The spread of soybean rust may be increasing in the south-eastern United States after the US Agriculture Department said on Thursday possible rust spores were likely discovered in Tennessee and Kentucky. The USDA said it found what is believed to be soybean rust spores on traps in Warren County, Kentucky, and Madison County, Tennessee. But USDA expressed caution over the findings.
"Other spore traps in each state were negative for spores and no soybean rust has been found on soybean or kudzu in either state," USDA said on its soybean rust web site. "Finding spores simply means that soybean rust may soon be found here."
Given the low level of spores, USDA said, it will "be some time before infections will be visible, let alone be of any consequence" to growers.
The highly contagious soybean rust so far has been found on soybean plants in three states this year - Alabama, Florida and Georgia. Researchers are keeping close watch on what impact Tropical Storm Cindy and Hurricane Dennis had in spreading the disease throughout the south-east.
Monitoring for soybean rust will be closely watched between seven and 10 days after Hurricane Dennis, which is forecast to reach the United States this weekend.
The soybean fungus erupts in reddish-brown lesions on soy plants, causing them to drop their leaves and slashing production by as much as 80 percent. Rust spores are destroyed when exposed to direct sunlight. They can travel up to 100 miles a day in the right conditions.