Rust Update 4/30/08

April 30, 2008

Xianming Chen

I was checking fields in Central Ferry, Walla Walla, Horse Heaven Hills, and Connell areas yesterday. Stripe rust has become easy to find in the Horse Heaven Hills area. Some early planted fields grown with Buchanan and Finley had stripe rust severities up to 10% incidence and 5% severity. Many such fields have been sprayed with fungicides. Stripe rust just started showing up in the Walla Walla area. Actually, I was able to find only one infection in susceptible spreader (PS 279) rows in our stripe rust nursery and did not find rust in commercial fields. Stripe rust was not found in Central Ferry and Connell areas. In general, stripe rust has been developing slowly in eastern Washington.

In the Mount Vernon area in western Washington, stripe rust had developed up to 100% severity on highly susceptible entries by April 24 when we were taking the disease notes for winter crop nurseries and planting spring crop nurseries.

Leaf rust was found on about 3-4 low leaves in a small spot in a field in Horse Heaven Hills yesterday.

Powdery mildew was found at the similar level (about 10% on low leaves) in the same fields (one in Horse Heaven Hills and one near Connell) as reported in April 9.