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Plant Pathology

The Plant Pathology Laboratory (PPL) is responsible for identifying plant diseases and pests regulated by the Michigan Department of Agriculture and Rural Development. PPL also collaborates with the Michigan State University Plant Diagnostic Lab, U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), Michigan Department of Natural Resources, and other researchers to develop unified responses to new invasive plant diseases.

The Plant Pathology Laboratory provides three primary services: diagnostics, export certification, and surveys.


The PPL participates in the National Plant Diagnostic Network (NPDN), working with over 70 diagnostic labs across the nation to detect, identify, and respond to new plant pests and pathogens which could impacting U.S. agriculture and the environment. MDARD’s PPL can test for all types of plant disease organisms (bacteria, fungi, phytoplasmas, and viruses) using a range of techniques, including microscopy, culture/isolation, serological tests, and molecular tests. The PPL also collaborates with the Michigan State University’s Plant Diagnostic Lab to homeowners and farmers with diagnosing disease problems.


Clean Plant Certification

Michigan is an active participant in the National Clean Plant Network (NCPN), an organization dedicated to safeguarding specialty crops by providing a sustainable source of clean plants. When plants are produced from a relatively small number of stock plants, it is important the stock plants are as healthy or “clean” as possible. Specialized virus certification programs are available in Michigan for blueberries, raspberries and/or blackberries to ensure clean stock is uses. Stock plants carrying a virus are not always easily identified but can cause harm if allowed to propagate.

Export certification

When plants are shipped from Michigan to a different state or country, the destination location may require an inspection and certification to ensure they are free of plant pests. If an inspection is completed, plants will receive a health certificate, state phytosanitary certificate, or an export certificate.


Plant pathology survey work is closely linked to the USDA’s Cooperative Agricultural Pest Survey (CAPS) Program, which identifies national, regional, and state plant pests of concern and provides program support to survey for those pests. In Michigan, pests of current survey interest include Phytophthora ramorum  (sudden oak death), Potato cyst nematode (PCN), and  Xylella fastidiosa.

Quick Links

Buggin' Out: Plant viruses can significantly impact our crops and food production, but are they also a threat to our health? We spoke with a plant pathologist to help us understand how to detect plant viruses. (video)

Invasives Watch List: Invasive species on the watch list have been identified as posing an immediate or potential threat to Michigan's economy, environment or human health.