2007 Rust Summary

July 13, 2007

Xianming Chen

Due to the hot and dry weather conditions in the first two weeks of July, the stripe rust season in most part of the Pacific Northwest is almost over. Similar to 2006, stripe rust of wheat has been light in commercial fields and therefore, yield losses caused by stripe rust should be low. However, stripe rust has developed to 100% severity on susceptible entries in non-irrigated experimental plots of both winter and spring wheat under natural infection in Washington, and 60-80% severities in wheat nurseries in northeastern Oregon and northern Idaho.

Nationwide, stripe rust of wheat has been reported in Texas, Louisiana, Alabama, Arkansas, Kansas, Colorado, Nebraska, Virginia, California, Washington, Oregon, Idaho, Montana, and South Dakota. Similar to 2006, stripe rust severity has been generally low, except for some regions in Texas under irrigation and in Kansas and Colorado.

Stripe rust of barley has been reported in California, Colorado, and Washington, and has been generally at very low levels of severity.

In the Pacific Northwest, wheat leaf rust has been found at a low level in northwestern Washington and in fields under irrigation in central Washington, and is basically absent in commercial fields. Barley leaf rust was severe on winter barley in nurseries in northwestern Washington and not observed in commercial fields in Idaho, Oregon, and Washington. Stem rust has not been observed or reported so far in the Pacific Northwest.