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Home > Plants, Pests & Pest Control > Pest Management > Invasive Plant Pests > Pathways Survey

Pathways Survey for Early Detection of New and Emerging Pests


What is the Pathways Survey?

The Pathways Survey looks for new and emerging pests in our local agriculture through a combination of pheromone-baited insect trapping and visual inspection. Minnesota Department of Agriculture (MDA) staff visit survey sites biweekly throughout each growing season to monitor for pests and interact with growers about pests of concern. The Pathways Survey was first conducted in 2014 by the Pest Detection and Management Unit of the Plant Protection Division of the MDA, and is currently entering its third season of monitoring. Funding for this multi-pest, early detection survey comes from the U.S. Department of Agriculture (USDA) Farm Bill.

Who is Involved?The 2015 map of the Pathways Survey Sites, photo by MDA.

The survey is conducted at community gardens, community supported agriculture (CSA) farms, and small immigrant farms across Minnesota in both urban and rural areas. Emphasis is placed on population centers, where new pests are likely to be introduced due to the number of pathways by which invasive species can be moved by humans. The metropolitan areas of Minneapolis-St. Paul, Duluth, Rochester, Mankato, and St. Cloud are each represented in the survey. In the 2015 season, a total of 95 sites, including 61 community gardens and 34 farms participated.

How is the Survey Conducted?

The MDA works with the USDA and the University of Minnesota (U of M) to identify insects and pathogens that might pose the greatest risk to Minnesota agriculture. Pests are assessed using criteria such as the following:

  • Likelihood of introduction in the near future
  • Host prevalence within Minnesota’s agricultural crops and natural ecosystem
  • Climactic suitability and cold hardiness

Each year, the list of target species that are monitored for in the Pathways survey is revised as new information becomes available.

Pheromone-baited traps and visual inspections are used to monitor for insect species, insect life stages, and host damage. Plants are also inspected for symptoms of plant diseases, and tissue samples are removed from plants showing symptoms of target pathogens for diagnostic lab testing.

Photo by Angela Stoddard, Minnesota Department of Agriculture (MDA).
Leaf symptoms of Clavibacter michiganensis subspecies michiganensis in tomato, photo by MDA.
Bacterial wilt and
canker of tomato
A brown marmorated stink bug trap. Photo by Angela Stoddard, MDA.
Brown marmorated stink
bug trap
Leaf symptoms of late blight on tomatoes, photo by MDA.
Late blight in tomato

What happens after a detection?

Not all pests pose the same level of threat to Minnesota agriculture; as such, when a pest is found our response varies.

  • Some pests are not regulated. If we find pests that are not regulated, we focus on education and outreach to growers about the pest(s) of concern.
  • Some pests are regulated, either locally or federally. If we find pests that are regulated, a number of things could happen, including:
    • Restrictions on the movement of plants and goods
    • Limitations on exports
    • Efforts to control and/or eradicate the pest(s)

In addition to education, outreach, and potential regulatory consequences upon finding a new pest, the MDA also works to track pests after they have arrived in Minnesota to determine their spread and scope within the state.

2015 Survey Results

In 2015, the Pathways Survey detected bacterial wilt and canker of tomato (Clavibacter michiganensis subsp. michiganensis), late blight of tomato and potato (Phytophthora infestans), and spotted wing drosophila (Drosophila suzukii).

  • Bacterial wilt and canker of tomato (CMM) was found in 16 counties. This pathogen is not regulated in Minnesota but can cause significant loss and further spread could impact commercial growers of tomatoes, peppers, and other solanaceous plants.
  • Late blight of potato and tomato was detected at the end of the season in tomato crops in two counties. This disease can be a concern particularly for potato growers if the pathogen is able to overwinter in potato tubers in the ground or in cull piles. The MDA will continue to monitor for late blight, paying close attention to the seasonal timing and host species of any new detections.
  • Spotted wing drosophila (SWD) was monitored in a separate U of M-affiliated MDA program via a dedicated network of small fruit grower volunteers. The traps set by Pathways inspectors broadened the scope of SWD monitoring and identified SWD activity in three additional counties in community gardens. Learn more about MDA's spotted wing drosophila survey.

Results from previous years will be archived on MDA's website. View results for the 2014 Pathways Survey.

2015 Insect Trapping and Visual Survey

Common Name Scientific Name Survey Method Trap or Visual Check Suspect Samples Collected Positive Confirmations
Golden twin spot moth Chrysodeixis chalcites Trap 404 69 0
Swede midge Contarinia nasturtii Trap 395 267 0
Cucurbit beetle Diabrotica speciosa Visual 500 1 0
Spotted wing drosophila Drosophila suzukii Trap 29 10 7
Fruit-piercing moth Eudocima fullonia Visual 500 0 0
Brown marmorated stink bug Halyomorpha halys Trap, Visual 404, 500 8, 0 0, 0
Wheat bug Nysius huttoni Visual 500 1 0
Large white butterfly Pieris brassicae Visual 500 0 0
Blueberry maggot Rhagoletis mendax Trap 31 0 0
Tomato fruit borer Neoleucinodes elegantalis Trap 401 64 0
Bacterial wilt and canker of tomato Clavibacter michiganensis subsp. michiganensis Visual 500 255 39
Goss's wilt and blight of corn Clavibacter michiganensis subps. nebraskensis Visual 500 37 0
Bacterial wilt of bean Curtobacterium flaccumfaciens Visual 500 48 0
Cucumber green mottle mosaic virus CGMMV Visual 500 68 0
Stem and bulb nematode Ditylenchus dipsaci Visual 500 4 0
Late wilt of corn Harpophora maydis Visual 500 9 0
Java downy mildew of corn Peronosclerospora maydis Visual 500 33 0
Late blight of tomato/potato Phytophthora infestans Visual 500 252 4
Clubroot Plasmodiophora brassicae Visual 500 2 0
Downy mildew of cucurbits Pseudoperonospora cubensis Visual 500 68 0
Bacterial wilt of tomato Ralstonia solanacearum race 1 and race 3 biovar 2 Visual 500 32 0
Brown stripe downy mildew of corn Sclerophthora rayssiae var. zeae Visual 500 35 0

Pathways Survey in 2016

The Pathways Survey has expanded in 2016 to include work in vineyards and berry farms in addition to the vegetable gardens and farms included in previous years. Insects and pathogens being monitored at sites during 2016 include the following:

  • Leek moth (Acrolepiopsis assectella)
  • Golden twin spot moth (Chrysodeixis chalcites)
  • Swede midge (Contarinia nasturtii)
  • Cucurbit beetle (Diabrotica speciosa)
  • Spotted wing Drosophila (Drosophila suzuki)
  • Fruit piercing moth (Eudocima fullonia)
  • European grape berry moth (Eupoecilia ambiguella)
  • Brown marmorated stink bug (Halyomorpha halys)
  • Old world bollworm (Helicoverpa armigera)
  • European grapevine moth (Lobesia botrana)
  • Spotted lanternfly (Lycorma delicatula)
  • Tomato fruit borer (Neoleucinodes elegantalis)
  • Wheat bug (Nysius huttoni)
  • Large white butterfly (Pieris brassicae)
  • Blueberry maggot (Rhagoletis mendax)
  • Bacterial wilt of beans (Curtobacterium flaccumfaciens)
  • Grapevine yellows (Candidatus Phytoplasma australiense)
  • Cucumber green mottle mosaic virus
  • Bacterial wilt and canker of tomato (Clavibacter michiganensis subsp. michiganensis)
  • Clubroot (Plasmodiophora brassicae)
  • Downy mildew of cucurbits (Pseudoperonospora cubensis)
  • Brown stripe downy mildew of corn (Sclerospora rayssiae var. zeae)
  • Java downy mildew of corn (Sclerospora maydis)
  • Goss's wilt (Clavibacter michiganensis subsp. nebraskensis)
  • Late blight (Phytopthphora infestans)
  • Late wilt of corn (Harpophora maydis)
  • Bacterial wilt (Rhalstonia solanacearum Race 3 Biovar 2)
  • Stem and bulb nematode (Ditylenchus dispaci)
  • Pierce's disease (Xyllela fastidiosa)

How To Help

The Pathways survey allows for meaningful interaction between growers, the public, and the MDA in regards to invasive species. It is our hope that the survey will continue to facilitate a partnership with the community to protect our local agriculture systems. Additionally, an early detection of a new pest provides the best opportunity for mitigating its impact on our state.

Last Updated: August 23, 2016