By John Lovett
Agricultural scientists are rethinking their battle plans against plant parasites that cause billions of dollars in annual yield losses for American farmers.
Plant-parasitic nematodes cause an estimated $10 billion in crop losses each year in the United States alone and more than $100 billion globally. Among them is the soybean cyst nematode, responsible for more than $1 billion in annual yield losses in U.S. soybean fields, according to the Crop Protection Network.
Soybean cyst nematodes are microscopic roundworms that live in the soil and infect plant roots. Rather than chewing on roots like insect pests, the nematodes invade root tissue and reprogram a small number of plant cells to serve as feeding sites.
"This plant pest can be absolutely devastating for soybean production, particularly because growers can experience up to 30% yield loss without any visible symptoms above ground," said Asia Kud, an assistant professor of nematology in the Department of Entomology and Plant Pathology for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas Division of Agriculture.
Chemical nematicides, soil treatments and biological controls have had mixed success against the soybean cyst nematode, and many potential solutions carry environmental or economic limitations.
Host resistance—breeding soybean varieties that can withstand infection—has been the most effective and environmentally friendly management tool, but its usefulness is declining, Kud said.
"The same resistance mechanisms have been used over and over for years," Kud said. "Over time, nematodes adapt. Something that worked a decade ago may no longer be effective today, so there's a real need to develop new sources of resistance."
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