Chemicals less and less effective against Asian rust in Brazil's soybean fields
Over almost two decades, a plant disease known as Asian rust has infiltrated soybean fields across Brazil -- the world’s biggest exporter of the versatile oilseed used in countless consumer products. But the pathogen has become so resistant to chemicals meant to kill it that many farmers spray several times during their growing seasons, and still endure output losses.
Brazil has become the world’s largest market for fungicides as growers have stepped up the fight against Asian rust and other crop diseases. They spent US$3.2 billion last year, three times what they did a decade earlier. But a state-run research institute found the chemicals were ineffective almost half the time, according to Rabobank, so farmers are spraying more. The pathogens have adapted to become more resistant, confounding growers and scientists.
“Resistance has been faster than research” into preventive measures, said Claudia Godoy, who studies Asian rust on soybeans for Brazilian Agricultural Research Corp., a government-run organization known as Embrapa.