Soybean rust still no threat to upper Southeast

Asian soybean rust made its usual mid-August push into soybean production areas in the Delta and moved farther into Georgia, but still poses no imminent threat to the crop in the Carolinas, Virginia and Kentucky.

Three tropical systems all appear to be moving away from the Carolinas, reducing the threat of a rapid spread of diseases spores.

Tropical Storm Claudette moved inland around Pensacola and Navarre Beach, Fla. and moved rapidly to the northwest. Tropical Storm Anna and Hurricane Bill both appear to be no threat to the Southeast.

The most active movement of rust in mid-August has been in Mississippi, where a number of commercial fields have been infected. Still, rust watchers stress that so far these disease levels have been low.

On Thursday, Aug. 13, 2009, soybean rust was detected in a commercial soybean field just west of Stoneville/Leland in Mississippi. The soybeans were at the R7 growth stage and not at risk to the disease. Levels of rust within the field were low. The soybean field had not received an R3/R4 fungicide application.

On Friday, Aug. 14, 2009 soybean rust was detected in commercial soybean fields in Carroll, Grenada, Humphreys, Leflore, Montgomery, Sunflower, Yalobusha, and Yazoo counties in Mississippi. Rust levels were extremely low in all of the fields save for one field in Montgomery County, immediately east of Winona. All soybean fields were beyond R5.7 so they are out of the woods and won’t require treatment.

The nearest rust to the Carolinas and Virginia remains at low levels on kudzu in south Georgia and near Greenville, Ala, roughly 30 miles south of Montgomery. Neither state reports any rapid buildup of the disease, nor significant finds in commercial fields.

South Carolina rust watcher John Mueller says, “The closest rust is still in southwest Georgia. So, spraying specifically for rust is not needed in South Carolina.

We are now in our “normal” rust detection window (Aug. 15 to Sept. 15) for the first rust find in South Carolina. We have had plenty of days the last two weeks conducive to rust spore germination and development. We will be intensifying our monitoring program now and we will see if rust has arrived in South Carolina.”

In North Carolina, rust watcher Steve Koenning says it appears North Carolina is out of danger from rust this season. Speaking at the recent Northeast Ag Expo in Elizabeth City, N.C., Koenning says most of the soybeans are near or past growth stage seven and are at little risk from soybean rust.

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TAGS: Soybeans
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