Signs of drought in soybeans
Aug 27, 2009 2:32 PM, By Tobie Blanchard, LSU AgCenter
Louisiana’s soybean harvest is just getting started. A small portion of the crop is out of the fields, and these early-harvested beans revealed lingering effects of the midsummer drought, according to experts with the LSU AgCenter.
Some farmers are seeing low yields, said LSU AgCenter soybean specialist Ron Levy.
“A lot of these beans that were early went through the worst part of the drought,” Levy said. “We’re seeing late-season disease issues in there — quality issues and yield losses.”
Although farmers typically get yields of 30-40 bushels to the acre, some are getting yields in the teens. Levy said farmers are seeing plants that are short and don’t have full canopies.
The disease Asian soybean rust has been found in soybeans in a number of parishes, but LSU AgCenter researchers say there is no reason for alarm.
“We’re finding the rust in only late-maturing beans,” said LSU AgCenter plant pathologist Boyd Padgett. “They’re in the R7 stage, which is close to harvest. They’re beyond needing any protection anyway. They’re trying to finish up and dry down so we can get in the field and harvest them.”
Padgett recommends growers keep an eye on their crop. He said they only need to spray fungicides for the disease if their soybeans are in early stages of maturity with good yield potential and weather conditions are favorable for rust development.
“That would be temperatures in the 60s to upper 70s and about six to 10 hours of leaf wetness” a day, Padgett said.
Growers should watch out for other diseases as well, such as cercospera blight, the LSU AgCenter plant pathologist added.
LSU AgCenter observers said insects have been a problem in some soybean fields, and infestations of late-season insects are increasing but shouldn’t cause much damage at this point.
“We’ve seen some hot spots here and there that had to be treated,” Levy said. “Some of the fields are already getting to the point where farmers are going to be defoliating, so the insects are not going to hurt the yields very much there.”
The LSU AgCenter experts agreed growers will have a better idea of how the crop will yield as more fields are harvested in the coming weeks.
e-mail: tblanchard@agcenter.lsu.edu
