Summary of the Cereal Rust Situation in the United States in 2005
USDA-ARS Cereal Disease Laboratory
St. Paul, Minnesota

Wheat leaf rust (caused by Puccinia triticina)

Wheat leaf rust was widespread throughout the Great Plains region in 2005. Leaf rust was first found in late January in the southern Gulf Coast region.  In early April leaf rust was common throughout the Southeast.  By late April and early May leaf rust was common in North Carolina and Virginia.  Leaf rust was found in mid April from Texas to Nebraska. By mid-May leaf rust was common and heavy on susceptible wheat cultivars from Texas to Kansas.  Leaf rust was initially found on winter wheat in the northern plains of Minnesota in mid May.  By mid July leaf rust was widespread and heavy on susceptible spring and winter wheats across much of the northern plains. 

Wheat stripe rust (caused by Puccinia striiformis  f. sp. tritici)

Wheat stripe rust was commonly found in the southern Great Plains in 2005.  Stripe rust infections were found in Texas in mid February.  Cool weather in April and May allowed stripe rust to increase and become widespread throughout the southern and central Great Plains.  Significant yield losses due to stripe rust occurred.  Stripe rust was not commonly found in the northern Great Plains due to high temperatures in June and July in the region.

In early February, heavy stripe rust was observed in plots in southern Louisiana and by early March was severe in southwestern Arkansas.  In late March, stripe rust was severe in fields throughout Louisiana and Arkansas and many fields were sprayed to control stripe rust.  Losses to stripe rust were expected throughout the area. 

By late April, stripe rust was widespread and severe from Florida to southeastern Virginia.

In early June, severe stripe rust was found in fields and plots from Missouri to east central Indiana. 

Wheat stripe rust was widespread and heavy from California to Washington in 2005.  In early March, light stripe rust was detected in plots in the Sacramento Valley of California.  By late April, stripe was severe in fields in the Sacramento Valley.  Severe stripe rust was found in plots in northwestern Washington in early March.  The winter was warmer than normal in the Pacific Northwest, and therefore, stripe rust started sporulating earlier than normal in the western Pacific Northwest.  By early May, stripe rust was present throughout the Pacific Northwest and caused yield losses in susceptible winter wheat fields in northwestern Oregon, northern Idaho and south central Washington.  In early June, stripe rust had passed peak development on winter wheat and was developing on spring wheat.  By late June, stripe rust was severe in virtually every location wheat was grown in the Pacific Northwest, extending as far east as Bozeman, MT.  This year wheat stripe rust losses are expected to be higher than average in the Pacific Northwest. 

Wheat stem rust (caused by Puccinia graminis f. sp. tritici)

The incidence of wheat stem rust in 2005 was low in the U.S.  The disease was first found in late April in Texas.  By early July stem rust was found on susceptible wheats in southern Minnesota.  In late July stem rust was found in northern Minnesota and eastern North Dakota.  Most wheat cultivars grown in the U.S. are resistant to the current stem rust races. 

Oat stem rust (caused by Puccina graminis f. sp. avenae)

Oat stem rust was widespread throughout the Great Plains region in 2005.  Oat stem rust infections were found in south Texas in early March.  Cool wet weather allowed for rust to increase and by early May stem rust on oats had increased to severe levels in southern Texas.  In mid-July oat fields and plots had trace to 10% severities throughout the northern plains.  Most current oat cultivars are not highly resistant to stem rust.  Oat stem rust was also found in Aberdeen, ID where the disease was rarely observed in the past.

Oat crown rust (caused by Puccinia coronata)

Oat crown rust was found widespread throughout the oat growing areas of the U.S. in 2005.  By early March susceptible cultivars in central Texas and southern Louisiana were severely rusted.  By early July, oat crown rust was common on cultivated and wild oat throughout the northern Great Plains and the Upper Midwest.  Many of the primary infections in these regions originated from common buckthorn (Rhamnus cathartica, the alternate host for P. coronata), which is common throughout the Upper Midwest.

Stripe rust on barley (caused by Puccinia striiformis f. sp. hordei)

Barley stripe rust was widespread in the western U.S. barley growing areas in 2005.  Barley stripe rust developed earlier than wheat stripe rust this year in California.  By mid-May, barley stripe rust infections were light in eastern Washington fields and plots.  This was the earliest detection of barley stripe rust in eastern Washington in the last five years.  In late June, stripe rust was increasing rapidly in susceptible fields in eastern Washington and northern Idaho and caused significant yield losses.  Barley stripe rust was also found in southern Idaho.

Barley leaf rust (caused by Puccinia hordei)

Barley leaf rust was widespread throughout the Great Plains and western U.S. regions in 2005.  In late March traces of barley leaf rust were found in southern Texas plots and by mid-May severe leaf rust was found in north central Oklahoma plots.  In early July, rust was widespread and severe in the northern Great Plains.  In mid May rust was severe in central California plots and by mid-June, barley leaf rust was reported in northwestern Washington.

Rye leaf rust (caused by Puccinia recondita f. sp. secalis)

Rye leaf rust was widespread and severe wherever rye was grown in the U.S. in 2005.  In late-March rye leaf rust was common and heavy in central Texas plots.  By mid-May, rye leaf rust was severe and common in north central Oklahoma fields.  In early June, rye leaf rust was common and severe in southwestern Indiana and southern Minnesota plots.  In late July, rye leaf rust was heavy and common throughout the northern Great Plains.

Stem rust on barberry (Berberis vulgare, the alternate host for Puccinia graminis)

In late May, aecial infections were common on susceptible barberry growing in woody areas in southeastern Minnesota, similar to the level of infections in 2003 and 2004.  Most aecial infections were due to the specialized form that infects rye.  In mid-June, aecial infections were light on susceptible common barberry bushes in southern New York.

The Cereal Disease Laboratory (www.cdl.umn.edu) publishes the Cereal Rust Bulletin (http://www.cdl.umn.edu/crb/crbupd.html) bi-weekly from April through early August. 

In addition to the bulletins, the CDL provides updated information on the cereal rust situation in the U.S. as well as information on other areas of cereal rust research through the cereal rust survey mail list (http://www.cdl.umn.edu/mail_lists/mail_lst.html) and our home page (www.cdl.umn.edu).