Tucked away on the first floor of Stakman Hall, the Plant Disease Clinic (PDC) may not be one of the most famous sites on campus, but it is certainly a valuable one. The PDC is a lifeline to the broader plant-growing community of Minnesota, providing diagnostic services to everyone from homeowners, arborists, crop consultants, farmers, government agencies and other professionals.
In its current iteration, there are three PDC staff members. The PDC Director is Brett Arenz, whose University role combines PDC work with teaching both undergraduate and graduate students. Jennifer Flynn, Diagnostician, is the only full-time PDC employee in the lab, and her role is complemented and supported by Grace Anderson, Assistant Diagnostician.
Plant Disease Clinics: Committed to Health and Help
The University of Minnesota Plant Disease Clinic was founded in 1956 in response to the plant-health needs of Minnesota’s communities. Arenz explains, “From what I could tell, individual faculty members were getting overwhelmed by the public calling them up and trying to get answers to their individual plant needs, whether they were farmers, homeowners, or anything else. Basically, they wanted a central resource where people could send samples and take a load off the professors.” The Plant Disease Clinic has been through many eras, including the addition of a “Mobile Plant Disease Clinic” in the mid-1970s, which traveled the state answering plant-disease-related questions, per Aurora Sporealis articles at the time.
UMN’s PDC is part of the broader National Plant Disease Network (NPDN), which was founded in 2002 and connects plant disease clinics nationwide. Most clinics in the NPDN are part of land grant universities, but there are also state departments of agriculture and private labs who participate. Some clinics are part of their university’s extension department, and that or other integrations provide for majority or total funding. Our PDC is not part of Extension, leading it to charge fees around $50 per sample, but the Department of Plant Pathology provides accounting services, workspace, partial staffing, utilities, and other resources.
Being integrated into the University also allows for regular use of the consultation and expertise that fellow UMN faculty and staff are able to provide. “We consult with so many people in our department and other departments,” Arenz says. “If I find something that’s a little confusing on corn or soybean, I’ll bring it to Dean, or a weird looking tree disease, I’ll bring to Bob. . . If you think of all the knowledge and expertise here at the U, the clinic is a kind of filter and lens for the general public to get access to it.”
NPDN membership provides a variety of networking, knowledge-sharing, and continuing education opportunities. The NPDN’s National Data Repository database, in which clinics record hosts and diseases found in their labs to be part of a nationwide communal resource, is both used and contributed to by the UMN-PDC. This results in funding, as does Jennifer Flynn’s role in the NPDN’s Regulatory Relations Committee. Arenz has also participated in the professional development program, which provides diagnostics insights and expertise. Arenz points out that this resource is especially valuable to labs with newer staff and/or no institutional memory, such as after the departure of a prominent leader.
The NPDN also has regional groups, and the UMN-PDC belongs to the North Central Plant Diagnostic Network (NCPDN). Interactions with that group are even more regular, with a monthly call providing a regular forum for members to problem-solve, share information, and discuss patterns they are seeing.
Many Plants, Many Purposes
Per Arenz, the Plant Disease Clinic gets around 2000 samples per year, from a wide variety of clientele and a breadth of plants as well (150 species or more per year). As a Minnesota-based clinic, many of the samples are corn and soybean, as well as tree samples such as oak, pine, and spruce.
Anderson emphasizes the importance of client relationships and the “exchange of information over the years” that benefits both clinic and client. She cites arborists with helping give a better picture of “how the trees are reacting to, say, the drought,” which informs her clinic work, and that “the entire floriculture nursery community bring their plants to us,” leading to more close relationships and spotting of patterns.
Plant diagnoses serve a variety of practical purposes:
- Disease Management: Growers who are unsure of what a disease is, or how to manage it, can find valuable strategies for next year through getting a diagnosis. This can include picking a different variety, crop rotation, changing fungicide or herbicide use, or other strategies.
- Crop Insurance: Growers who need documentation of disease to receive crop insurance money, regardless of whether or not they themselves know the diagnosis, can receive confirmation from the PDC.
- Preserving Treasures and Heirlooms: Homeowners and gardeners with a prized tree or plant, often with familial or sentimental value, use diagnoses to better accept and understand what needs to be done.
- Unbiased Diagnoses: Tree care customers can use a PDC diagnosis as evidence that an expensive solution proposed by a vendor is actually worthwhile.
- Government Agency Research: Several government agencies use the PDC when they require diagnostic testing done locally in Minnesota.
- Commercial nurseries: Popular Twin Cities garden centers use the PDC for healthy propagation processes by diagnosing “problem” plants to see if illnesses will be spread through propagation.
- UMN Researchers: The PDC regularly receives samples from UMN researchers who have field or greenhouse trials with unanticipated pest/pathogen issues that could threaten the accuracy of their studies.
Some plants make better PDC samples than others. To use oak wilt as an example:
- Is it worth the cost of submitting a sample? Mature oak trees are high-value plants that can enhance the property value of a home by tens of thousands of dollars, leading them to be worth preserving year over year. With many inexpensive garden annuals, it is often more cost-efficient just to buy a new plant.
- Is it easy to diagnose without the help of the Clinic? Oak wilt has many look-alike conditions, and even arborists can confuse oak wilt with similar-looking issues like two-lined chestnut borer. Some diseases that are highly prevalent are rarely samples at the PDC because they are so easy to diagnose at home, such as powdery mildew.
- Is there actually something to do about the disease? Taking an infected oak tree down can cost thousands of dollars, but is important to protecting the health of other oaks on the property. Customers want to ensure that, if they are taking an oak down, it is worth the cost and loss.
Diagnostics: A Skill for Life
Students can take an internship clinic as a class—PLPA 8090—for credits that coordinate to the amount of time spent in the lab. Arenz recommends taking it in the summer to see the greatest variety of species and pathogens. The experience centers on hands-on learning, with the student diagnosing real-life samples using the lab’s resources before consulting with PDC staff to discuss correct diagnosis and process. Regardless of whether a Plant Pathology student wants to be a plant diagnostician, the PDC is an excellent space for building all-purpose skills and becoming a well-rounded scientist.
While working with a PLPA phytobacteriology lab recently, Anderson recalls sensing “impatience amongst the grad students with basic classic technique when there are so many fast molecular things you can do now. A good basis in a lab doing classic plant pathology, classic biology, is really important because you aren’t always going to be handed a sample and know what it is. You may have to figure it out from ground level.”
Arenz adds, “A lot of molecular processes are not really that speedy and if you have ten different plants that come in one day during the summer, you won’t have time to do DNA extraction and different molecular tests on all of them. Neither would it be cost efficient. So it’s about trying to deal with the sample in the most efficient way possible; most of the time that does not involve molecular work. Molecular work is really a last resort for when you can’t diagnose it any other way—maybe it’s a virus, or a bacteria that is inside a cell or phytoplasma.”
Variety is a Constant
During his time at the PDC, Arenz says, “I've enjoyed diagnostics. You’re learning new things every single day. It’s sort of like Christmas—you get presents that come in the mail or are delivered to the doorstep and you have no idea what they’re going to be until you open them. Maybe 20% of the time people will call up and tell us they’re going to submit something but usually things just show up, especially in the height of the summer. You don’t really know what the day is going to be like just showing up on the door.”
Anderson agrees, saying, “It’s not boring, which is perfect for me.” She adds, “You can never presume you know what [the client is] talking about. I’ve had people totally end up in a different place once you get down to it. We listen to someone talking about saving a tree and how it’s so precious and their grandmother planted it and you get a picture via email and it is DEAD. We’re talking about something with no leaves and nothing going on there. You never know.”
At the intersection of the plant-loving public and plant pathology research is the PDC. “I think there are people who don’t even know we exist; I think we’re one of those secret powerful jewels,” says Anderson. “It’s not for everybody but I do think it’s very important that people know about us and our connections throughout the country. It’s bigger than just a little lab on the Saint Paul campus.”