MICROSCOPIC WAR: The leaves of this corn plant redden as a result of infection by maize chlorotic dwarf virus, which caused severe crop losses in the midwest and southern United States in the 1960s and ’70s.© BILL BARKSDALE/DESIGN PICS/GETTY IMAGES
In 2011, Noah Phiri was working with local farmers in Kenya to combat the fungal pathogen that causes coffee leaf rust when another virulent plant disease began wiping out maize in the country’s southwest corner. Infected plants developed pale streaks on their leaves, then wilted and died. Some farmers lost as much as 90 percent of their crop that year. Phiri, a plant pathologist at the U.K.-based Centre for Agriculture and Biosciences International (CABI), raced to identify the culprit. He and his colleagues collected samples of sick plants and sent them off to the plant clinic at the Food and Environment Research Agency (now Fera Science) in York, U.K. There, researchers sequenced RNA molecules expressed in the infected corn and identified two viruses that were ...