An Asian soybean rust scout team has found the disease in four more Mississippi counties: Calhoun, Coahoma, Quitman and Tallahatchie. All finds were at low levels in mature commercial fields at R7/R8.

Tom Allen, assistant Extension/research professor at the Delta Research and Extension Center in Stoneville, MS, reached Sunday night shortly after he’d found rust in Coahoma County, said fungicide recommendations for the state have not changed. 

“We were out yesterday checking in Calhoun County and found rust,” said Allen. “Today, we found it in Coahoma County. I must have checked 15 or 16 fields in Coahoma County over the last week and finally found rust today.”

Was it in one of the fields already checked or a new one?

“It was in a field I hadn’t checked yet. I’ll recheck some of the fields I’ve already scouted in the next week, or so,” he says.

The latest finds indicate the rust appears to be moving north. While that may be happening, Allen believes the latest rust finds “have been in the fields a little while and are just now showing themselves. The reason for that is, when scouting, we’re looking for red-brown or tan pustules. The red-brown pustules normally mean they’ve been on the plant a bit longer. Most everything we’ve found has been red-browns – most of the spores have been pushed out. Tan pustules are fairly fresh and have more spores.

“Everything we’ve found this weekend was at very low levels – no threat to yields. All finds were at less than 2% incidence, save for the field in Tallahatchie County. There, the field was being desiccated as I drove out.”

Any change on fungicide recommendations?

“No. Everything is the same. At this point, the only thing that’s changed is the number of counties in the ‘confirmed’ column,” he says.