodwasp evaluation
Spodoptera littoralis Egyptian cottonworm evaluation
Tetropium fuscum Brown spruce longhorned beetle evaluation