Researchers investigate what attacked thousands of acres of wheat in Eastern Oregon last fall—and whether it could happen again.
By Peter Beland
Freak rainstorms fell. Fungi spread. Viruses attacked. Clouds of herbicides drifted. Not necessarily in that order or combination and what exactly happened remains unclear. But what is known is that last fall swaths of wheat on roughly 40,000 acres — worth about $15.4 million — in Umatilla, Morrow and Gilliam counties turned yellow and withered in a perfect storm of bad conditions.
Oregon State University plant pathologist Christopher Mundt got a call in October from OSU Gilliam County extension agent Jordan Maley. “I knew something was wrong when he called; I mean, he’s a fourth-generation farmer,” says Mundt. A crop disease specialist who will excitedly talk about the decades during which he purposefully stressed plants to infect them with all manner of afflictions, Mundt was a bit dumbfounded when Maley described the isolated 150-acre field in Eastern Oregon that had splotches of withered plants. The young wheat leaves were bursting out the sides of the plant instead of sprouting upward, curling up like an accordion. “I saw things I have never seen before,” says Maley. “It’s been very controversial. When it boils down to it, we really don’t know what’s going on.”
The ravaged wheat in Gilliam County was not the only strange thing cropping up in Eastern Oregon wheat fields last fall. According to Maley, September saw two inches of rain in one day in Gilliam County, about 15% of the arid county’s total annual precipitation. Rain fell throughout the region during a time when growers usually can count on weed-free fields to plant the soft white winter wheat for which the Northwest region is known, a crop that has seen a meteoric rise in value worldwide in the past year. With the unusual and early rain, weeds bloomed throughout the region.
In Umatilla County, 16 fields totaling about 5,000 acres were victims of the yellowing. It seems the very thing that killed the weeds in time for planting was the culprit: the herbicide glyphosate. “[It’s] fitting what we’re seeing in the field,” says OSU extension soil scientist Don Wysocki cautiously. “But it’s not what we’re seeing in the labs.”
Other researchers disagree. “I’d say nine-to-one that it’s glyphosate,” says Portland-based Pacific Agriculture Laboratory director Steve Thun. A bet, not an absolute. This discrepancy in conclusions is because samples sent to the Oregon Department of Agriculture and samples sent by growers to private labs such as Pacific Agriculture were tested with two different methodologies. “I’m not sure why two different methods were used,” says Wysocki. The ODA repeatedly said that it would reconcile the two methodologies throughout January and February, but as of mid-March said it had no conclusion. “The ODA is dragging its heels,” says Thun.
While the glyphosate sprayers were in the fields killing rain-born weeds, a weather inversion occurred; the herbicide was pushed down by barometric pressure, sulking in a cloud-like formation to nearby fields of newly planted wheat. It is likely the young plants were stressed by the herbicide contamination, according to Mundt.
Oregon Wheat commissioner Tom McCoy said he heard talk that the pressure to plant in light of the unusual rain put pressure on the herbicide applicators to spray in conditions in which they would normally not spray. “It’s not anybody’s fault,” says Thun, referring to the unusual weather’s effect on the herbicide distribution. The ODA is investigating whether any of the 51 commercial pesticide applicators who sprayed did so in dangerous conditions, but like with the final ruling on what caused the yellowing in the wheat, was not ready in mid-March to release its findings. “If there was a misapplication, we would proceed with enforcement action,” says ODA spokesperson Bruce Pokarney.
Under fire by environmentalists because of fears that it will spur herbicide-resistant weeds, the broad-spectrum herbicide glyphosate has been used in the region for decades. Instead of tilling a fallow field for weeds with a tractor before planting, potentially losing topsoil that is precious in dry-land areas, a grower can apply the herbicide instead. In the past four to five years, versions of this no-till system have been used more and more in light of glyphosate’s dropping price, along with rising fuel costs.
But with its increased use comes the increased likelihood that it could cause unforeseen problems like in Umatilla County. “Chemical companies are really defensive about this,” says Maley. The situation was made worse because it was coupled with cold, wet conditions and a ready supply of rooted dead weeds that triggered widespread fungus growth. “It’s really difficult to place cause and effect,” says Mundt, referring to whether the herbicide weakened the plants and made them susceptible to fungus damage, or the other way around.
In Morrow County, about one in 10 plants were affected on over 30,000 acres of wheat, roughly worth $14 million. Morrow County extension agent Larry Lutcher sent a sample of the yellowed wheat to agriculture labs at Purdue University. They came back positive for three types of serial yellow dwarf virus, a pathogen carried by aphids that can cause widespread damage depending on the amount of aphids carrying it. When Morrow County’s corn farmers harvested, it unleashed swarms of aphids that bred on the wet corn leaves.
In Gilliam County, swarms were so thick in early September that Maley had to wear a facemask when he went for his daily runs. Growers in the Midwest see this a lot more than growers here, says Lutcher. “The symptomology is leaning to aphids,” he says. “But we’re going to have to wait and see.” According to Mundt, farmers will know the severity of the serial yellow dwarf virus this month and later in the season as the virus matures, discoloring and stunting the growth of the wheat.
Herbicides, fungi, viruses and more. No one is ready to make an authoritative diagnosis. “Releasing information prematurely is going to create a lot of speculation,” says OSU weed specialist Dan Ball. Investigators would not release preliminary data to Oregon Business, saying they were afraid of having to do damage control if their speculation was wrong. One thing everyone is willing to speak to is whether this will happen again. The short answer seems to be yes. “We’re talking about multiple causes,” says Ball. “Farming is an inherently risky business… One thing is that it will make people more aware of conditions when they make herbicide applications.”
Growers face new challenges every day. In the past eight years, new strains of aggressive stripe rust, a type of fungus that thrives in wetter conditions, have hit Oregon wheat growers hard. This raises the question of whether the freak rain was indeed an outlier or rather a sign of things to come.
“One of the things climate models are showing is the increasing variability of climate,” says Mundt, stressing that it doesn’t necessarily mean more rain, just more unpredictability.
“It was a perfect storm issue, but we need to keep a closer eye in the future to see what’s happening,” Maley says, noting that what happened last fall was good practice for the future. “We have to stay on top of this, not just from an economic but social standpoint. The world relies on wheat; it’s a staple of diet. We have to make sure.”
OSU recently received a $4 million grant to study how farming will affect and is affected by climate change. According to OSU’s Columbia Basin Agricultural Research Center superintendant Steven Petrie, who is working on the study, increased CO2 levels likely also could increase future wheat yields for Oregon’s $354 million wheat industry. Petrie is confident that this past fall was a fluke. “I’ve been out here for 30 years and I’m constantly impressed [by growers],” he says. “They’re always looking years ahead.”
But the case of the malformed wheat remains unsolved in Gilliam County. When Maley visited the infected field in late September, he looked for the aphids that had swarmed him during his runs, possible carriers of a virus. Despite a thorough search of the disfigured leaves, he found nothing.
“We may not come up with an answer because of all the climatic and management factors,” the veteran ag man says. “Hopefully it will never repeat itself.”