Sunflower Pathology Working Group aims to manage sunflower disease

Courtesy/University of Nebraska Panhandle Research and Extension Center Sunflowers grow in a Extension Center plot last year along Highway 71. The Sunflower Pathology Working Group’s mission is to help educate and ultimately manage sunflower diseases through knowledge and awareness.

SCOTTSBLUFF, Neb. – For the last five years, the outlook has been a bit sunnier for producers of an economically significant, yet oft-ignored field crop. 

There are 2 to 2.5 million acres of sunflowers planted across the Great Plains – the majority in North and South Dakota, with substantially high production also in Minnesota, Kansas, Colorado, and Nebraska, according to a “Panhandle Perspectives” news release from the University of Nebraska Panhandle Research and Extension Center. Producers either grow sunflowers to be consumed as oil (oilseed) or direct human consumption (confectionary), and disease is one of the top three yield-limiting factors.

“Despite the economic importance of sunflower and the substantial impact that diseases have on its production, there have been very few sunflower pathology resources available to assist sunflower growers, sunflower seed companies and agricultural professionals,” the news release explains. “This is true for both Extension, and academic reference material. Thus identifying a disease correctly is likely a significant challenge for anyone in the industry.

“Accurate identification is the first step toward the successful use of IPM (integrated pest management) or any management technique.”

In response to this issue, Robert M. Harveson, Ph.D., professor and Extension Plant Pathologist, along with three other pathologists from California, North Dakota and Iowa, established the Sunflower Pathology Working Group in 2013

“With the mission of helping educate and ultimately manage sunflower diseases by increasing knowledge and awareness of diseases through the production and distribution of both extension and academic research-related literature pertaining to diseases in the sunflower crop. This effort has been funded through the North Central IPM Center Working Group Program, which in turn is provided through grants by the U.S. National Institute of Food and Agriculture.”

SPWG has since expanded to include another pathologist from South Dakota and two from Australia.

Initial objectives included: 1) to identify what information growers needed most and in what media format; 2) develop and disseminate that information; 3) develop academic reference information that would help others develop management strategies; and 4) increase communication among pathologists working on sunflower and work together to synergize our efforts. 

In the last five years, SPWG has produced the first Compendium of Sunflower Diseases and Pests, published by the American Phytopathological Society (APS) Press (an entire book); two book chapters; multiple grant proposals; and research and extension publications.

“Extension-oriented literature consists of materials ranging from disease playing cards to diagnostic cards and guides. The initial set of 20 disease diagnostic cards sold out, and has been reprinted, as well as translated into Chinese and re-released in that country,” according to the release. “In 2018, we have published two more refereed journal articles. An invited review article focusing on the results of the 15-year sunflower surveys by the National Sunflower ssociation has recently been accepted and will be published early next year in the applied plant pathology journal Plant Disease as a feature article.

Plans for next year include additional articles for the APS journals Plant Health Progress and Plant Health Instructor, and an interactive iBook, all focusing on diagnostics and education.”

Through his work with the group, Harveson told the Farmer he believes rust is the most predominant disease affecting sunflowers in this area.

“This is a disease similar to wheat or dry bean rust, but it is specific for sunflowers. The disease on wheat will not go to sunflower and vice versa,” he explained, adding prevention is key for sunflower producers dealing with any type of pathogen. “Proactive management strategies begin with scouting and looking for the presence of the pathogen. Some varieties may be better tolerant, but to my knowledge there are not really ‘resistant’ varieties. One must watch for disease progression and want to protect the newly developing head. Fungicides can be used, but timing of applications is an important fact to consider. Greater damage occurs if the upper leaves closest to the heads are infected at about R5-R6 (reproductive stage). If applied before, the timing is too early and ineffective as is waiting until later after the reproductive stages of 5-6.”

In the future, SPWG plans to continue to produce additional literature on sunflower diseases and become recognized as the authorities on diseases of this crop, Harveson said.

“Prior to the establishment of the Sunflower (Pathology) Working Group in 2013, the most up-to-date monograph on sunflower diseases was published in 1997,” according to the article. “Additionally, a disease compendium focusing on sunflowers did not exist. The compendium series from APS Press is the most important and widely read pathology crop reference guide worldwide.

“Lastly, very few pathology or IPM Extension publications on sunflower diseases were available. SPWG has now fully begun the process of rectifying these limitations. The initial five-year (U.S. Department of Agriculture) grant funding this work has expired, but we have recently re-submitted a new proposal to continue our mission of creating and distributing disease literature for this crop for another five years and beyond.”

Authors of the “Panhandle Perspectives” article referenced in this piece include Harveson; Sam Markell, North Dakota State University; Febina Mathew, South Dakota State University; Charlie Block, Iowa State University; Tom Gulya, USDA (retired); Sue Thompson, University of Southern Queensland, Australia (retired); and Malcom Ryley, University of Southern Queensland, Australia (retired).

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