Stripe Rust Update 3/12/04

March 12, 2004

Xianming Chen

In northwestern Washington, winter wheat crops are in late tillering to early jointing stage. Stripe rust is developing in our rust nurseries in Mt. Vernon and commercial fields in Skagit County. On March 11, 100% plants of susceptible entries in the experimental nurseries had stripe rust with severity levels up to 30%. Several commercial fields had severe stripe rust, up to 50% of incidence and 30% of severity. Stripe rust uniformly distributed in commercial fields. Lower leaves had more rust than upper leaves. Stripe rust severities and distribution patterns are typical for that region at this time of year.

Stripe rust has been reported in Texas, Louisiana, and California. Early this month, stripe rust was lighter than this time of the last year in Texas and Louisiana. In California, up to 30% stripe rust was reported on susceptible varieties in experimental nurseries in the Sacramento/San Joaquin Delta area.