Plant Pathology and its Presence in Western Nebraska

Robert M. Harveson, Extension Plant Pathologist Panhandle REC, Scottsbluff

Early Studies

Although not officially recognized as a separate entity from botany until about 1920, plant pathology studies were being conducted as early as 1885, prior to the establishment of the Agricultural Experiment Station in 1887.  These studies were promoted by Charles Bessey, the first Dean of the College of Agriculture.  Bessey was initially hired as the first station botanist, and conducted the first work in a small greenhouse on City Campus.  He additionally included plant diseases in his botany course in 1884, although the subject had probably been previously taught by the Horticulture Department as cryptogamic botany - later known as mycology (the study of fungi).  Between 1885 and 1905 almost a dozen reports, papers, and bulletins were produced pertaining to plant diseases by Bessey and his students.

Plant Pathology in Moves to Western Nebraska

Potato production became the first subject of plant disease studies in western Nebraska.  In the summer of 1909 (prior to the establishment of the Scotts Bluff Experimental Substation in 1910) a potato disease lab was set up in Alliance with the help of special legislative funds to study storage diseases of potatoes.  Work on tuber dry rot (caused by Fusarium trichothecioides) by Link served as his M.S. thesis in 1912, and also resulted in the publication of the first Research Bulletin (#1) of the Experiment Station.  Link later published a comparative physiological study of the wilt fungus (caused by Fusarium oxysporum) with the dry-rot fungus in 1916 as Research Bulletin #9 (also his Ph.D. thesis).

During the early 1920’s, both E. Mead Wilcox (Station Plant Pathologist) and Robert W. Goss (later Dean of the Graduate College) attempted to set up plant disease experiments at the Scotts Bluff Substation, but gave up after several years.  The director of the substation at that time (James Holden) had no interest in research collaborations with East Campus staff members.  In the mid-twenties, additional work was begun with the purpose of reversing severe yield reductions in alfalfa crops due to the combination of the bacterial wilt disease and winter injury through the collaborations of UNL plant pathologist George Peltier, USDA, and the Agronomy Department.  This resulted in the variety ‘Ranger’ which became the first winter hardy, wilt resistant variety ever developed.  It subsequently became the leading variety grown in the U.S. through the 1960’s.

In 1930, an experimental farm was established by the Experiment Station near Alliance (later known as the NW Agricultural Lab) in cooperation with Box Butte County with the primary purpose of studying potatoes under dry land conditions. After unsuccessfully working with Holden at the Scotts Bluff Substation, Goss continued at the Alliance field lab working with soilborne diseases such as scab and root rot (Rhizoctonia) and some of the first studies in the U.S. with virus diseases.

Expansion of Plant Pathology in Western Nebraska

The arrival of Lionel Harris resulted in a change of philosophy for collaboration with the University of Nebraska as he promoted maximum cooperation with East Campus staff members and Extension.  Plant pathology has played a major role in both research and extension activities ever since.  For the next 30 years, plant pathology personnel from East Campus were stationed at Scottsbluff during the summers to conduct field experiments and address disease problems more efficiently.  Beginning in 1946, Max Schuster was assigned this task, and studied soilborne and virus diseases of potatoes, bacterial diseases of dry beans, corn stalk rots, and sugar beet root diseases.  Some major accomplishments included finding a new disease of sugar beets caused by a nematode pathogen indigenous to western Nebraska, Nacobbus aberrans, (false root-knot nematode).  He additionally identified new color variants (orange and purple) of the bacterial wilt pathogen that are also unique to the Panhandle. 

Two diseases of wheat also provide examples of collaboration between Lincoln-based faculty and those stationed in Scottsbluff, including western streak mosaic and root and crown rot, both of which we are still dealing with today.  Bill Allington, Bob Staples, and Charlie Fenster worked for many years on the epidemiology of western streak mosaic (now known as wheat streak mosaic), and contributed significantly to formulating control measures for the disease.  Root and crown rot was a devastating disease for many years in western Nebraska, but is now managed by planting wheat at appropriate dates for different regions of the state. These recommendations are still being used today and are based largely on results of almost 20 years of research on this topic done by Charlie Fenster and Mike Boosalis.

First Permanent Extension Plant Pathologist

As a result of a committee established in 1965 to evaluate current and future research and extension needs in western Nebraska, the number one recommended priority for new specialist positions in the Panhandle Area was judged to be a plant pathologist.  Thus Eric Kerr was hired in 1967 as the first full-time extension plant pathologist at the Panhandle REC.  His appointment was changed to 50% extension and 50% research in 1980, as the position still exists to this day.

Kerr established effective nematocidal treatments against sugar beet nematodes, and provided the industry with guidelines for determining the threshold levels of nematode populations needed for economical nematocide treatments.  He also studied nematode diseases of corn and the carry-over effects of nematocidal soil treatments in a corn-dry bean-sugar beet rotation.  He developed a forecasting system with Al Weiss (extension climatologist) for Cercospora leaf spot control in sugar beets (which is still in use today).  Lastly, he collaborated with Lincoln-based faculty in the biological control of Rhizoctonia root rot in sugar beets, and control of white mold, rust, and bacterial diseases of dry beans

Changing of the Guard in Scottsbluff

Kerr retired in March 1998 and his position was filled in 1999 by Robert Harveson, who currently has responsibility for specialty crop diseases with an emphasis on sugar beets, dry beans, and sunflowers.  He has determined that Aphanomyces root rot is a major component of the root disease complex in sugar beets (with rhizomania, Rhizoctonia root rot, and others) and is focusing on integrated methods of management including biological, cultural, chemical, and predictive.  He also is studying the re-appearance of the bacterial wilt disease of dry beans (first investigated by M. Schuster in the 1950’s), and its ability to survive on other crops grown in rotation with dry beans.  This work has uncovered the presence of another pathogen color variant (pink) near Scottsbluff which has never been reported from any other location.  He also identified the early stages of sunflower rust for the first time from naturally-occurring field infections in volunteers and wild species, and demonstrated the implications of this for subsequent disease development in commercial sunflower crops.  His extension program has focused on providing a diagnostic service for producers (>22,000 samples since 2000) that tests both soils and plant specimens for disease identification and incidence.  Much of the successes realized by plant pathology have been due to the longstanding technical support of Clay Carlson, and Kathy Nielsen, who have provided more than 50 combined years of experience and service to the Panhandle REC.

Published: May, 2010