More Asian soybean rust has been found in extreme south-central Louisiana — this time in Iberia and St. Mary parishes. Discovered in R-5 soybeans on Aug. 17, the disease was confirmed on Aug. 18.
The incidence level remains “very, very low,” says David Lanclos, LSU AgCenter soybean specialist. “These latest finds aren’t situations where huge areas are eaten up with rust. Actually, it’s a point of pride that we have people able to find this disease at such early stages.”
With 50 percent-plus already out of the field, the state’s soybean harvest is moving rapidly.
“The more we cut, the more ASR’s potential spread is diminished. Most of the harvested beans have been out of northeast Louisiana. The central part of the state is just beginning to harvest.”
The southwest crop is only now into seed fill and is some seven to eight weeks from harvest. But even the southwest crop isn’t in need of a fungicide “unless ASR is found down there at a higher level. Considering this will be another 105-degree day with little rainfall in sight, we don’t anticipate this disease spreading in a big way.”
Spraying recommendations haven’t changed.
“Take it field-by-field and be conservative with any treatments. When the crop is marginal — as many of our fields are — you have to take everything into account before spraying. Regardless, the vast majority of the crop is far past any need to spray fungicides. If you’ve got extremely late soybeans, consider a tank-mix at R-3.”
For more information, Louisiana producers can also monitor the LSU AgCenter’s rust Web site (http://www.lsuagcenter.com/soybeanrust/) or call the ASR hotline at (800) 516-0865.