Stripe Rust Spreading Rapidly Across The Northwest

Washington State University said stripe rust is rapidly spreading in wheat fields across the Pacific Northwest.

Researchers say many winter wheat fields have already been treated with fungicides, but disease pressure remains high.  In Central Ferry, WA, plants were at Feekes 7 to 9, and stripe rust reached 100% incidence and 80% severity on the middle canopy and appeared on top leaves on susceptible varieties.

Similar levels are being reported in Mount Vernon, Walla Walla and Hermiston, OR. 

In the Horse Heaven Hills area in south-central Washington, one untreated field showed up to 60% severity.

When it comes to the Palouse, both Washington and Idaho, wheat plants ranged from Feekes 5 to 7.  Stripe rust was not found in commercial fields but was found on goat grass at the edge of a wheat field in Idaho.  In WSU experimental fields around Pullman, stripe rust reached quite uniform throughout the field.  The fungus produced more spores on the low leaves but reached the top leaves.  The disease has developed fast since the last report a month ago.

Stripe rust was found on barley plants in the experimental fields at various locations and reached 60% severity on susceptible varieties at Central Ferry and Mount Vernon.

Stripe Rust Pressures Expected To Continue

With favorable weather expected to continue, WSU warns pressures will likely increase.  Growers are urged to monitor fields closely and consider timely fungicide applications, especially on susceptible varieties.  Click Here for recommendations from WSU.  School officials note while these recommendations were published in early March, they are still valid for late April.

So far, stripe rust has been reported in Washington, Oregon, California, Texas, Oklahoma, Louisiana, Mississippi, and Tennessee. Contrast to the high pressure of stripe rust in the Pacific Northwest, the stripe rust pressure is relatively low in the southcentral Great Plains and southeastern states.

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