Pockets of active stripe rust in Oregon, Idaho and Washington have researchers recommending farmers check their fields before applying herbicide in the spring.
“The earlier you see stripe rust, it’s cause for concern because it means potentially going into the next year, we might see an early flare-up,” said Mike Flowers, extension cereals specialist with Oregon State University. “We normally don’t get enough to actually see large patches in the fall.”
Xianming Chen, plant research geneticist with USDA Agricultural Research Service in Pullman, Wash., said winter conditions this year are similar to 2010. In 2011, farmers experienced a severe stripe rust outbreak. This year could be different, he said, due to colder temperatures in recent weeks, which should kill some rust.
But widespread snow cover across the region could allow some rust to survive, he said.
Wheat planted early in September is “very likely infected,” Chen said. Stripe rust is a concern for the entire Pacific Northwest, he said.
Chen will check fields in early March to assess how much stripe rust survived.
Due to high rust pressure, Chen recommends growers plant resistant spring wheat cultivars, with resistance ratings of 1 through 3 being the best choice. Cultivars with a resistance rating of 5 to 9 should not be planted, Chen said.
Flowers said most farmers are planting resistant varieties, but some susceptible options, including SY Ovation and ORCF-102, are still present. Some newer varieties, like UI Magic, have some susceptibility.
If farmers see stripe rust in their fields in February, they should add fungicide to their herbicide application, Flowers said.
“We don’t really expect anybody to take any action right now,” he said. “It’s more just be aware of it. As things start to warm up in the spring, scout your fields and treat as necessary.”