Rust Update 4/29/10

April 29, 2010

Xianming Chen
Stripe rust starts developing in Walla Walla.

Today, I was checking wheat fields in the Connell (Franklin County), Horse Heaven Hills (Benton County), and Walla Walla (Walla Walla County) areas. Stripe rust was not found in the Connell and Horse Heaven Hill areas. One pustule (uredium) of leaf rust was found in an early planted winter wheat field. In Walla Walla, stripe rust was found at a very low level (totally about 10 leaves with single stripes or patches of 1 to 3 cm in length) on the susceptible check. The generally lower than normal temperatures in April have slowed wheat growth and stripe rust development. Winter wheat crop ranged from early jointing (Feekes 4) to boot (Feekes 10) and spring wheat from just planted to late tillering (Feekes 3). Dryland foot rot was found in some early-planted winter wheat fields in the Horse Heaven Hills area.

So far, stripe rust pressure is low in eastern Washington. Our recommendation is not to use fungicides until stripe rust is found in the field. Growers in Walla Walla may start checking fields for stripe rust, especially if susceptible varieties are grown.

Nationally

Wheat stripe rust has been reported in Texas, Louisiana, Arkansas, Oklahoma, Mississippi, Kansas, Virginia, California, Oregon and Washington. Barley stripe rust has been reported in California, (western) Washington, and (western) Oregon.