Report No.7
 July 10, 1996
 
 
 From:
 
 CEREAL RUST LABORATORY
 U.S. DEPARTMENT OF AGRICULTURE
 UNIVERSITY OF MINNESOTA, ST. PAUL  55108
 
 (612) 625-6299    FAX (612) 649-5054
 Internet: markh@puccini.crl.umn.edu
 CRL web page - http://www.umn.edu/rustlab/
 
 
 Issued by:
 
 AGRICULTURAL RESEARCH SERVICE 
 U.S. DEPARTMENT OF AGRICULTURE 
 (In cooperation with the Minnesota 
 Agricultural Experiment Station)
 
 
 
 
 
       ¥      Wheat stem rust has been found in fields in southern 
                    Nebraska, southern Wisconsin, and Michigan.
 
       ¥      Trace amounts of wheat leaf rust have been found as far 
                    north as Winnipeg, Canada. 
 
 
 Winter wheat harvest is in full swing from North Carolina to southern 
 Nebraska.  In many  areas like northern Kansas, yields and test weights 
 are better than expected even after the poor weather conditions of the 
 late winter and spring.  In the Upper Midwest, the hot dry weather in 
 late June and early July has accelerated plant growth of the 
 spring-sown small grains.  However, maturity of the crops is still 
 behind average development for this time of the year because of the 
 late planting and cool spring.
 
 Wheat stem rust.
 
       During late June, wheat stem rust was found at trace-40% 
 severities in plots and trace-1% severities in fields of susceptible 
 cultivars in northern Kansas and southern Nebraska at the soft dough 
 growth stage.  The first stem rust infections in this area occurred 
 when stem rust spore-laden rains fell 14-21 days ago.  The hot dry 
 weather in late June in this area was not conducive for rust increase.
 There have been no new wheat stem rust races identified since CRB #6.
 
       In late June, traces of stem rust were found on winter wheat 
 plants growing in fields in Racine and Dane counties in southern 
 Wisconsin.  The hot dry weather in early July slowed rust development
 and since the crop is close to maturity, losses to rust will be minimal. 
 
       In early July, traces of stem rust have been found widespread in 
 Michigan.
 
       During the second week of July, trace amounts of stem rust were 
 found in plots in Pullman, Washington.
 
 Wheat leaf rust.
 
       During the last week in June, 40% leaf rust severities were 
 observed in a few fields and plots of susceptible cultivars at the soft 
 dough growth stage in northern Kansas and southern Nebraska. In many of 
 these plots fewer cultivars were infected with rust than in previous 
 years.  Since the rust development was late this year, rust losses will 
 be very light in both Kansas and Nebraska.
 
       On June 28, traces of wheat leaf rust were found in west central 
 Minnesota and east central South Dakota nurseries.  This was two weeks 
 later than the normal first date of observation of wheat leaf rust at 
 these two locations.   During early July, traces of leaf rust were 
 found in spring wheat plots in central and east central North Dakota 
 and traces in a winter wheat field in east central North Dakota. 
 
       On June 28, traces of leaf rust were found on upper leaves 
 of susceptible spring wheat cultivars in plots 65 km southwest of 
 Winnipeg, Canada.  This first date of observation was 10-14 days later 
 than in the past two years. 
 
       In early July, leaf rust was severe in susceptible cultivars 
 growing throughout Michigan.  
 
       During the first week in July, leaf rust was light on winter 
 wheats across the state of New York.   Severities ranged from trace 
 to 10% on flag leaves at the hard dough stage.
 
        Rains in eastern Washington and eastern Oregon during the last 
 week in June created ideal conditions for rust increase and leaf rust 
 severities on susceptible wheats have increased significantly.
 
       There have been no new leaf rust race identifications since CRB 
 #6. 
 
 Wheat stripe rust.
 
    In the Pacific Northwest, rust buildup on the soft white wheats has 
 been light since most of the major cultivars are resistant to stripe 
 rust. 
 
 Oat stem rust.
 
       The first detection of oat stem rust in the central plains this 
 year was during the last week in June in oat fields in north central 
 Kansas.  Single pustules were found on oat stems where spores had been 
 deposited 14-21 days ago. 
 
 Oat crown rust.
 
       In early July, crown rust was light to moderate in southern 
 Wisconsin and southern Minnesota oat fields.  During the second week 
 in July, traces of crown rust were found in a oat field in west central 
 Minnesota and in the same field, 20% severities were found on wild oat 
 plants. 
 
 Barley stem rust.
 
       As of July 9, no barley stem rust has been reported in the U.S. 
 this year.
 
 Barley leaf rust.
 
       By late June, traces of barley leaf rust were observed in plots in 
 east central South Dakota and west central Minnesota.  In early July, 
 traces of leaf rust were found in a barley field in west central 
 Minnesota.
 
 Barley stripe rust.
 
       During the first week in July,  stripe rust was starting to 
 increase in spring barley fields and plots in northern Idaho and 
 eastern Washington.  In plots 40 miles west of Pullman, Washington, 
 100% rust severities were observed.  In the Pacific Northwest this 
 year, there was observed a range in adult plant resistance in 
 different cultivars to barley stripe rust.
 
 Rye leaf rust.
 
       In early July, leaf rust was heavy on the lower leaves of rye 
 plants in a west central Wisconsin field.
 
 Stem rust on barberry.
 
       There have been no new reports of stem rust on barberry since the 
 last bulletin.
 
 Crown rust on buckthorn.
 
       During the last week in June, a new set of aecia were found on 
 buckthorn growing in hedges in St, Paul, Minnesota.  This is the 
 latest that actively sporulating aecia have been found on buckthorn 
 in Minnesota in the last 8 years.  Oats growing near these hedges 
 are heavily infected with crown rust.