CEREAL RUST BULLETIN Report No. 2 April 22, 1998 Issued by: Cereal Disease Laboratory U.S. Department of Agriculture Agricultural Research Service University of Minnesota 1551 Lindig St, St. Paul , MN 55108-6052 (612) 625-6299 FAX (612) 649-5054 Internet: markh@puccini.crl.umn.edu For the latest cereal rust news from the field, subscribe to the cereal-rust- survey mail list. To subscribe, send an email message with the word subscribe in the message body (not subject line) to: cereal-rust-survey-request@coafes.umn.edu Reports from this mail list and the Cereal Rust Bulletins are maintained on the CRL web page (http://www.crl.umn.edu/). ______________________________________________________________________________ * Leaf rust is severe in central Texas plots and fields, but light in most other areas of the U.S. * As of April 21, no wheat or barley stem rust has been found in the U.S. ______________________________________________________________________________ The winter-sown small grain crop is generally in good condition. In the southern Great Plains, the majority of the wheat crop is near normal crop maturity. In most of the southeastern soft red winter wheat area, the crop is in good shape. In the northern spring grain growing area, planting has commenced. Wheat stem rust As of April 20, no wheat stem rust has been reported in the U.S. this year. Wheat leaf rust During the second week in April, leaf rust was much more widely distributed than normal within wheat fields in southern Texas and the Gulf Coast states, but average severity of leaf rust was low (Fig. 1). In some of this area, Septoria was severe on the lower leaves, destroying much of the leaf area where rust normally would be increasing. Cool, moist conditions in central Texas where during the past two weeks has created good conditions for rust and powdery mildew increase. In mid-April, leaf rust severities of 80% were observed in central Texas plots of TAM-107 at Temple and in the same plots three weeks ago, only traces were found. In central Texas fields of the variety 2180, severities of 10% were observed on the flag leaves. In mid-April, leaf rust was light throughout Oklahoma. As stated in bulletin #1, the dry weather in Oklahoma in late February and March dried up the leaf rust pustules and put an early end to much of the spore production. During mid-April, leaf rust was light in plots of susceptible southern soft red winter wheat cultivars throughout the southeastern U.S. Moisture and overcast conditions have created ideal conditions for rust development, but the cool nights have slowed the rust increase. In mid-April, traces of leaf rust were found on the lower leaves of wheat in North Carolina plots. In mid-April, light amounts of leaf rust were reported in wheat fields in east central and northeastern Arkansas. During the third week in April, leaf rust was light in wheat plots and fields in the San Joaquin and Sacramento Valleys of California. Wheat stripe rust During the second week in April, wheat stripe rust was present in light to severe amounts in varietal plots in the San Joaquin and Sacramento Valleys of California. In mid-April, traces of wheat stripe were found in only one plot in southern Louisiana. In mid-April, a hot spot of wheat stripe rust was found in an east central Arkansas field. During mid-April, wheat stripe rust was increasing in central and the Walla Walla areas of Washington. Presently, the cool and moist conditions are ideal for the development of wheat stripe rust. Oat stem rust There have been no new reports of oat stem rust since the last bulletin. Usually by this date, severe oat stem rust has been reported in plots in southern Louisiana. Oat crown rust In mid-April, crown rust was light in southeastern U.S. fields, where normally by this date it is severe. During mid-April, crown rust severities were less than 30% in susceptible oat plots in Baton Rouge, Louisiana and Fairhope, Alabama. Crown rust is severe in the Beeville, Texas plots and increasing in the Temple, Texas plots, but it was hard to find in Texas fields. This year the crown rust development is less than normal and these southern areas will provide less inoculum for areas farther north. Barley stem rust As of April 21, no barley stem rust has been reported in the U.S. Limited amounts of barley are grown commercially in the southern states. Stem rust on barley rarely occurs in this area. Barley leaf rust In early April, light amounts of barley leaf rust were reported in plots in the San Joaquin Valley of California. Stripe rust on barley During the second week in April, stripe rust was present in light to severe amounts in barley varietal plots in the San Joaquin and Sacramento Valleys of California. In mid-April, stripe rust was not found on winter barley in northwestern Oregon. Rye rusts There have been no new reports of rye rust since the last bulletin.