Stripe rust enters 'home stretch'
Updated: Tuesday, August 09, 2011 2:38 PM
By MATTHEW WEAVER
Spring wheat varieties may still be susceptible to the stripe rust that has attacked many Northwest wheat fields this season.
Xianming Chen, USDA Agricultural Research Service plant pathologist and stripe rust expert in Pullman, Wash., said most winter wheat is past the flowering stage, so the stripe rust is dying as a result, he said.
However, spring wheat is still susceptible, he said. Most crops in the Palouse area of Eastern Washington and surrounding regions are not quite in the flowering stage. Most fields have already been sprayed, but Chen advises those farmers who haven't to spray.
If they don't have much infection on highly resistant varieties, they probably don't need to spray, Chen said.
Dryer weather means less new infection, but Chen said it takes two to three weeks for some rust infections to show up.
Mike Flowers, Oregon State University cereal specialist, expects some yield and quality losses due to rust. He estimated that roughly 1 million acres of wheat in Oregon was sprayed.
Flowers recommends spraying as needed. Some farmers applied chemicals for a third and maybe even a fourth time. Chen doesn't expect spring wheat to need more than two applications of fungicide.
Continued good weather to help the grain fill is key, Flowers said. Hot, dry weather would damage the plants.
In general, Flowers said, farmers have done an "excellent" job controlling the rust.
"We're in the home stretch now," he said. "We just want to make sure everything gets finished strong."
Flowers urged farmers to consider next year's varieties and the turnaround time between harvest and planting. He is concerned that the rust and other diseases will "jump" from this year's crop to next year's as farmers plant.
He recommended avoiding planting rust-susceptible varieties like Tubbs 06 early, to reduce the potential for fall stripe rust infection and barley yellowdwarf virus.
"Tubbs 06 is 20 percent of our acreage," Flowers said. "We're not going to replace that in a year. There's just not enough seed available of other varieties."
Farmers in Umatilla, Morrow, Gilliam, Sherman and Wasco counties should also consider insecticidal seed treatments for protection from fall aphids, Flowers said. Aphids showed up in some Eastern Oregon fields last fall.