Soybean rust remains a concern of Arkansas Extension specialists, but a minor one compared to other diseases popping up in the crop.
“Of course, the storms in the Gulf are a concern,” says Scott Monfort, Arkansas Extension plant pathologist. “But until those make landfall and send winds towards us, what can we do?
“Rust is not on the backburner, at all, but it’s only one of a few problems we’re watching. And other things like aerial blight and anthracnose — and frogeye is coming on — are more immediate.”
Don’t make a mistake and wait too long to treat maladies already in the crop. “Growers shouldn’t even consider waiting for rust to show up in hopes they can treat for everything at once. That’s a good way to lose yield.”
Aerial blight, one of the biggest threats to the crops, thrives in the morning conditions lately experienced in much of the state.
“This morning, I was in the Arkansas River Valley and the fog was rolling in off the water,” said Jeremy Ross, Arkansas Extension soybean specialist, in late August. “It hung over those fields until mid-morning. Aerial blight loves that along with the thick canopies and no wind movement.”
And the temperatures are very low for this time of year.
“That is more conducive for disease development, as well. That includes soybean rust, of course, but I’m not really concerned yet. It’s in the state, around Lake Village (for more, see Asian soybean rust in Arkansas) but until it pops up elsewhere, growers should hang on. There’s plenty of scouting for rust going on, so there’s no need to run out and spray a fungicide for rust.
“I’d encourage growers to worry about what is already proven to be problematic this season. A lot our beans will be at R6, or better, in the next couple of weeks. At that point, rust won’t be a concern for yields.”