Initiative Takes Aim at Fungal Crop Disease
Culprit By Jan
Suszkiw October 2, 2007
The fungus Sclerotinia sclerotiorumwhich affects
sunflower, soybean, canola and dry edible bean cropsforms a hard,
protective casing, called sclerotia, in order to survive unfavorable soil
conditions. This reduces the effectiveness of fungicide treatments, crop
rotation and other measures of control.
But these seemingly impenetrable sclerotia are no match for
Coniothyrium minitrans, a mycoparasite that penetrates the fungus'
casings to feed. A mycoparasite is a parasitic fungus whose host is another
fungus. Now, thanks to the National Sclerotinia Initiative (NSI), a multiorganizational effort
led by the Agricultural Research Service (ARS), C. minitrans could prove a
useful ally to growers in their fight against S. sclerotiorum.
Studies by scientists at North Dakota
State Universityone of many NSI participantsshow that the
mycoparasite can diminish the severity of Sclerotinia infection by destroying
the sclerotia before the fungus germinates.
But no single control is likely to become the "magic bullet" against
S. sclerotiorum, which attacks more than 400 species of plants. That's
why NSI scientists are exploring other strategies as well, notes
Kemp. He administers the initiative as director of the
Red River Valley Agricultural Research Center at Fargo, N.D.
Since 2002, NSI scientists have conducted their research with four
objectives in mind: develop new, disease-resistant varieties; learn more about
S. sclerotiorum's growth and biology; decipher its genomic secrets and
disease epidemiology; and develop new diagnostic tools and disease management
strategies to better protect vulnerable crops.
Sclerotinia outbreaks cost about $242 million annually in yield losses
and diminished quality. Important inroads made to minimize the damage include:
- Risk-assessment maps and indices that farmers can use to take
preventive action in edible dry beans and canola;
- Fungicide evaluations for Sclerotinia head rot control in
- New screening methods that speed the identification and
development of Sclerotinia-resistant varieties.
about the research in the October 2007 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.