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.