Just what central Kansas farmers needed: yet another challenge for the 2012 wheat crop.
"We're starting to see something pretty rare in central Kansas, a disease that causes leaf scorching and a tip dieback on the flag leaf," said Ginny Carr, extension agriculture agent in Barton County.
Kansas State University plant pathologist Erick DeWolf said as an infection, bacterial leaf blight has been around for decades but that the conditions that allow it to move into the wheat leaves are rare.
"It has been showing up in central Kansas following thunderstorms," he said.
The bacteria that causes the blight lives in the grasses in road ditches and waterways, he said. When thunderstorms move through, the high winds pick up road sand which blasts the wheat plants, creating wounds in the leaves that allow the bacteria to enter.
The blight causes a scorched, brown look to the leaves and a dieback of the flag leaf from tip toward stem.
"I've seen it primarily in Reno and McPherson counties," he said. "It is rare enough that there really aren't established data on how to forecast yield loss from an infection. And, of course, this is occurring in the areas that have gotten rain, so we are talking a crop that had above average potential and bumping it back to average or even slightly below average."
The good news, he said, is that as the disease emerges the crop is already well along toward maturity and the worst infections have killed only about 40 to 50% of the flag leaf.
"I'm optimistic that leaves enough to finish maturing the crop," he said.
Of greater concern to overall yields for the 2012 crop are the potential losses to drought in a widening area of central Kansas, he said.
"I'm looking at an area moving south and west of Great Bend where the loss to drought stress is significant and worsening," he said. "This has been one of those disappointing years. Early on it looks like you are going to have just a terrific harvest, then you get hit with everything."