April 14, 2008
Contact: Gary C. Bergstrom, Cornell University, 607-255-7849, Michael Wunsch, cell: 607-351-4234; or NNY Cornell Cooperative Extension offices

Note: Michael Wunsch will be checking alfalfa variety plots and sampling forage grass fields in NNY sometime late April to mid-May, depending on weather and field availability � call Michael at 607-351-4234 or Kara Dunn at 315-465-7578 to schedule field interviews.

Cornell Researchers Urge Farmers to Look Now for Brown Root Rot: Photo Resource Online at www.nnyagdev.org

Now is the time to scout fields for brown root rot say Cornell University researchers. With a grant from the Northern New York Agricultural Development Program, a team of Cornell faculty and Extension educators are helping regional farmers recognize the disease in alfalfa and forage grass crops.

Cornell Plant Pathology Professor Gary C. Bergstrom says, �April through early May is the best time to assess over-wintered alfalfa plants for the symptoms of brown root rot.�

Brown root rot, caused by the fungus Phoma sclerotiodes, is a cold-weather disease affecting the roots and crowns of alfalfa during the dormant period when plants are not actively growing. To help farmers recognized brown root rot damage, an online resource in the Field Crops: Alfalfa section at www.nnyagdev.org (or click here) includes photographs of the disease confirmed in Northern New York in 2003.

Bergstrom says, �Characteristic lesions can be seen on the roots and crown of plants showing slow regrowth of shoots from the crown buds in spring.�

To assess crops farmer need only a shovel or trowel, a bucket of water and a pocket knife for digging up, cleaning and slicing the roots of the alfalfa to determine if the plant has lesions and how deep they run. The lesions are usually light to dark brown with a darker edge. The severity of brown root rot increases as plants age and experience more winters. Absolute confirmation of the disease requires a molecular laboratory test that is now available from the Cornell University Plant Disease Diagnostic Clinic. A composite field sample costs $40.

Clinton County in Northern New York was the first county in the state to be confirmed to have brown root rot in 2003. High incidence levels of the disease have since been seen in alfalfa fields across NNY and in Western New York and the Southern Tier of the estate.

Cornell Plant Pathology graduate student Michael Wunsch says, �Spatial patterns within the tested fields (8 of 10 fields in NY, 6 of 7 fields in Vermont, and 5 of 6 fields in New Hampshire tested positive for BRR) suggest the pathogen was not recently introduced in the Northeast.�

Brown root rot has been in Western Canada and Northwestern U.S. crops for decades. It was first observed in the lower 48 states in Wyoming in 1996. In eastern North America, prior to the recent Cornell field surveys in New York, it had been reported in only Nova Scotia.

With funding from the Northern New York Agricultural Development Program, Bergstrom and a research team from Cornell that includes Wunsch, Everett Thomas at the William H. Miner Agricultural Research Institute, Michael Davis at the Cornell E. V. Baker Agricultural Research Farm, and Brett and Jay and Lew Dickson of Dickson and Sons, Inc., Bath, NY, are conducting alfalfa variety trials in regional soils infested with brown root rot in order to identify varieties that may be more disease-resistant.

Fields with 11 varieties of alfalfa at the W. H. Miner Agricultural Research Institute in Chazy, NY, and at the Cornell E.V. Baker Agricultural Research Farm in Willsboro were inoculated with Phoma sclerotiodes in spring 2006 and spring 2007. This spring 125 plants of each of the varieties will be collected and assessed for brown root rot at Cornell laboratories. Six species of forage grasses planted at both farms will be similarly evaluated. A field survey of forage production fields is also underway in each of the six NNY counties: Jefferson, Lewis, St. Lawrence, Franklin, Clinton and Essex.

Farmers from across the region lead the Northern New York Agricultural Development Program which funds regional on-farm research, education and outreach for the agricultural industry. To learn more, go online to www.nnyagdev.org. Farmers can contact their local Cornell Cooperative Extension office for more information on brown root rot. # # #