Cotton plants free of Fusarium wilt have a better
chance of producing high yields than do plants infected with this fungus.
Photo courtesy of National Cotton Council of America.
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Cotton Studies Target Killer: Fusarium Wilt
By Marcia Wood
March 20, 2008 The long, warm days of a typical
California summer make life easy for sun-loving cotton plants. But a fungal
enemy that causes what's known as Fusarium wilt can make things tough for the
plantsand for growers' balance sheets, too.
That's why Agricultural Research Service (ARS) plant pathologist
Rebecca
S. Bennett is researching environmentally friendly ways to fight the
fungus. Bennett works at the
ARS
Western Integrated Cropping Systems Research Unit in Shafter, Calif.
Researchers know the troublesome fungus as Fusarium oxysporum
f.sp. vasinfectum, or FOV race 4. A soil-dweller that was first
detected in California in 2001, FOV race 4 can clog a plants
"plumbing," or vascular system, eventually causing its leaves to
yellow, wilt and die. Yields of the afflicted plant's fluffy white bolls may
plummet.
In a 3-year study, Bennett is looking at solarization, in which soil covered
with plastic tarps might capture enough heat from the sun's rays to kill the
fungus. Though solarization is likely too expensive to use on a widespread
basis on cotton fields, it might be economical for spot-treating highly
infested sites, Bennett said.
Bennett also is collaborating with plant pathologist Tom Gordon of the
University of California-Davis
on an indoor study of the microbe. In that experiment, Fusarium will be
specially equipped with a gene that gives it a bright green glow when viewed
with ultraviolet light in the lab. The telltale glow will make it easier for
Bennett and Gordon to spy on the fungus and, perhaps, to find a way to bring
about its demise.
Related work by other scientists at Shafter and elsewhere focuses on a
different strategy: to breed superior cotton plants that have impressive
natural resistance to the microbe.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.