The Plant Disease Clinic: Origins and Evolution

By: R.J. Zeyen, Emeritus Professor and Brett Arenz, PDC Director

When the department formed in 1907 there was no Plant Disease Clinic nor Extension program. Then in 1914 the U.S. Congress passed the Smith-Lever Act that created and funded cooperative agricultural extension services at land-grant universities. The cooperative extension services’ purpose was to inform the public about current research and developments in agriculture, advances in home economics and in public policy.

In 1915 Minnesota’s population was largely rural and farms were mainly subsistence. However, during World War II (1941-1945) many city dwellers planted ‘victory gardens’ to supplement shortages of vegetables and fruits caused by wartime shortages. Victory gardeners soon encountered plant disease and other problems. Then, after WWII (the 1950s) there was a growth spurt in suburbs surrounding Minneapolis and St. Paul. This ‘metro growth’ was accompanied by lawn, garden and landscape plant disease problems.

In 1956, largely as a response to the metro growth, the department opened a summer Plant Disease Clinic (PDC) in Stakman Hall. Roy Wilcoxson, a Ph.D. student, was in charge. He worked under the supervision of Herbert Johnson, the department’s only Extension pathologist. The PDC became an important part of the department’s Extension effort. The telephone number of the PDC was listed in the university directory and in local phone directories.

At first, few calls were actually about plant diseases. Calls were about plant identification problems, insect problems and questions about growing garden and landscape plants. Wilcoxson transferred these calls to the appropriate departments, and if printed experiment station bulletins were available, they were mailed to the callers’ homes. Good records were kept of the number of contacts.

Public Television and the Plant Disease Clinic Outreach

In 1955, Twin Cities Public Television was incorporated as Twin City Area Educational Television. It’s call letters were KTCA. Home and garden programs often featured Herbert Johnson showing specimens from the PDC. Faculty from other departments with expertise in agronomy, horticulture and entomology were also involved. Slowly the public in the Twin Cities metro began to understand the University’s Extension programs and PDC activity increased greatly. For example, in 1965 there were 4,110 PDC contacts.

A 1960’s KTCA educational television broadcast on landscape and garden problems.

A 1960’s KTCA educational television broadcast on landscape and garden problems. Plant Disease Clinic specimens were shown by Dr. Herbert Johnson, Clinic Director (third from the left). Also featured were an entomologist, a horticulturalist and an urban forester.

Early on, the PDC played an important educational and training role for Ph.D. students. All plant pathology Ph.D. students spent two weeks ‘volunteering’ in the PDC each summer. The learning curve for these Ph.D. students was steep and some described the PDC as “taxing and tiring but rewarding.” Over the years several graduate student ‘clinic directors’ and assistants went on to establish or work in other plant disease clinics, while others entered Extension plant pathology or became private consultants.

In the late 1960s, and through the 1970s there were epidemics of southern corn leaf blight, dutch elm disease, and oak wilt disease. These epidemics produced a major strain on PDC resources. Then, in 1973 the department began a Plant Health Technology (PHT) undergraduate program, and PHT students began to assist in the PDC. Experience in the PDC for PHT students was the crown jewel in their program. Our very own Professor Brian Steffenson was a PHT student.

The Mobile Plant Disease Laboratory and the Clinic

In 1973 Department Head, Dr. Francis A. Wood, developed a cooperative program with the National Park Service to examine the role of disease in the ecological and environmental management of parks. A “mobile plant disease laboratory” was purchased and used both in national parks like Death Valley National Park in California, Voyagers National Park in Minnesota and the Indiana Dunes National Lakeshore Campground. The mobile laboratory also was used as a plant disease clinic and driven to field days at various Minnesota Agricultural Experiment Station Research and Outreach Centers around the state of Minnesota and to cities in rural Minnesota. 

A 1973 photo of the Mobile Plant Disease Laboratory staffed by two Ph.D. students Bill Anderson (R) and Douglas Sarojak (L).

A 1973 photo of the Mobile Plant Disease Laboratory staffed by two Ph.D. students Bill Anderson (right) and Douglas Sarojak (left). The vehicle was used as a Plant Disease Clinic and for the National Park Service Project.

The early years of the PDC are documented in a 1983 special issue of the Aurora Sporealis. This enlightening and sometimes amusing history begins on page 85 of this online Aurora Sporealis issue.

The Dial U Era

By 1980 the Ph.D. student ‘volunteer’ system in the PDC had ended, primarily due to potential liability issues. Jill Pokorny, a PHT graduate, took charge of the PDC, supervised by Professor Ward Stienstra. Students working in the PDC were often paid assistants.

In 1983, due to deep funding cuts to Extension, the PDC was almost lost. The PDC and its counterparts on the St. Paul campus in horticulture and entomology were combined into a single call-in operation, named Dial U. Callers’ phone bills were charged for telephone consultations. However, few diseases could be diagnosed with confidence over the phone and the Dial U experiment was terminated. The Plant Disease Clinic re-emerged and was funded by charging for consultations, charging for laboratory services and acquiring funding from various contracts.

The Modern Era

Ms. Sandy Gould directed the PDC from 1992-2005, followed by Ms. Amy Holm from 2005-2007, and Mr. Dimitre Mollov from 2007-2013. In 2014 when Dimitre left to become a virologist with the USDA, Dr. Brett Arenz became the PDC Director with Jennifer Flynn as the assistant diagnostician.

Dr. Arenz’s non-PDC role focusing on teaching, and the combination of clinical work and teaching worked beautifully. PDC specimens are used in classrooms and teaching laboratories. These clinical specimens are also useful in recruiting undergraduate students for clinical work.

The PDC regained a major teaching function as undergraduate and graduate students internship experience courses are available in the PDC. The best time for an internship experience is in the summer when the greatest numbers of diseased plant samples come through. For example, in 2017 there were 2250 samples, and 171 plant species with 428 unique host/pest combinations.

The PDC in winter offers less diversity but is involved in grain mold testing. This involves stored grain samples (corn, wheat, soybean) from farm operations. Sample grains are placed on solid growth media to grow out various aflatoxin-forming fungi and thus quantify how badly infected grain lots are. This information helps farmers modify grain storage protocols to protect stored grain.

Current Plant Disease Clinic Director Brett Arenz examining samples in the PDC

Current Plant Disease Clinic Director Brett Arenz examining samples in the PDC.

In 2002, the Department of Homeland Security established the National Plant Diagnostic Network (NPDN). Our PDC became part of a network of over 170 diagnostic labs in the nation. Within this network our PDC established a national reputation for virus diagnostics. This reputation rests on collaboration with the department’s plant virologist, Professor Benham Lockhart. Lockhart is an internationally recognized plant virologist, and other clinics often submit their samples to the PDC for diagnosis. Additionally, the expertise of other faculty and staff from the Departments of Plant Pathology, Agronomy and Plant Genetics, Soil Water and Climate, and Entomology is tapped for difficult samples. The proximity to extensive University of Minnesota faculty and staff expertise is what allows the PDC to succeed.

Accurate and timely diagnosis of sample specimens is the initial step to successful plant health management efforts. Typically, with a diagnostic report, PDC staff also provide the latest information on recommended management strategies, often in the form of Minnesota Agricultural Experiment Station Bulletins authored by Extension faculty and staff.

The PDC never promotes or endorses any particular company or control product(s); rather they provide unbiased information the public can trust. Clinical diagnoses are valuable to private crop consultants, tree care specialists and city foresters who, in turn, offer plant disease management and consultative services to the public.

The PDC has operated for 62 years under several formats and leadership styles. The common denominator, throughout time, is that the PDC offers public access to the myriad of expertise residing in the department and related departments here at the University of Minnesota. For more information about the Plant Disease Clinic website