Plant Diagnostic Laboratory

The University of Maryland Plant Diagnostic Laboratory


Established in 1979, the University of Maryland Plant Diagnostic Laboratory (PDL) provides plant problem diagnosis in support of University of Maryland Extension programs in agriculture and horticulture.



Special Notice

The UMD Plant Diagnostic Lab is now open to receive samples shipped to the laboratory from commercial clients.  Due to the university’s COVID-19 restrictions, we cannot accept unscheduled walk-in sample submissions. If you plan to send samples for diagnosis, please let us know by emailing a message to  We encourage clients to email digital images prior to sending physical samples. 

Home gardeners can submit photos and gardening questions to the UMD Home and Garden Information Center website HERE

We will update this announcement if there is a change in this procedure. Thank you for your patience as we deal with this unprecedented situation. 

-Karen Rane, Ph.D., Director, UMD Plant Diagnostic Laboratory


The Plant Diagnostic Laboratory provides plant problem diagnosis for all crops. Most diagnoses are based on microscopic examination of the specimen and visual identification or culture of plant pathogens such as fungi, bacteria and nematodes. Identifications of plants, insects and mites attacking plants are also performed. Some specimens are referred to specialists in other departments or other institutions for diagnosis.

Since 2002, the lab has also been an active member of the National Plant Diagnostic Network, which links together land-grant university plant diagnostic laboratories for the purpose of rapid detection of exotic and invasive plant pest species which pose a threat to US agriculture. Laboratory staff also conduct educational programs on plant pathology topics for various audiences, and prepare fact sheets and other materials related to plant disease management.