Two more cases of Asian soybean rust have been found on Georgia's coastal plain. The state's Brooks and Effingham counties are the latest place of residence for the soybean disease.
“Finding rust in Brooks County isn't a big surprise — it's right on the Florida border, south of Colquitt County,” said Bob Kemerait, Georgia Extension plant pathologist July 29. “There's now a line of Georgia counties with rust — Colquitt, Brooks and Tift.”
The Brooks County sample was collected on a private research farm. “One of the employees saw a suspicious leaf and brought it in. We check many suspicious samples that aren't rust. But this one was the real deal. There are some sharp people working on that farm.”
While not downplaying the Brooks County discovery, Kemerait described the Effingham County sentinel plot sample as “much more significant and disturbing.” The reason: Effingham County is just north of Savannah on the South Carolina border — well away from other areas where rust has been confirmed. We didn't expect to find it. Unfortunately, at least a couple of the leaves collected July 28 by Extension agent Bill Tyson are definitely positive for rust.
“We now have rust sites in a broken line from the Alabama border in the southwest corner of Georgia's coastal plain all the way up to the northeast corner of the plain. It's a light sprinkling, nothing major. But we have to assume it could be anywhere in the southern part of the state.”
Fungicide recommendations continue to be “any coastal plain producer with a crop in the R-1 stage or beyond needs to seriously consider spraying.”
Kemerait attended a producer meeting before the discovery in Effingham County. “I told the growers, ‘We don't think rust is here yet. To be safe, you can spray. But if you don't, there's probably time to hold off and see if rust moves in.’
“After this finding, of course, Extension went back and told the growers, ‘We've got it.’ We're emphasizing the need to spray on the coastal plain.”
Kemerait said the disease has yet to “blow up. Anyone spraying probably doesn't need to go with their biggest gun first. In most cases, a protective fungicide will do the job.”