Mysterious yellowing affects 40,000 acres of Eastern Oregon; new problem feared

By MATTHEW WEAVER

Capital Press

The Oregon Department of Agriculture and Oregon State University are investigating the yellowing of upward of 40,000 acres of wheat in Umatilla and Morrow counties.

So far, the cause is a mystery, and researchers do not know if the problems in the two counties are related.

In early November, Umatilla County growers noticed wheat fields turning yellow and dying, OSU Extension soil scientist Don Wysocki said.

Sixteen fields from three to 10 miles northwest of Pendleton were affected, Wysocki said. They are "more or less but not completely contiguous," he said. Not every field in the area was affected.

The area was predominately planted to soft white Clearfield variety ORCF-102, but other varieties were also affected, Wysocki said.

"There's probably more than one thing going on in these particular fields, like in any field," he said.

OSU Morrow County Extension associate professor Larry Lutcher said 30,000 to 40,000 acres of wheat in his county have plants with yellow or purple tips. The discoloration spreads inward and downward on the leaf. In some cases, plants are completely desiccated and will not recover.

The symptoms have been observed in many fields in the county, Lutcher said, but do not appear tied to any particular location.

"Most of the symptoms in Morrow County are unlike anything I have ever seen," Lutcher said.

Lutcher said he doesn't believe the problem will spread to other fields, but he can't be certain.

"This does appear to be a new problem -- a problem that no one seems to have experience with," he said.

Neither Lutcher nor Wysocki were sure if the circumstances in the two counties were connected.

"The big question on everyone's mind right now is, how will the crop look this spring and will replanting be necessary?" Lutcher said.

Oregon Department of Agriculture Special Assistant to the Director Brent Searle said the department was contacted by farmers in early November.

The department sampled and tested the fields, but final results are not yet in.

Preliminary samples showed some root pathogen issues, but Searle said the investigation is still in the information-gathering stage.

The department and university sent surveys to growers asking about field history, planting dates, chemical use and where seed was purchased. OSU also examined nearby fallow land to see if it was similarly impacted.

The information may help identify common factors or patterns, Searle and Wysocki said.

In Umatilla County, the patterns are oriented across the fields, with "shadow effects" suggesting protection in areas behind slopes or fence rows, Wysocki said.

But the patterns of the die-off aren't typical of anything anyone has seen before, Searle said.

"The weather's been really weird this year and there was a tight planting window, and then temperature swings and rains and the grain jumped real fast in growth," he said. "It could be a whole combination, perfect storm kind of thing. We're just trying to sort it all out right now."

Most growers in Umatilla County were replanting their fields, Searle and Wysocki said.

Replanted acres aren't expected to have a problem, Wysocki said, "but we can't rule that out."