CHICAGO, Ill. – United States soybean farmers will need to stay alert this summer for reports of Asian rust disease and be ready to spray fungicides to contain possible outbreaks, U.S. plant pathologists say.
Their comments followed news from a Brazilian plant pathologist that the disease could cut 2.2 million tonnes from Brazil’s projected 51 million tonne crop. The Brazilian scientist also cautioned that the disease could travel to the U.S. this year for the first time.
While the U.S. plant pathologists discounted fears that the devastating plant disease could be carried on wind currents this spring from Brazil, they said travellers from Brazil could bring the disease back to U.S. fields.
Read Also
Agriculture ministers agree to AgriStability changes
federal government proposed several months ago to increase the compensation rate from 80 to 90 per cent and double the maximum payment from $3 million to $6 million
“This could be the worst disease I’ve ever experienced,” said Glen Hartman, research plant pathologist at the U.S. Department of Agriculture’s National Soybean Research Center, and associate professor at University of Illinois, in Urbana, Ill.
“It is on the bioterrorist list. But there are a lot of unknown factors here, and first of all it’s got to actually get here.”
Asian rust affects soybean plant leaves, parasitizing the soy plant and taking nutrients that normally would go into seed production. Each infection produces numerous microscopic spores that are picked up by wind currents.
The disease, which has been in Asia for at least 100 years, has been noted in Africa, and is now seen in the major South American soy producing countries of Brazil, Uruguay and Argentina, Hartman said.
Soybeans are grown in central and southeastern U.S., and the government last projected American 2003 seedings would total 73.2 million acres. The U.S. crop was worth $12.287 billion US in 2001, according to the USDA.
Hartman said that the rust’s effect would depend on the severity of an outbreak and the time it appears.
“If it’s introduced in late August, losses would probably be minimal because the disease needs a living host, but if it were introduced in the U.S. Midwest in mid-June, it could be a disaster,” he said.
“It would depend on whether we can get all the fungicides applied over a two-week period and protect the crop. And once you get done with the fields, you’re going to have to go back and spray again.
“In a worse case scenario, if it were introduced like that, there could be 20-30 percent loss,” he said. “I’ve seen fields with up to 80 percent loss.”
Greg Shaner, a Purdue University plant pathologist, agreed that the disease was among the worst he had seen.
“There is potential for a wide-scale epidemic,” Shaner said. “It can be transported on the clothing of somebody who has been walking around a soybean field in South America and then comes back here.
