May 25, 2011

Northern New York – Northern New York growers whose alfalfa crops are slow to emerge this spring may need to check fields for brown root rot. The farmer-driven Northern New York Agricultural Development Program has provided funding to continue research into the crop disease that can cause alfalfa and perennial forage crop losses in excess of 60 percent.

Earlier Northern New York Agricultural Development Program-funded research surveyed alfalfa production fields in the Northern New York region and identified a complex of seven biotypes (varieties) of the fungus Phoma sclerotioides that causes brown root rot.

Brown root rot (BRR) was initially discovered in New York State in Clinton County in 2003. One of the seven biotypes has been named P. sclerotioides var. champlainii, indicative of the county’s proximity to Lake Champlain and the fact that BRR has also been found on the Vermont side of the lake.

BRR causes lesions on the tap roots and crowns of alfalfa and other perennial forage legumes. Disease symptoms develop in late winter and early spring. Severely affected plants often fail to emerge from winter dormancy or exhibit delayed spring regrowth.

“State funding of the Northern New York Agricultural Development Program has helped New York agriculture inestimably by providing the means to continue research into brown root rot. Our research in Northern New York farm fields has shown as many as five of the seven biotypes, sometimes five in a single field,” says Gary C. Bergstrom, a Cornell University Professor of Plant Pathology and Plant-Microbe Biology.

Bergstrom co-authored a May 2011 Phytopathology professional journal article - “Genetic and Morphological Evidence that Phoma sclerotioides, Causal Agent of Brown Root Rot of Alfalfa, Is Composed of a Species Complex” - on the biotypes with Michael J. Wunsch. Wunsch says, “The identification of subtypes of the brown root rot pathogen is expected to facilitate growers’ improved management of the disease.”

The Northern New York Agricultural Development Program (NNYADP) has designated 2011 project funding from the Cornell University Agricultural Experiment Station for the selective breeding and field trials of BRR-resistance alfalfa varieties as part of a management strategy to help regional farmers protect the valuable dairy and livestock crop. The Cornell University research team includes plant breeder Dr. Donald R. Viands and Plant Breeding and Genetics Senior Research Associate Julie L. Hansen.

This NNYADP research has the potential to also help growers in other areas of North America. Brown root rot is known to impact alfalfa and other perennial forage crops grown in central, northern and eastern Canada, in areas from the Rocky Mountain states south to New Mexico, in the upper Midwest, and in New England and Pennsylvania.

Wunsch was the primary researcher on the NNYADP-funded brown root rot project in Northern New York as a Cornell University graduate student. He is now a plant pathologist with the Carrington Research Extension Center at North Dakota State University.

“Among other closely-related Phoma pathogens, similar subtypes are associated with differences in virulence, host range, temperature adaptation, and other economically-important characteristics. As we learn more about the biology of each subtype of brown root rot, the knowledge of which subtypes exist in a particular location will allow for the implementation of locally-adapted management strategies,” Wunsch says.

More information on NNY brown root rot research is posted under Grass-based Agriculture on the Northern New York Agricultural Development Program at www.nnyagdev.org. 

The Northern New York Agricultural Development Program (NNYADP) is a farmer-driven research and outreach program specific to Clinton, Essex, Franklin, Jefferson, Lewis and St. Lawrence counties. The Northern New York region has 1.1-plus million acres in agriculture use and produces farm products with a market value of more than $595 million. The NNY farm employee payroll circulates approximately $52.9 million in the regional economy. Learn more at www.nnyagdev.org.  #

Media Contacts:
• Gary C. Bergstrom, Cornell University, 607-255-7849
• Donald R. Viands, Cornell University, 607-255-3081
• Julie L. Hansen, Cornell University, 607-255-5043
• NNYADP Co-Chair Jon Greenwood, 315-386-3231
• NNYADP Co-Chair Joe Giroux, 518-565-4730
• Northern New York Cornell Cooperative Extension
• Clinton County: Peter Hagar, 518-561-7450
• Essex County: Anita Deming, 518-962-4810
• Franklin County: Stephen Canner, 518-483-7403
• Jefferson County: Mike Hunter, 315-788-8450
• Lewis County: Joe Lawrence, 315-376-5270
• St. Lawrence County: Stephen Canner, 315-379-9192
• BRR plant damage jpgs: NNYADP Publicist Kara Lynn Dunn, 315-465-7578