Reports of stripe rust have been coming in from both the north and south Willamette Valley.
It was found on wheat varieties Goetze, Kaseberg, SY Ovation and Tubbs 06, Mike Flowers, Oregon State University Extension cereals specialist, said.
The disease has not shown up on Kaseberg this early before, Flowers said. The other varieties are “pretty susceptible.”
“We’ve been seeing (stripe rust) pop up in February,” Flowers said. “This is about a month later than what we’ve seen in the last three to four years. I guess that’s a good thing. It’s still early to see it, but it’s a little later than what we’ve seen in the last few years.”
In recent years, stripe rust survived milder winters in the western part of the region to make for early-season infections. This year, colder temperatures lowered the overall foliar disease level in western Oregon, Flowers said.
“We were hopeful that we were going to avoid some of the overwintering,” he said. “It looks like maybe there’s going to be some fields where it did overwinter, but it looks like there’s a lot of fields where it didn’t.”
USDA Agricultural Research Service plant geneticist Xianming Chen in Pullman, Wash., said it’s typical to see stripe rust in western Oregon and western Washington caused by mild winters. He expects to see stripe rust turn up in Mount Vernon, Wash., this spring.
Rust in western Oregon is more likely to spread to eastern Washington than rust from western Washington, Chen said. Stripe rust in western Washington would have to cross taller mountain ranges, while the wind helps move the rust from western Oregon.
“We always get rust, sooner or later,” Chen said.
It’s always better to get ahead of stripe rust, Flowers said. He encourages farmers to scout their fields for hotspots and treat the disease as necessary.
“The key is, once you see it start showing up, you need to get out and treat it,” he said. “You can’t let it blow up into a huge infection.”
Most winter wheat cultivars may not need to be sprayed in Washington, Chen said.
He recommends farmers wait to spray until they see rust. Chen will check fields later in April.
Flowers continues to test fungicide application timing and new products.
A recent check on his research nurseries didn’t show any signs of stripe rust, even highly susceptible varieties.
Pressure from the wheat disease septoria is also low, he said. Flowers has been concerned about fungicide-resistant septoria in the area, and will survey the Willamette Valley to see how prevalent it is.
“We expect both of them will probably get worse, but the more time we buy without having problems, the better off the crop is going to be,” he said.