Soyabean rust fungus was confirmed in north-eastern Arkansas and in southern Georgia, the US Agriculture Department said on its Web site that tracks the yield-cutting plant disease.
With the discoveries during the weekend, rust has been identified in 91 counties in eight states in the US South and Southwest. At this point a year ago, rust was in 49 counties in seven states.
"Although it is late in the season, continued spread northward and eastward may be expected," said the USDA site. Rust was found in Jackson County in northeastern Arkansas, about 65 miles north-west of Memphis, Tennessee, and in Colquitt County, Georgia, about 45 miles north-northeast of Tallahassee, Florida.
According to USDA's Web site, rust was found this year in 25 counties in Texas, 14 in Louisiana, 13 in Florida, 10 in Alabama, 10 in Georgia, seven in Arkansas, six in Mississippi and six in Oklahoma.