Stripe Rust Update 4/14/04

April 14, 2004

Xianming Chen
The Pacific Northwest

Stripe rust is developing on winter wheat and barley in experimental nurseries in Mt Vernon, Washington and Corvallis, Oregon. Stripe rust also was found in commercial winter wheat fields in the Mt Vernon area. In wheat growing areas east of the Cascade Mountains, stripe rust has not been observed. On March 25 and April 13, I checked wheat fields in southeast and south-central Washington and northeastern Oregon and did not find stripe rust. Last year, from mid March, stripe rust was developing on susceptible winter wheat cultivars in these areas. This year, stripe rust will occur later in most wheat growing areas in the eastern Pacific Northwest.

California

Wheat growers are facing another stripe rust year. Stripe rust is severe on susceptible wheat cultivars in experimental plots and developing on susceptible cultivars in commercial fields. ‘Summit’ wheat, one of the major cultivars grown this year in California, became susceptible, indicating race changes. We have received stripe rust samples collected by Dr. Lee Jackson from Summit and other cultivars grown in California for identifying races. Stripe rust also is developing on barley in experimental nurseries.

South-Central States

Stripe rust has been reported on wheat in Texas, Louisiana, Arkansas, and Oklahoma. Many fields in Louisiana and Arkansas have been sprayed with fungicides. In Texas, stripe rust is less severe this year than last year, which provides less rust inoculum for states further north like Oklahoma, Kansas, Nebraska, and South Dakota.