Source: NY Times
ALTON, Iowa — It has come on like a tidal wave, washing across the Corn Belt from Minnesota to the Texas panhandle, a disease that few farmers had seen until five years ago.
Known as Goss’s wilt, it has cut some farmers’ corn yields in half, and it is still spreading. This summer it reached Louisiana, farther south than it had ever been identified. Alison Robertson, a plant pathologist at Iowa State University, estimated that about 10 percent of this year’s corn crop would fall to Goss’s.
The disease, named for R. W. Goss, a longtime Nebraska plant pathologist, is caused by a bacterium with the formidable name Clavibacter michiganensis subsp. nebraskensis. When a plant is damaged by hail or other heavy weather, the microbe enters the wound and infects its vascular system, scarring the leaves with brownish-yellow lesions sprinkled with black freckles.
The infection may or may not kill the plant, depending on when it comes, but it almost always curtails yields. And for farmers who have never seen the infection before, it is deeply disconcerting.
“The farmer who called me had found a circle of corn about 50 feet in diameter or so that had strange symptoms, stalks broken over and twisting, discoloration, the whole nine yards,” said Clayton Hollier, a plant pathologist at Louisiana State University. “I hadn’t heard symptoms like that since I learned about Goss’s in college.”
Until 2008, Goss’s wilt had been confined to western Nebraska and a handful of counties in eastern Colorado. But that year it was found in Iowa, Illinois, Indiana and Wisconsin.
To read more please click here.