In the field of every soybean farmer, there lurks a potential curse. White mold, caused by the Sclerotinia sclerotiorum fungus, can hide in small masses called sclerotia under the soil. In wet, cool and shady conditions, the dormant fungi spring to life, sending out tendrils that launch spores skyward and onto the flowers of soybean plants. In a matter of weeks, the infection works its way inside the plant, leaving a white-furred husk in its place.
Sclerotinia stem rot plagues farmers across the Midwest every year, causing more than $1.6 billion in losses in the past five years alone, says Damon Smith, an associate professor of plant pathology at the University of Wisconsin-Madison. Protecting against the fungus is tricky, he says, as farmers must apply a fungicide at exactly the…
